Misfires - long term fuel trim on bank 1 of over 80%
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
Misfires - long term fuel trim on bank 1 of over 80%
I posted in the CLS63 forum but it looks like this is a better place. I reviewed the sticky's for misfires but wanted to get some opinions as my scenario seems a bit different.
Plugs changed in the last 500 miles (Bosh ZR6SII3320) and 3 plug wires changed as they were damaged in the process. I did mark the socket for indexing and they all went in with the mark on the bottom. All were torqued to spec. Car ran fine for 500 miles after plug change. There is no sign of oil at the ECU plugs but some of the camshaft sensors do have oil in them which I will replace. The only codes I get are misfires and the following scenario is repeatable.
I scoped the cylinders during the plug change and had no signs of scoring.
My 2012 CLS 63 just started having serious misfire issue yesterday. When the engine is cold it ran great with no codes. As soon as it gets to operating temperature it starts throwing misfire codes on cylinder 1 and 4 and runs rough but not terrible. If I continue to drive it, misfires progress to cylinders 5 and 8 and barely runs and bucks. I limped the car back at 20mph. It eventually stalled but did restart. It seems like fuel is dumping into the cylinders at least on bank 1. I swapped coils between 1 and 2 but misfires stayed on 1 and 4
I checked live data and noticed while idling it had a long term fuel trim on bank 1 of over 80% and bank 2 was 15%. Fuel rail pressure was 11510 kPa. I started it cold the next morning and it was around 45% and climbing.
It seems very odd that when it's really bad, the misfires are on the front and back 2 cylinders. Is this likely to be a fuel delivery issue causing the misfires?
The car is undriveable now and in a parking lot 2 hours from home so it will be difficult for me to do much more than change coils and camshaft sensors. Other than that it will need to be towed to a dealer which I really want to avoid.
Plugs changed in the last 500 miles (Bosh ZR6SII3320) and 3 plug wires changed as they were damaged in the process. I did mark the socket for indexing and they all went in with the mark on the bottom. All were torqued to spec. Car ran fine for 500 miles after plug change. There is no sign of oil at the ECU plugs but some of the camshaft sensors do have oil in them which I will replace. The only codes I get are misfires and the following scenario is repeatable.
I scoped the cylinders during the plug change and had no signs of scoring.
My 2012 CLS 63 just started having serious misfire issue yesterday. When the engine is cold it ran great with no codes. As soon as it gets to operating temperature it starts throwing misfire codes on cylinder 1 and 4 and runs rough but not terrible. If I continue to drive it, misfires progress to cylinders 5 and 8 and barely runs and bucks. I limped the car back at 20mph. It eventually stalled but did restart. It seems like fuel is dumping into the cylinders at least on bank 1. I swapped coils between 1 and 2 but misfires stayed on 1 and 4
I checked live data and noticed while idling it had a long term fuel trim on bank 1 of over 80% and bank 2 was 15%. Fuel rail pressure was 11510 kPa. I started it cold the next morning and it was around 45% and climbing.
It seems very odd that when it's really bad, the misfires are on the front and back 2 cylinders. Is this likely to be a fuel delivery issue causing the misfires?
The car is undriveable now and in a parking lot 2 hours from home so it will be difficult for me to do much more than change coils and camshaft sensors. Other than that it will need to be towed to a dealer which I really want to avoid.
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
WALKING RANDOM MISFIRES
I posted in the CLS63 forum but it looks like this is a better place. I reviewed the sticky's for misfires but wanted to get some opinions as my scenario seems a bit different.
Plugs changed in the last 500 miles (Bosh ZR6SII3320) and 3 plug wires changed as they were damaged in the process. I did mark the socket for indexing and they all went in with the mark on the bottom. All were torqued to spec. Car ran fine for 500 miles after plug change. There is no sign of oil at the ECU plugs but some of the camshaft sensors do have oil in them which I will replace. The only codes I get are misfires and the following scenario is repeatable.
I scoped the cylinders during the plug change and had no signs of scoring.
My 2012 CLS 63 just started having serious misfire issue yesterday. When the engine is cold it ran great with no codes. As soon as it gets to operating temperature it starts throwing misfire codes on cylinder 1 and 4 and runs rough but not terrible. If I continue to drive it, misfires progress to cylinders 5 and 8 and barely runs and bucks. I limped the car back at 20mph. It eventually stalled but did restart. It seems like fuel is dumping into the cylinders at least on bank 1. I swapped coils between 1 and 2 but misfires stayed on 1 and 4
I checked live data and noticed while idling it had a long term fuel trim on bank 1 of over 80% and bank 2 was 15%. Fuel rail pressure was 11510 kPa. I started it cold the next morning and it was around 45% and climbing.
It seems very odd that when it's really bad, the misfires are on the front and back 2 cylinders. Is this likely to be a fuel delivery issue causing the misfires?
The car is undriveable now and in a parking lot 2 hours from home so it will be difficult for me to do much more than change coils and camshaft sensors. Other than that it will need to be towed to a dealer which I really want to avoid.
Plugs changed in the last 500 miles (Bosh ZR6SII3320) and 3 plug wires changed as they were damaged in the process. I did mark the socket for indexing and they all went in with the mark on the bottom. All were torqued to spec. Car ran fine for 500 miles after plug change. There is no sign of oil at the ECU plugs but some of the camshaft sensors do have oil in them which I will replace. The only codes I get are misfires and the following scenario is repeatable.
I scoped the cylinders during the plug change and had no signs of scoring.
My 2012 CLS 63 just started having serious misfire issue yesterday. When the engine is cold it ran great with no codes. As soon as it gets to operating temperature it starts throwing misfire codes on cylinder 1 and 4 and runs rough but not terrible. If I continue to drive it, misfires progress to cylinders 5 and 8 and barely runs and bucks. I limped the car back at 20mph. It eventually stalled but did restart. It seems like fuel is dumping into the cylinders at least on bank 1. I swapped coils between 1 and 2 but misfires stayed on 1 and 4
I checked live data and noticed while idling it had a long term fuel trim on bank 1 of over 80% and bank 2 was 15%. Fuel rail pressure was 11510 kPa. I started it cold the next morning and it was around 45% and climbing.
It seems very odd that when it's really bad, the misfires are on the front and back 2 cylinders. Is this likely to be a fuel delivery issue causing the misfires?
The car is undriveable now and in a parking lot 2 hours from home so it will be difficult for me to do much more than change coils and camshaft sensors. Other than that it will need to be towed to a dealer which I really want to avoid.
Let's not replace perfectly good parts for kicks.
One thing I miss is historical...
Q: how was engine running before your replaced the now well indexed plugs ??
Q: What got you into swapping plugs... lean fish-bites or strong throttle ??
Your extreme LTFT-1 suggest Bk1 ignition is A-ok and fuel is not. Let's focus on that... step all over fuel delivery.
In the end it may very well be simply the stock ALT control bug messing up both spark + fuel.
Despite all that... your B2 rail pressure is good at 1,700Psi.... so that hints at ok LPFP. but we need it checked for good measure. The tank supply goes bad for many reasons : filter or pump.
Based on known evidences...
I'd rank "walking random misfires" as follow:
- low (yo-yo) chassis voltage
- LPFP tank 60Psi pressure unstable
- 2x HPFP 1500Psi
- (spark 90% likely ok)
- (NOT leaky Cyl. heads/rings)
Hope this helps funnel further down.
> The walking randomness affirms:
-- ok injectors
-- ok ignition: (coils+boots+plugs)
> Commun factors are..:
1x LPFP feeds 2x HPFP
buggy voltage chaos from 11.x to 14.9
BEWARE of 11.x yo-yo drain mixed with normal voltage swings.
>> 1mn sanity test/fix... Bingo?
-- UNPLUG "BATT SENSOR"!
-- Voltage now 95% perfect (unless oily-ALT)
After the step of "voltage fix"
-- it's either golden....
-- or use scanner to read fuel supply pressures from Tank Pump module + ECU.
It ran good for 500Mi.... we know random is not:
-- leaky cyl. condition
-- ignition
-- injectors
LTFT is super rich.
Last edited by CaliBenzDriver; Jun 2, 2025 at 03:24 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
Thanks for the feedback. I'm not familiar with "ALT Control Bug" phrase. Is the related to an alternator issue?
I did check ECU voltage and it seemed to always be between 13.5 and 14. Since it wasn't below 12v I did not pay much attention.
I purchased the car 4 years ago with 64k miles and it now has 107k. It has run perfectly the entire time I've owned. I had bought Bosch plugs but never got around to putting them and so I finally did that job. I do not know for sure but they could have been the original plugs in it. Nothing about performance led to me changing them, just mileage.
I will change the camshaft sensors since they do have oil in them and should be done regardless.
I have noticed a slightly slower crank occasionally but never to the point where I had to turn the key twice. Just slightly slower.
Could you tell me where the "Batt Sensor" is? Is it part of the connection at the battery? I agree that unstable voltage can cause all kinds of unrelated symptoms. I'll do a lot of digging through the forum for more information.
This W212 forum is great. Thanks for the information.
I did check ECU voltage and it seemed to always be between 13.5 and 14. Since it wasn't below 12v I did not pay much attention.
I purchased the car 4 years ago with 64k miles and it now has 107k. It has run perfectly the entire time I've owned. I had bought Bosch plugs but never got around to putting them and so I finally did that job. I do not know for sure but they could have been the original plugs in it. Nothing about performance led to me changing them, just mileage.
I will change the camshaft sensors since they do have oil in them and should be done regardless.
I have noticed a slightly slower crank occasionally but never to the point where I had to turn the key twice. Just slightly slower.
Could you tell me where the "Batt Sensor" is? Is it part of the connection at the battery? I agree that unstable voltage can cause all kinds of unrelated symptoms. I'll do a lot of digging through the forum for more information.
This W212 forum is great. Thanks for the information.
Last edited by rnettleship; Jun 2, 2025 at 03:25 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
fuel delivery: TANK
Okay, with that said then.... tank filter becomes No1 suspect but not guilty until tested bad so we know before/after.
Read pressure data from tank pump module with scanner both idle and under load.
See it drop from 60psi.
Fancy pump itself can go bad as well with high current. Read module data.
How is idle LTFT : Bk2 compared to Bk1 ??
"Battery sensor" connector is located on the main battery (-) side to Hyundai module.
Based on what you report you may not have the buggy yo-yo 11.x drain, only stock swings.
Ok to ignore while focused on pressure.
Bottom line:
the unstable fuel pressure may be causing your random lean misfires. TBD.
Read pressure data from tank pump module with scanner both idle and under load.
See it drop from 60psi.
Fancy pump itself can go bad as well with high current. Read module data.
How is idle LTFT : Bk2 compared to Bk1 ??
"Battery sensor" connector is located on the main battery (-) side to Hyundai module.
Based on what you report you may not have the buggy yo-yo 11.x drain, only stock swings.
Ok to ignore while focused on pressure.
Bottom line:
the unstable fuel pressure may be causing your random lean misfires. TBD.
Last edited by CaliBenzDriver; Jun 2, 2025 at 07:32 PM.
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
The LTFT on Bank 2 was reading about 15% when bank 1 was 80%. This was when it only had misfires on 1 and 4 though at idle. I don't have a high end scan tool just an iCarsoft so I think I can only capture a few data points at a time.
I will be able to look at this again on Friday. Luckily it's at my companies work location so it's safe. With the advice received on this forum I have a much better idea of what I can check. If it points to low pressure fuel pump issue I'll need to have someone else do it as I can't reasonably do that job in a parking lot. I would tackle high pressure though.
From what I'm seeing, it sounds like the misfires on 5 and 8 might just be sympathetic. I'm struggling to understand the relationship of misfires on 1 and 4 consistently if it's a fuel delivery problem on that side of the engine. I never see misfires on 2 and 3. If I am loosing fuel volume, does it make sense that it mostly impacts the outer cylinders and not the inner?
I will be able to look at this again on Friday. Luckily it's at my companies work location so it's safe. With the advice received on this forum I have a much better idea of what I can check. If it points to low pressure fuel pump issue I'll need to have someone else do it as I can't reasonably do that job in a parking lot. I would tackle high pressure though.
From what I'm seeing, it sounds like the misfires on 5 and 8 might just be sympathetic. I'm struggling to understand the relationship of misfires on 1 and 4 consistently if it's a fuel delivery problem on that side of the engine. I never see misfires on 2 and 3. If I am loosing fuel volume, does it make sense that it mostly impacts the outer cylinders and not the inner?
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
fuel pump supply
The link to Master Tasos provided by Peter stresses that Low fuel supply kills old HPFP by scoring their piston-rod lubricated by fuel itself.
That explains how Bank1 can be starved and not Bank2.
Read your tank pressure data at idle and under load to see it drop.
From there figure what is filter only or tank pump included based on evidence of high-current or faults.
Besides Bosch HPFP are rated for 100kMi, no surprise. Beyond that mileage pressure drops and ram begin to get harder, roller bearings run flat... no point in stretching lifespan to mow-down cam. lobes.
We best need derated pressure as evidence to go forward.
Scanner can read the HPFP metering valve: Compare B1/B2: that's your giveaway diagnosis here.
++++
Q: The basic iCarsoft MB scanner should be more than enough to read live data your ECU + Tank controller. We don't need charts, only hard evidence for repairs.
Q: Why 1+4 misfire and not 2+3 : the cyl. that misfire first have the most lean individual trims and the lowest compressions.
That explains how Bank1 can be starved and not Bank2.
Read your tank pressure data at idle and under load to see it drop.
From there figure what is filter only or tank pump included based on evidence of high-current or faults.
Besides Bosch HPFP are rated for 100kMi, no surprise. Beyond that mileage pressure drops and ram begin to get harder, roller bearings run flat... no point in stretching lifespan to mow-down cam. lobes.
We best need derated pressure as evidence to go forward.
Scanner can read the HPFP metering valve: Compare B1/B2: that's your giveaway diagnosis here.
++++
Q: The basic iCarsoft MB scanner should be more than enough to read live data your ECU + Tank controller. We don't need charts, only hard evidence for repairs.
Q: Why 1+4 misfire and not 2+3 : the cyl. that misfire first have the most lean individual trims and the lowest compressions.
Last edited by CaliBenzDriver; Jun 3, 2025 at 01:42 PM.
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Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
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From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
Thanks for the info. I feel like everything I've been told on this forum will put me in a good position to diagnose. I'll report back what I learn on Friday. I have everything I need at home to fix whatever is wrong but being in parking lot 2 hours from home is a killer.
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Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Thanks for the info. I feel like everything I've been told on this forum will put me in a good position to diagnose. I'll report back what I learn on Friday. I have everything I need at home to fix whatever is wrong but being in parking lot 2 hours from home is a killer.
Last edited by CaliBenzDriver; Jun 3, 2025 at 05:45 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
Round 2.... New plugs and coils on 1 and 4, New battery and 4 new camshaft sensors since mine were original and oil in the connectors.
Results.... Starts fine, after a minute I can feel a light misfire which produces misfire codes on 1 and 4. this is the same symptom I've had all along. Without putting it in gear the symptoms get worse if I give it a little throttle. If I try to drive even a short distance with light throttle It get severe misfires. This time I got hem on 1,2,3 and 4 and 5
Can anyone discern from the data I collected if I can rule out the electric fuel pump? If so, does it make sense to change 1 or both of the High pressure pumps?
I collected some data but in short I'm not sure what to do with it. Fuel pressure at idle was 1,500 psi, Long term fuel trim on back one was extremely high, also high on bank 2. I captured live data from the fuel pump control This data is at idle and running poorly with misfires. I don't see any reading for pressure, just amps for the electric pump.
Date (D/M/Y):06/06/2025
================================================== ======================
BENZ_EN_TEST_00028>CLS(218)>Gasoline>218.974 - CLS 63 AMG>Manual>FSCU - Fuel
Pump Control Unit>View Data>All datastream:
Total Frames: 5 , Supported Items: 9
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/5:
Inside temperature of control module(Driver stage A) ----- 134.60°F
Inside temperature of control module(Driver stage B) ----- 136.40°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.50A
Supply line(Phase A) ----- 2.90A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 2/5:
Inside temperature of control module(Driver stage A) ----- 134.60°F
Inside temperature of control module(Driver stage B) ----- 136.40°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.70A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41.50%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 3/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.60A
Supply line(Phase A) ----- 2.90A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 4/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.80A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 5/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.60A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41.50%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
General live data:
================================================== ======================
OBD_EN_TEST_00005>Freeze Frame:
Supported Items: 32
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/1:
DTC that caused required freeze frame data storage ----- P0300
Fuel system 1 status ----- CL
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 27.1%
Engine Coolant Temperature ----- 206°F
Short Term Fuel Trim B1 ----- 25.0%
Long Term Fuel Trim B1 ----- 63.3%
Short Term Fuel Trim B2 ----- 3.1%
Long Term Fuel Trim B2 ----- 11.7%
Intake Manifold Absolute Pressure ----- 12.0 inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 645 rpm
Vehicle Speed ----- 0 mph
Ignition Timing Advance for #1 Cylinder ----- -2.5°
Intake Air Temperature ----- 107°F
Absolute Throttle Position ----- 13.7%
Time Since Engine Start ----- 13 sec.
Fuel Rail Pressure (gauge) ----- 1782.1 psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 41.6%
Barometric Pressure ----- 29.7 inHg
Control module voltage ----- 13.74V
Absolute Load Value ----- 25.1%
Fuel/Air Commanded Equivalence Ratio ----- 0.999
Relative Throttle Position ----- 2.7%
Ambient air temperature ----- 98°F
Absolute Throttle Position B ----- 13.3%
Accelerator Pedal Position D ----- 5.9%
Accelerator Pedal Position E ----- 6.3%
Commanded Throttle Actuator Control ----- 3.5%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
OBD_EN_TEST_00004>Live Data>All Supported:
Total Frames: 3 , Supported Items: 46
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/3:
Fuel system 1 status ----- OL Fault
Fuel system 2 status ----- OL Fault
Calculated LOAD Value ----- 18.8%
Engine Coolant Temperature ----- 188°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 53.1%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 10.2%
Intake Manifold Absolute Pressure ----- 8.1inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 1251rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 24.5°
Intake Air Temperature ----- 134°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.440V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.455V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 32sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1439.8psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.313inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 0.997
Oxygen Sensor Current (B1-S1) ----- -0.02mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.997
Oxygen Sensor Current (B2-S1) ----- -0.02mA
Catalyst Temperature (B1-S1) ----- 344°F
Catalyst Temperature (B2-S1) ----- 630°F
Control module voltage ----- 13.76V
Absolute Load Value ----- 18.8%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.0%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.5%
Accelerator Pedal Position D ----- 10.6%
Accelerator Pedal Position E ----- 10.2%
Commanded Throttle Actuator Control ----- 2.7%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 2/3:
Fuel system 1 status ----- OL Fault
Fuel system 2 status ----- OL Fault
Calculated LOAD Value ----- 18.8%
Engine Coolant Temperature ----- 188°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 70.3%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 12.5%
Intake Manifold Absolute Pressure ----- 9.6inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 741rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 21.0°
Intake Air Temperature ----- 132°F
Absolute Throttle Position ----- 13.3%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.160V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.655V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 38sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1747.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.313inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.673
Oxygen Sensor Current (B1-S1) ----- 0.88mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.956
Oxygen Sensor Current (B2-S1) ----- -0.15mA
Catalyst Temperature (B1-S1) ----- 345°F
Catalyst Temperature (B2-S1) ----- 654°F
Control module voltage ----- 13.83V
Absolute Load Value ----- 20.4%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.4%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.9%
Accelerator Pedal Position D ----- 11.4%
Accelerator Pedal Position E ----- 11.4%
Commanded Throttle Actuator Control ----- 3.1%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 3/3:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 17.3%
Engine Coolant Temperature ----- 190°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 64.8%
Short Term Fuel Trim B2 ----- 2.3%
Long Term Fuel Trim B2 ----- 11.7%
Intake Manifold Absolute Pressure ----- 9.0inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 842rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 22.5°
Intake Air Temperature ----- 131°F
Absolute Throttle Position ----- 13.3%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.020V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.725V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 45sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1573.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.274inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.697
Oxygen Sensor Current (B1-S1) ----- 0.93mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.988
Oxygen Sensor Current (B2-S1) ----- -0.05mA
Catalyst Temperature (B1-S1) ----- 347°F
Catalyst Temperature (B2-S1) ----- 674°F
Control module voltage ----- 13.74V
Absolute Load Value ----- 18.8%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.0%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.5%
Accelerator Pedal Position D ----- 11.4%
Accelerator Pedal Position E ----- 11.0%
Commanded Throttle Actuator Control ----- 2.7%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
Results.... Starts fine, after a minute I can feel a light misfire which produces misfire codes on 1 and 4. this is the same symptom I've had all along. Without putting it in gear the symptoms get worse if I give it a little throttle. If I try to drive even a short distance with light throttle It get severe misfires. This time I got hem on 1,2,3 and 4 and 5
Can anyone discern from the data I collected if I can rule out the electric fuel pump? If so, does it make sense to change 1 or both of the High pressure pumps?
I collected some data but in short I'm not sure what to do with it. Fuel pressure at idle was 1,500 psi, Long term fuel trim on back one was extremely high, also high on bank 2. I captured live data from the fuel pump control This data is at idle and running poorly with misfires. I don't see any reading for pressure, just amps for the electric pump.
Date (D/M/Y):06/06/2025
================================================== ======================
BENZ_EN_TEST_00028>CLS(218)>Gasoline>218.974 - CLS 63 AMG>Manual>FSCU - Fuel
Pump Control Unit>View Data>All datastream:
Total Frames: 5 , Supported Items: 9
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/5:
Inside temperature of control module(Driver stage A) ----- 134.60°F
Inside temperature of control module(Driver stage B) ----- 136.40°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.50A
Supply line(Phase A) ----- 2.90A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 2/5:
Inside temperature of control module(Driver stage A) ----- 134.60°F
Inside temperature of control module(Driver stage B) ----- 136.40°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.70A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41.50%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 3/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.60A
Supply line(Phase A) ----- 2.90A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 4/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.80A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 5/5:
Inside temperature of control module(Driver stage A) ----- 136.40°F
Inside temperature of control module(Driver stage B) ----- 138.20°F
Inside temperature of control module(Driver stage C) ----- 140°F
Power consumption of component M3(Fuel pump) ----- 3.60A
Supply line(Phase A) ----- 3A
Supply line(Phase B) ----- 3A
Supply line(Phase C) ----- 2.90A
PWM signal of component N118(Fuel pump control module)-Output signal ----- 41.50%
Request of component M3(Fuel pump)by control module N3/10(ME-SFI [ME] control module)
----- ON
General live data:
================================================== ======================
OBD_EN_TEST_00005>Freeze Frame:
Supported Items: 32
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/1:
DTC that caused required freeze frame data storage ----- P0300
Fuel system 1 status ----- CL
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 27.1%
Engine Coolant Temperature ----- 206°F
Short Term Fuel Trim B1 ----- 25.0%
Long Term Fuel Trim B1 ----- 63.3%
Short Term Fuel Trim B2 ----- 3.1%
Long Term Fuel Trim B2 ----- 11.7%
Intake Manifold Absolute Pressure ----- 12.0 inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 645 rpm
Vehicle Speed ----- 0 mph
Ignition Timing Advance for #1 Cylinder ----- -2.5°
Intake Air Temperature ----- 107°F
Absolute Throttle Position ----- 13.7%
Time Since Engine Start ----- 13 sec.
Fuel Rail Pressure (gauge) ----- 1782.1 psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 41.6%
Barometric Pressure ----- 29.7 inHg
Control module voltage ----- 13.74V
Absolute Load Value ----- 25.1%
Fuel/Air Commanded Equivalence Ratio ----- 0.999
Relative Throttle Position ----- 2.7%
Ambient air temperature ----- 98°F
Absolute Throttle Position B ----- 13.3%
Accelerator Pedal Position D ----- 5.9%
Accelerator Pedal Position E ----- 6.3%
Commanded Throttle Actuator Control ----- 3.5%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
OBD_EN_TEST_00004>Live Data>All Supported:
Total Frames: 3 , Supported Items: 46
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/3:
Fuel system 1 status ----- OL Fault
Fuel system 2 status ----- OL Fault
Calculated LOAD Value ----- 18.8%
Engine Coolant Temperature ----- 188°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 53.1%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 10.2%
Intake Manifold Absolute Pressure ----- 8.1inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 1251rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 24.5°
Intake Air Temperature ----- 134°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.440V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.455V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 32sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1439.8psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.313inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 0.997
Oxygen Sensor Current (B1-S1) ----- -0.02mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.997
Oxygen Sensor Current (B2-S1) ----- -0.02mA
Catalyst Temperature (B1-S1) ----- 344°F
Catalyst Temperature (B2-S1) ----- 630°F
Control module voltage ----- 13.76V
Absolute Load Value ----- 18.8%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.0%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.5%
Accelerator Pedal Position D ----- 10.6%
Accelerator Pedal Position E ----- 10.2%
Commanded Throttle Actuator Control ----- 2.7%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 2/3:
Fuel system 1 status ----- OL Fault
Fuel system 2 status ----- OL Fault
Calculated LOAD Value ----- 18.8%
Engine Coolant Temperature ----- 188°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 70.3%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 12.5%
Intake Manifold Absolute Pressure ----- 9.6inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 741rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 21.0°
Intake Air Temperature ----- 132°F
Absolute Throttle Position ----- 13.3%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.160V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.655V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 38sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1747.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.313inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.673
Oxygen Sensor Current (B1-S1) ----- 0.88mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.956
Oxygen Sensor Current (B2-S1) ----- -0.15mA
Catalyst Temperature (B1-S1) ----- 345°F
Catalyst Temperature (B2-S1) ----- 654°F
Control module voltage ----- 13.83V
Absolute Load Value ----- 20.4%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.4%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.9%
Accelerator Pedal Position D ----- 11.4%
Accelerator Pedal Position E ----- 11.4%
Commanded Throttle Actuator Control ----- 3.1%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 3/3:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 17.3%
Engine Coolant Temperature ----- 190°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 64.8%
Short Term Fuel Trim B2 ----- 2.3%
Long Term Fuel Trim B2 ----- 11.7%
Intake Manifold Absolute Pressure ----- 9.0inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 842rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 22.5°
Intake Air Temperature ----- 131°F
Absolute Throttle Position ----- 13.3%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.020V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.725V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 45sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1573.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 44.3%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.274inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.697
Oxygen Sensor Current (B1-S1) ----- 0.93mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.988
Oxygen Sensor Current (B2-S1) ----- -0.05mA
Catalyst Temperature (B1-S1) ----- 347°F
Catalyst Temperature (B2-S1) ----- 674°F
Control module voltage ----- 13.74V
Absolute Load Value ----- 18.8%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 2.0%
Ambient air temperature ----- 96°F
Absolute Throttle Position B ----- 12.5%
Accelerator Pedal Position D ----- 11.4%
Accelerator Pedal Position E ----- 11.0%
Commanded Throttle Actuator Control ----- 2.7%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
Joined: Nov 2016
Posts: 7,847
Likes: 3,496
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Does the LTFT mean you are running lean and fuel is added (e.g., 64%) or does it mean you are running rich by that amount? Regardless, you have a fuel delivery problem on Bank 1. Could a fuel line between the HPFP and injectors be the problem, or even the injectors themselves? Two hours from Jersey? Where is your car? Maybe someone can recommend a good shop near your car.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
I’m going to rent a car hauler trailer and bring it home so I can really dig in. I’ll take the high pressure pump off to see if the one feeding bank 1 is stuck. I’m disappointed I could not read fuel pump pressure with my icarsoft mb II. To determine if I have an issue with the electric pump. At least I could amperage was stabile
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Bk1 lean misfires
that's a lit of interesting data, such as:
B1 is OpenLoop (B2 CL)
B1 CAT is galf as hot as B2
B1 lambda heater is activated all the way.
Fuel rail pressure is only B2.
We see tank pump current show all 3-phases are balanced ie. pump ok.
I dont see
tank pressure
Bank1 rail pressure
HPFP 1+2 Proportioning angles.
What that all mean is HPFP1 best suspect.
B1 is OpenLoop (B2 CL)
B1 CAT is galf as hot as B2
B1 lambda heater is activated all the way.
Fuel rail pressure is only B2.
We see tank pump current show all 3-phases are balanced ie. pump ok.
I dont see
tank pressure
Bank1 rail pressure
HPFP 1+2 Proportioning angles.
What that all mean is HPFP1 best suspect.
Last edited by CaliBenzDriver; Jun 6, 2025 at 08:27 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
I got the car home today and pulled the bank 1 HPFP. I ended up breaking the electrical connector (more brittle than I expected) so I have a new on order.
Pushing the pump down feels slightly "gritty" but it was not stuck which I was hoping to see. The cam lobes look fine and the roller is also undamaged.
If this does not fix the issue I'll put a gauge on the fuel line going to the pumps.
interesting that when the problem started it was just a light misfire cold. The next dat it started light and progressed to significant misfires only after being fully warmed up. Today it started fine but went directly to heavy misfire and would not take any throttle. I had a tough time just getting it on the trailer.
Pushing the pump down feels slightly "gritty" but it was not stuck which I was hoping to see. The cam lobes look fine and the roller is also undamaged.
If this does not fix the issue I'll put a gauge on the fuel line going to the pumps.
interesting that when the problem started it was just a light misfire cold. The next dat it started light and progressed to significant misfires only after being fully warmed up. Today it started fine but went directly to heavy misfire and would not take any throttle. I had a tough time just getting it on the trailer.
MBWorld Fanatic!
Joined: Feb 2017
Posts: 2,304
Likes: 1,206
From: Baltimore County, MD
'13 s212 63 p30. '06 LX470
When you have a cold bank its due to lack of combustion. Id be looking at spark and fuel on that side. You can use a temp gun to diagnose the individual cold cylinder/s to narrow it down.
Last edited by Baltistyle; Jun 8, 2025 at 11:08 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
iCarsoft
The saga continues. I had to replace the bank 1 HPFP because I broke the electrical connection taking it off for inspection. New one installed with the same symptoms. I am struggling with getting good data from my ICarsoft MBII system. I updated to the most recent software but when I go into diagnostic and select my car (W218) 218.374 it does not even show me the ECU and I cannot get live data off the Fuel pump control unit. I can only get fuel pump live data if I select 218.974 and that does not show me fuel pump pressure. All the live data I am capturing is via OBDII.
2012 CLS63
VIN: WDDLJ7EB1CA022929
FIN: WDD2183741A022929
My next plan is to put a gauge on the fuel line feed to the HPFP's
I cleared the codes first and got the following after a few minutes of idling.
THE ECU codes are:
BENZ_EN_TEST_00004>CLS(218)>Gasoline>218.974 - CLS 63 AMG>Manual>ECM - Engine Control Module(MED177 for Combustion Engine M278 (N3-10))>Read Fault Code:
Total Number : 4
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
P050500 1/4
State: Historic
The idle speed control has a malfunction
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
P030185 2/4
State: Current
Combustion misfiring of cylinder 1 has been detected, There is a signal above the permissible limit value
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
P030485 3/4
State: Current
Combustion misfiring of cylinder 4 has been detected, There is a signal above the permissible limit value
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
P030085 4/4
State: Current
Combustion misfiring has been detected, There is a signal above the permissible limit value
The issue has stayed consistent with cylinders 1 and 4. I have replaced those plugs twice and both have new coils.
Here is some live data via OBDII. This is at idle. The car cannot be driven.
OBD_EN_TEST_00001>Live Data>All Supported:
Total Frame: 1 , Supported Items: 46
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Frame 1/1:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 23.5% (This seems high for idling in the garage,
Engine Coolant Temperature ----- 125°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 66.4%
Short Term Fuel Trim B2 ----- 8.6%
Long Term Fuel Trim B2 ----- 12.5%
Intake Manifold Absolute Pressure ----- 9.6inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 646rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 15.0°
Intake Air Temperature ----- 69°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.010V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.225V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 178sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1425.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 41.2%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.391inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.965
Oxygen Sensor Current (B1-S1) ----- 1.16mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.968
Oxygen Sensor Current (B2-S1) ----- -0.14mA
Catalyst Temperature (B1-S1) ----- 739°F
Catalyst Temperature (B2-S1) ----- 758°F
Control module voltage ----- 14.25V
Absolute Load Value ----- 21.6%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 1.6%
Ambient air temperature ----- 68°F
Absolute Throttle Position B ----- 12.2%
Accelerator Pedal Position D ----- 5.9%
Accelerator Pedal Position E ----- 6.3%
Commanded Throttle Actuator Control ----- 2.4%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
2012 CLS63
VIN: WDDLJ7EB1CA022929
FIN: WDD2183741A022929
My next plan is to put a gauge on the fuel line feed to the HPFP's
I cleared the codes first and got the following after a few minutes of idling.
THE ECU codes are:
BENZ_EN_TEST_00004>CLS(218)>Gasoline>218.974 - CLS 63 AMG>Manual>ECM - Engine Control Module(MED177 for Combustion Engine M278 (N3-10))>Read Fault Code:
Total Number : 4
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P050500 1/4
State: Historic
The idle speed control has a malfunction
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P030185 2/4
State: Current
Combustion misfiring of cylinder 1 has been detected, There is a signal above the permissible limit value
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P030485 3/4
State: Current
Combustion misfiring of cylinder 4 has been detected, There is a signal above the permissible limit value
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P030085 4/4
State: Current
Combustion misfiring has been detected, There is a signal above the permissible limit value
The issue has stayed consistent with cylinders 1 and 4. I have replaced those plugs twice and both have new coils.
Here is some live data via OBDII. This is at idle. The car cannot be driven.
OBD_EN_TEST_00001>Live Data>All Supported:
Total Frame: 1 , Supported Items: 46
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Frame 1/1:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 23.5% (This seems high for idling in the garage,
Engine Coolant Temperature ----- 125°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 66.4%
Short Term Fuel Trim B2 ----- 8.6%
Long Term Fuel Trim B2 ----- 12.5%
Intake Manifold Absolute Pressure ----- 9.6inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 646rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 15.0°
Intake Air Temperature ----- 69°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.010V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.225V
Short Term Fuel Trim (B2-S2) ----- 99.2%
Certified OBD Requirements ----- OBD2
Time Since Engine Start ----- 178sec.
Distance Traveled While MIL is Activated ----- 0miles
Fuel Rail Pressure (gauge) ----- 1425.3psi
Commanded Evaporative Purge ----- 0.0%
Fuel Level Input ----- 41.2%
Number of warm-ups since DTCs cleared ----- 0
Distance traveled since DTCs cleared ----- 0miles
Evaporative System Vapor Pressure ----- 0.391inH2O
Barometric Pressure ----- 29.7inHg
Equivalence Ratio (lambda)(B1-S1) ----- 1.965
Oxygen Sensor Current (B1-S1) ----- 1.16mA
Equivalence Ratio (lambda)(B2-S1) ----- 0.968
Oxygen Sensor Current (B2-S1) ----- -0.14mA
Catalyst Temperature (B1-S1) ----- 739°F
Catalyst Temperature (B2-S1) ----- 758°F
Control module voltage ----- 14.25V
Absolute Load Value ----- 21.6%
Fuel/Air Commanded Equivalence Ratio ----- 1.999
Relative Throttle Position ----- 1.6%
Ambient air temperature ----- 68°F
Absolute Throttle Position B ----- 12.2%
Accelerator Pedal Position D ----- 5.9%
Accelerator Pedal Position E ----- 6.3%
Commanded Throttle Actuator Control ----- 2.4%
Type of fuel currently ----- GAS
Long Term Secondary O2 Sensor Fuel Trim-B1 ----- 0.0%
Long Term Secondary O2 Sensor Fuel Trim-B2 ----- 0.0%
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
FUNNELLING DOWN RESULTS
Fuel system 1 status ----- OL Drive <<< OPEN LOOP
Fuel system 2 status ----- CL (Closed loop)
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 66.4% <<<<
Short Term Fuel Trim B2 ----- 8.6%
Long Term Fuel Trim B2 ----- 12.5%
Bank1 is still screaming for more gas despite a good supply, new HPFP and ok B2.
Bank1 is in OPEN-LOOP without a Lambda fault:
How can that be??
Compromised/contaminated Lambda would quickly trigger a code.
There are not faults on bad injectors either. I suggest moving injectors 1+4 around. You may not want to disturb Bank2 or concider if B1 are compromised B2 nor far from it. Don't replace injectors, number them so you can track results: What bank gets lean, what Cyl misfires.
If your iCarsoft sucks... try a $150 "LAUNCH creader" for less aggravations.
I DO SEE PROGRESS!!!
Catalyst Temperature (B1-S1) ----- 739°F
Catalyst Temperature (B2-S1) ----- 758°F
This means your lambda are working and communicating AND bank1 is now hot where it use to stay cold with previous HPFP.
You may just need a little bit of run time...
Is your bank1 rail free of air, right?
Fuel system 2 status ----- CL (Closed loop)
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 66.4% <<<<
Short Term Fuel Trim B2 ----- 8.6%
Long Term Fuel Trim B2 ----- 12.5%
Bank1 is still screaming for more gas despite a good supply, new HPFP and ok B2.
Bank1 is in OPEN-LOOP without a Lambda fault:
How can that be??
Compromised/contaminated Lambda would quickly trigger a code.
There are not faults on bad injectors either. I suggest moving injectors 1+4 around. You may not want to disturb Bank2 or concider if B1 are compromised B2 nor far from it. Don't replace injectors, number them so you can track results: What bank gets lean, what Cyl misfires.
If your iCarsoft sucks... try a $150 "LAUNCH creader" for less aggravations.
I DO SEE PROGRESS!!!
Catalyst Temperature (B1-S1) ----- 739°F
Catalyst Temperature (B2-S1) ----- 758°F
This means your lambda are working and communicating AND bank1 is now hot where it use to stay cold with previous HPFP.
You may just need a little bit of run time...
Is your bank1 rail free of air, right?
Last edited by CaliBenzDriver; Jun 10, 2025 at 02:38 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
Manual gauge on the low pressure side for fuel was 60# at Idle. There was a lot of bouncing +/- 53's but I think that is to be expected.
While running, I pulled the wire connection off cylinder 1 and it made no difference. I pulled the plug and it was wet and black. This has only been in the engine for maybe 10 minutes of run time.
I am going to check continuity through the spark plug wires next to make sure this is not something simple.
Is it reasonable to believe that if this was an O2 sensor issue that it would have impacted all cylinders on that bank? Bank 1 O2 voltage is extremely low.
The engine did seem to run fine for the first minute.
When the Fuel system status tried to flip form OL to CL, it flashed CL for a moment and then both went to OL Fault. By the time I started recording the data, Bank 2 was CL and Bank 1 was OL Drive
Frame 1/2:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 20.0%
Engine Coolant Temperature ----- 190°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 73.4%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 14.1%
Intake Manifold Absolute Pressure ----- 9.3inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 652rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 18.5°
Intake Air Temperature ----- 95°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.015V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.735V
While running, I pulled the wire connection off cylinder 1 and it made no difference. I pulled the plug and it was wet and black. This has only been in the engine for maybe 10 minutes of run time.
I am going to check continuity through the spark plug wires next to make sure this is not something simple.
Is it reasonable to believe that if this was an O2 sensor issue that it would have impacted all cylinders on that bank? Bank 1 O2 voltage is extremely low.
The engine did seem to run fine for the first minute.
When the Fuel system status tried to flip form OL to CL, it flashed CL for a moment and then both went to OL Fault. By the time I started recording the data, Bank 2 was CL and Bank 1 was OL Drive
Frame 1/2:
Fuel system 1 status ----- OL Drive
Fuel system 2 status ----- CL
Calculated LOAD Value ----- 20.0%
Engine Coolant Temperature ----- 190°F
Short Term Fuel Trim B1 ----- 0.0%
Long Term Fuel Trim B1 ----- 73.4%
Short Term Fuel Trim B2 ----- 0.0%
Long Term Fuel Trim B2 ----- 14.1%
Intake Manifold Absolute Pressure ----- 9.3inHg
Engine Speed (Revolutions Per Minute of crankshaft) ----- 652rpm
Vehicle Speed ----- 0mph
Ignition Timing Advance for #1 Cylinder ----- 18.5°
Intake Air Temperature ----- 95°F
Absolute Throttle Position ----- 12.5%
Oxygen Sensor Output Voltage (B1-S2) ----- 0.015V
Short Term Fuel Trim (B1-S2) ----- 99.2%
Oxygen Sensor Output Voltage (B2-S2) ----- 0.735V
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
DISCREPANCIES SCANNER/ECU
We may be dealing with questionable data from the ECU or scanner.
Is Bk1 really staying in "open loop" fuel mode??
Are LTFT-1 truly all the way up??
> RECAP...
-- You can nearly bank on known good Bk1 fuel rail pressure (unless pop valve control is bad: unlikely)
-- What's confirmed are "misfire faults" with wet plug despite new coil + plug.
-- Scanner is not able to read ECU live data.
There is such a thing as cylinder deactivation as far as injectors but I don't know that ECU would cut off ignition on few cyl.
I am not familiar with the limits of iCarsoft scanner. It may be more/less compatible with your chassis or CGW module may prevent DLC CAN-D access to ECU CAN-C.
I'll distrust scanner before ECU.
Is Bk1 really staying in "open loop" fuel mode??
Are LTFT-1 truly all the way up??
> RECAP...
-- You can nearly bank on known good Bk1 fuel rail pressure (unless pop valve control is bad: unlikely)
-- What's confirmed are "misfire faults" with wet plug despite new coil + plug.
-- Scanner is not able to read ECU live data.
There is such a thing as cylinder deactivation as far as injectors but I don't know that ECU would cut off ignition on few cyl.
I am not familiar with the limits of iCarsoft scanner. It may be more/less compatible with your chassis or CGW module may prevent DLC CAN-D access to ECU CAN-C.
I'll distrust scanner before ECU.
Last edited by CaliBenzDriver; Jun 10, 2025 at 06:51 PM.
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
It has a common rail so I only get one rail pressure. After I verify good connectivity from plug to coil I will swap injectors 1/2 and 3/4. Maybe I have two bad injectors dumping fuel
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
that's not impossible but unlikely... mark them up.
COILS:
Don't run coils without plugs it breaches them internally to discharge 30,000. Volts spikes.
UP THE CHAIN:
"Wet plugs" mean no spark...
"new coil + new plug" mean no ECU signal?
How about the coil BOOTS??
Last edited by CaliBenzDriver; Jun 10, 2025 at 07:12 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,951
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 44
Likes: 4
From: New Jersey
2012 CLS63, 2015 GL450, 2014 ML350
I pulled the # 1 coil and plug and thought I found a smoking gun. The coiled wire inside the boot seemed a bit short and I was having difficulty getting continuity from the plug to the end of the wire that connects to the coil. I stretched the wire so it must compress a lot when the coil is mounted. I did the same on Cylinder #4. The car starts fine with no signs of misfire as it has for the last several attempts. I watched the fuel status which remained in Open loop until I reached about 180 degrees. Fuel system 1 and 2 then went to OL Fault or "Open loop due to system failure" and misfires began. Eventually fuel system 2 went to closed loop. I tried my ODBII phone app and found more detail. Fuel system 1 one says "ECU #1: Open loop due to engine load or fuel cut due to deceleration". Same misfires on 1 and 4.
So, I believe all coils are firing until the car warms up. Engine temps were between 180 and 192. I was also starting to suspect plugs but I put in the same ones that came out after 107k miles. Bosch ZR6SII3320
I checked the ECU again and find no evidence of any oil in the harness or on the connectors.
Unless there are any other suggestions, I'll move towards swapping injectors around.
So, I believe all coils are firing until the car warms up. Engine temps were between 180 and 192. I was also starting to suspect plugs but I put in the same ones that came out after 107k miles. Bosch ZR6SII3320
I checked the ECU again and find no evidence of any oil in the harness or on the connectors.
Unless there are any other suggestions, I'll move towards swapping injectors around.
