Elusive mechanical (maybe?) gremlin on my M156 E63
Joined: Nov 2016
Posts: 7,847
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I’m thinking because the coolant was boiling from the engine overheating? The battery was dying completely with it not getting charged from the alternator. It was already a warm day here and I was halfway through my drive.
All the electronics started shutting off but I could not stop the engine. Once I stopped the car, the engine started revving on its own (bad voltage to the ECU maybe?). That, in combination with the radiator fan probably stopped. Radiator go boom!
But in all reality, it must’ve just busted open at a weak point rather than the entire radiator literally exploding into pieces…
All the electronics started shutting off but I could not stop the engine. Once I stopped the car, the engine started revving on its own (bad voltage to the ECU maybe?). That, in combination with the radiator fan probably stopped. Radiator go boom!
But in all reality, it must’ve just busted open at a weak point rather than the entire radiator literally exploding into pieces…
Second, and more of a concern, is when a car fails to turn off. I had that happen to a 2008 Infiniti G35. It turned out that I had water intrusion into the cabin without knowing it. That instrusion (actual pools of water under the carpet) caused failure of some control modules over time. My insurance company totaled the car as flood damaged. If your carpets are damp at all, you may have a problem caused by water intrusion and corrosion. You need to pull up the carpet enough to check for water in the floor pan or damp foam padding. Water damage will cause gremlin-type problems.
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)
I had a similar problem with my C350 with clogged drain channels for the sun roof. Fortunately, I caught the problem in time. Here are the details: https://mbworld.org/forums/c-class-w...78-solved.html
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From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
When your DME gets low voltage it starts doing weird things like messing with your sensors/coils.
Hopefully this isn't permanent, you can brick your DME this way but theyre fairly resilient. I'm way past the point of attempting to diagnose this thing, I'm just here for the ride. I'm by no means the #1 MB guy but it IS my main source of income.
Hopefully this isn't permanent, you can brick your DME this way but theyre fairly resilient. I'm way past the point of attempting to diagnose this thing, I'm just here for the ride. I'm by no means the #1 MB guy but it IS my main source of income.
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Joined: Apr 2025
Posts: 137
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From: Seattle
2010 W212 E63 (M156)
Alright... Another status update; wooo!
So the current shop got the radiator replaced, all new coolant put in, alternator replaced, and all the codes cleared.
Good news:
- They haven't seen any further damage from the radiator going boom, including electrical
- Block test passed, indicating head gasket is fine
- It is back on the road and driving
Bad news:
- Hesitation is still there (to what extent, I'm not sure)
- NEW alternator is failing according to test: "Faulty alternator or voltage regulator: Replace alternator and re-test"
- Voltage is also reporting HIGH now from 14.5-15.2V. Apparently normal range is 13.8-14.4V.
Now thankfully the shop is replacing the alternator AGAIN under their warranty so I'm not being charged twice. Nice policy. After that, I'm going to have them go for a drive and live log cylinder faults and camshaft position angle after resetting all the adaptation again (I think mainly just the fuel trims?, but someone feel free to chime in if there's anything else that needs to be readapted). I'm thinking that the adaptations might take a longer drive, 20-50 miles, for the hesitations to smooth out if the issue has been addressed. Which they're of course not doing for a test drive. So even if the hesitations remain after replacing the alternator again and it testing okay, I'm hoping to not see the faults spiking for cylinder 7 and wild fluctuations of the camshaft position angle during the hesitations events as we saw before. To me, that should indicate the issue is resolved and adaptations just need time.
So the current shop got the radiator replaced, all new coolant put in, alternator replaced, and all the codes cleared.
Good news:
- They haven't seen any further damage from the radiator going boom, including electrical
- Block test passed, indicating head gasket is fine
- It is back on the road and driving
Bad news:
- Hesitation is still there (to what extent, I'm not sure)
- NEW alternator is failing according to test: "Faulty alternator or voltage regulator: Replace alternator and re-test"
- Voltage is also reporting HIGH now from 14.5-15.2V. Apparently normal range is 13.8-14.4V.
Now thankfully the shop is replacing the alternator AGAIN under their warranty so I'm not being charged twice. Nice policy. After that, I'm going to have them go for a drive and live log cylinder faults and camshaft position angle after resetting all the adaptation again (I think mainly just the fuel trims?, but someone feel free to chime in if there's anything else that needs to be readapted). I'm thinking that the adaptations might take a longer drive, 20-50 miles, for the hesitations to smooth out if the issue has been addressed. Which they're of course not doing for a test drive. So even if the hesitations remain after replacing the alternator again and it testing okay, I'm hoping to not see the faults spiking for cylinder 7 and wild fluctuations of the camshaft position angle during the hesitations events as we saw before. To me, that should indicate the issue is resolved and adaptations just need time.
Last edited by ZackaSnack; Jun 2, 2025 at 09:23 PM.
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
FIXING VOLTAGE CHAOS
Alright... Another status update; wooo!
So the current shop got the radiator replaced, all new coolant put in, alternator replaced, and all the codes cleared.
Good news:
- They haven't seen any further damage from the radiator going boom, including electrical
- Block test passed, indicating head gasket is fine
- It is back on the road and driving
Bad news:
- Hesitation is still there (to what extent, I'm not sure)
- NEW alternator is failing according to test: "Faulty alternator or voltage regulator: Replace alternator and re-test"
- Voltage is also reporting HIGH now from 14.5-15.2V. Apparently normal range is 13.8-14.4V.
Now thankfully the shop is replacing the alternator AGAIN under their warranty so I'm not being charged twice. Nice policy. After that, I'm going to have them go for a drive and live log cylinder faults and camshaft position angle after resetting all the adaptation again (I think mainly just the fuel trims?, but someone feel free to chime in if there's anything else that needs to be readapted). I'm thinking that the adaptations might take a longer drive, 20-50 miles, for the hesitations to smooth out if the issue has been addressed. Which they're of course not doing for a test drive. So even if the hesitations remain after replacing the alternator again and it testing okay, I'm hoping to not see the faults spiking for cylinder 7 and wild fluctuations of the camshaft position angle during the hesitations events as we saw before. To me, that should indicate the issue is resolved and adaptations just need time.
So the current shop got the radiator replaced, all new coolant put in, alternator replaced, and all the codes cleared.
Good news:
- They haven't seen any further damage from the radiator going boom, including electrical
- Block test passed, indicating head gasket is fine
- It is back on the road and driving
Bad news:
- Hesitation is still there (to what extent, I'm not sure)
- NEW alternator is failing according to test: "Faulty alternator or voltage regulator: Replace alternator and re-test"
- Voltage is also reporting HIGH now from 14.5-15.2V. Apparently normal range is 13.8-14.4V.
Now thankfully the shop is replacing the alternator AGAIN under their warranty so I'm not being charged twice. Nice policy. After that, I'm going to have them go for a drive and live log cylinder faults and camshaft position angle after resetting all the adaptation again (I think mainly just the fuel trims?, but someone feel free to chime in if there's anything else that needs to be readapted). I'm thinking that the adaptations might take a longer drive, 20-50 miles, for the hesitations to smooth out if the issue has been addressed. Which they're of course not doing for a test drive. So even if the hesitations remain after replacing the alternator again and it testing okay, I'm hoping to not see the faults spiking for cylinder 7 and wild fluctuations of the camshaft position angle during the hesitations events as we saw before. To me, that should indicate the issue is resolved and adaptations just need time.
Back to square one: .... "fixing dead ALT".
Original ALT gets replaced with new unit:
now high voltage: 15.2Volts.
Nothing simple...
at least we found something consistent:
CHASSIS VOLTAGE IS RAINING TROUBLES.
Let's check the oxidized single GND strap is not dishing out glitches under load:
measure voltage between engine block and BATT(-):
-- What is it?
-- Turn up max load, measure the voltage drops how much?
High voltage fries (audio amplifer) modules... You don't want voltage past 14.9V Max.
Last edited by CaliBenzDriver; Jun 2, 2025 at 10:10 PM.
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Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
A lot of good progress happened. Now you have a better than new radiator.
Back to square one: .... "fixing dead ALT".
Original ALT gets replaced with new unit:
now high voltage: 15.2Volts.
Nothing simple...
at least we found something consistent:
CHASSIS VOLTAGE IS RAINING TROUBLES.
Let's check the oxidized single GND strap is not dishing out glitches under load:
measure voltage between engine block and BATT(-):
-- What is it?
-- Turn up max load, measure the voltage drops how much?
High voltage fries (audio amplifer) modules... You don't want voltage past 14.9V Max.
Back to square one: .... "fixing dead ALT".
Original ALT gets replaced with new unit:
now high voltage: 15.2Volts.
Nothing simple...
at least we found something consistent:
CHASSIS VOLTAGE IS RAINING TROUBLES.
Let's check the oxidized single GND strap is not dishing out glitches under load:
measure voltage between engine block and BATT(-):
-- What is it?
-- Turn up max load, measure the voltage drops how much?
High voltage fries (audio amplifer) modules... You don't want voltage past 14.9V Max.
Out Of Control!!
Joined: Jun 2004
Posts: 13,799
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
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Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
ALT VOLTAGE CHAOS
What are the likelyness of getting a bad original alternator replaced by a new also defective alternator, it's slim, right?
Let's see where all this goes...
-- Call a stop at new ECU replacement (> painted GND Ref!)
Be aware that ALL chassis modules got powered by 15.x Voltage....
There's an experimental 1mn test: "ALT-LIN": 14.1V ?
+++ ROOT CAUSE...
May lead to oxidized/painted footwell Ref. GND.
Let's see where all this goes...
-- Call a stop at new ECU replacement (> painted GND Ref!)
Be aware that ALL chassis modules got powered by 15.x Voltage....
There's an experimental 1mn test: "ALT-LIN": 14.1V ?
+++ ROOT CAUSE...
May lead to oxidized/painted footwell Ref. GND.
Last edited by CaliBenzDriver; Jun 3, 2025 at 04:36 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
What are the likelyness of getting a bad original alternator replaced by a new also defective alternator, it's slim, right?
Let's see where all this goes...
-- Call a stop at new ECU replacement (> painted GND Ref!)
Be aware that ALL chassis modules got powered by 15.x Voltage....
There's an experimental 1mn test: "ALT-LIN": 14.1V ?
+++ ROOT CAUSE...
May lead to oxidized/painted footwell Ref. GND.
Let's see where all this goes...
-- Call a stop at new ECU replacement (> painted GND Ref!)
Be aware that ALL chassis modules got powered by 15.x Voltage....
There's an experimental 1mn test: "ALT-LIN": 14.1V ?
+++ ROOT CAUSE...
May lead to oxidized/painted footwell Ref. GND.
Also the shop's owner has a W204 C63 where the exact same thing happened. Overvoltage, xentry alternator test failed with no other codes. 2nd new alternator worked fine. Maybe Bosch manufacturing defect.
Wiring harness or ECU issues are definitely on my mind though. Considering everything I've done at this point, I have low expectations.
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
AWAY FROM CHAOS
Apparently it happens. Saw this post I referenced before where someone's first replacement seemed to be bad: https://mbworld.org/forums/w212-amg/...ml#post7075020
Also the shop's owner has a W204 C63 where the exact same thing happened.
Overvoltage, xentry alternator test failed with no other codes. 2nd new alternator worked fine. Maybe Bosch manufacturing defect.
Wiring harness or ECU issues are definitely on my mind though. Considering everything I've done at this point, I have low expectations.
Also the shop's owner has a W204 C63 where the exact same thing happened.
Overvoltage, xentry alternator test failed with no other codes. 2nd new alternator worked fine. Maybe Bosch manufacturing defect.
Wiring harness or ECU issues are definitely on my mind though. Considering everything I've done at this point, I have low expectations.
Your MBW friends will help you collectively get back and stay on the road.
Practice setting up IC workshop menu to read voltage + amperage while driving. Below 12.3V is troubles.
Last edited by CaliBenzDriver; Jun 3, 2025 at 05:04 PM.
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
Okay I really need to figure out a gameplan here....
Shop states:
"Your second alternator is still failing the testing using Xentry, the charging voltage looks abnormal still to me as well bouncing between 13 & 15.3 repeatedly. Faults are still logging on cylinder 7, and camshaft readings are the same. Something is not happy electrically and I do not have any answers as to what is causing it yet. Possibly a bad ground somewhere, possibly two bad alternators in a row, possibly a canbus communication issue in the car."
What is left? Does it make sense to test grounds > test battery cables > swap known good ECU?
I can't keep throwing money at parts and diagnostics and making no progress. But electrical stuff definitely scares me a bit working on it personally.
Edit:
Actually on second thought. Maybe it's more likely the electrical issue is alternator specific as they're not seeing any other signs of grounding or battery issues.
So what about checking the alternator connector, maybe a wiggle test to see if voltage is affected? > Check resistance on LIN bus wire? > check resistance on battery current sensor > voltage sense wire > battery temperature sensor?
I'm not sure. Just spit balling here.
Shop states:
"Your second alternator is still failing the testing using Xentry, the charging voltage looks abnormal still to me as well bouncing between 13 & 15.3 repeatedly. Faults are still logging on cylinder 7, and camshaft readings are the same. Something is not happy electrically and I do not have any answers as to what is causing it yet. Possibly a bad ground somewhere, possibly two bad alternators in a row, possibly a canbus communication issue in the car."
What is left? Does it make sense to test grounds > test battery cables > swap known good ECU?
I can't keep throwing money at parts and diagnostics and making no progress. But electrical stuff definitely scares me a bit working on it personally.
Edit:
Actually on second thought. Maybe it's more likely the electrical issue is alternator specific as they're not seeing any other signs of grounding or battery issues.
So what about checking the alternator connector, maybe a wiggle test to see if voltage is affected? > Check resistance on LIN bus wire? > check resistance on battery current sensor > voltage sense wire > battery temperature sensor?
I'm not sure. Just spit balling here.
Last edited by ZackaSnack; Jun 3, 2025 at 07:42 PM.
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)
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
Would I be crazy to just cut my losses at this point? I could maybe sell it for $15-$18k as-is? I'll have about spent that much in total (not including the cost of the car itself, which I vastly overpaid for) by the time I get it sorted... Maybe go back to Audi/VW group cars after my experience with this car.
I keep thinking I'm close, then just to realize there's still so many steps to maybe have a chance at uncovering another $1000 in fixes.
I keep thinking I'm close, then just to realize there's still so many steps to maybe have a chance at uncovering another $1000 in fixes.
Last edited by ZackaSnack; Jun 3, 2025 at 08:43 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
3x BAD ALT.
Okay I really need to figure out a gameplan here....
Shop states:
"Your second alternator is still failing the testing using Xentry, the charging voltage looks abnormal still to me as well bouncing between 13 & 15.3 repeatedly. Faults are still logging on cylinder 7, and camshaft readings are the same. Something is not happy electrically and I do not have any answers as to what is causing it yet. Possibly a bad ground somewhere, possibly two bad alternators in a row, possibly a canbus communication issue in the car."
What is left? Does it make sense to test grounds > test battery cables > swap known good ECU?
I can't keep throwing money at parts and diagnostics and making no progress. But electrical stuff definitely scares me a bit working on it personally.
Edit:
Actually on second thought. Maybe it's more likely the electrical issue is alternator specific as they're not seeing any other signs of grounding or battery issues.
So what about checking the alternator connector, maybe a wiggle test to see if voltage is affected? > Check resistance on LIN bus wire? > check resistance on battery current sensor > voltage sense wire > battery temperature sensor?
I'm not sure. Just spit balling here.
Shop states:
"Your second alternator is still failing the testing using Xentry, the charging voltage looks abnormal still to me as well bouncing between 13 & 15.3 repeatedly. Faults are still logging on cylinder 7, and camshaft readings are the same. Something is not happy electrically and I do not have any answers as to what is causing it yet. Possibly a bad ground somewhere, possibly two bad alternators in a row, possibly a canbus communication issue in the car."
What is left? Does it make sense to test grounds > test battery cables > swap known good ECU?
I can't keep throwing money at parts and diagnostics and making no progress. But electrical stuff definitely scares me a bit working on it personally.
Edit:
Actually on second thought. Maybe it's more likely the electrical issue is alternator specific as they're not seeing any other signs of grounding or battery issues.
So what about checking the alternator connector, maybe a wiggle test to see if voltage is affected? > Check resistance on LIN bus wire? > check resistance on battery current sensor > voltage sense wire > battery temperature sensor?
I'm not sure. Just spit balling here.
Now what are the likelyness of having three bad alternators in a row ?? less than slim.
You can cut down all that madness in 1mn with ALT--LIN. You'll get ALT in self-regulating mode. This is experimental and you've noted your chassis has seen high voltage way above 14.1V.
What I think is happening is the GND references of ECU are bad. Read good Bosch ECU but bad MB wiring.
MB factory paints GND posts then has standard rain swamp footwell area inspect that.
IN A NUTSHELL: 14.1V is nearly the prefect fix except ECU wiring and/or CAN networking will still be what it is.
That needs to be worked on without parts-canon...
I personally don't think a new ECU will help one bit. The voltage chaos is a network disruption centered on CGW. New CGW gets soft-crash, no need to replace it either.
I could be wrong... there may be a specific fix for this voltage chaos - Normally MB replaces new AGM Batteries - I only came up with experimental ALT-LIN shortcut to disable normal voltage swings.
Here you have a variant with a few different attributes.
Professional shop is most likely going by book procedures. Let's see.
Last edited by CaliBenzDriver; Jun 3, 2025 at 08:51 PM.
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
this us exactly what I wrote here in #184.
Now what are the likelyness of having three bad alternators in a row ?? less than slim.
You can cut down all that madness in 1mn with ALT--LIN. You'll get ALT in self-regulating mode. This is experimental and you've noted your chassis has seen high voltage way above 14.1V.
What I think is happening is the GND references of ECU are bad. Read good Bosch ECU but bad MB wiring.
MB factory paints GND posts then has standard rain swamp footwell area inspect that.
IN A NUTSHELL: 14.1V is nearly the prefect fix except ECU wiring and/or CAN networking will still be what it is.
That needs to be worked on without parts-canon...
I personally don't think a new ECU will help one bit. The voltage chaos is a network disruption centered on CGW. New CGW gets soft-crash, no need to replace it either.
I could be wrong... there may be a specific fix for this voltage chaos - Normally MB replaces new AGM Batteries - I only came up with experimental ALT-LIN shortcut to disable normal voltage swings.
Here you have a variant with a few different attributes.
Professional shop is most likely going by book procedures. Let's see.
Now what are the likelyness of having three bad alternators in a row ?? less than slim.
You can cut down all that madness in 1mn with ALT--LIN. You'll get ALT in self-regulating mode. This is experimental and you've noted your chassis has seen high voltage way above 14.1V.
What I think is happening is the GND references of ECU are bad. Read good Bosch ECU but bad MB wiring.
MB factory paints GND posts then has standard rain swamp footwell area inspect that.
IN A NUTSHELL: 14.1V is nearly the prefect fix except ECU wiring and/or CAN networking will still be what it is.
That needs to be worked on without parts-canon...
I personally don't think a new ECU will help one bit. The voltage chaos is a network disruption centered on CGW. New CGW gets soft-crash, no need to replace it either.
I could be wrong... there may be a specific fix for this voltage chaos - Normally MB replaces new AGM Batteries - I only came up with experimental ALT-LIN shortcut to disable normal voltage swings.
Here you have a variant with a few different attributes.
Professional shop is most likely going by book procedures. Let's see.
If there was a ground issue, wouldn't I be seeing other electrical issues that aren't just limited to some odd camshaft position angles, a single cylinder having very minor misfires, and Xentry testing the alternator as bad? That's effectively all we have to go off of right now, short of all the other parts I've replaced and ruled out at this point.
Last edited by ZackaSnack; Jun 3, 2025 at 08:56 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
VOLTAGE REPAIR DECISIONS
Can you elaborate again on ALT--LIN? What is the action here exactly? Just turning on the headlights?
If there was a ground issue, wouldn't I be seeing other electrical issues that aren't just limited to some odd camshaft position angles, a single cylinder having very minor misfires, and Xentry testing the alternator as bad? That's effectively all we have to go off of right now, short of all the other parts I've replaced and ruled out at this point.
If there was a ground issue, wouldn't I be seeing other electrical issues that aren't just limited to some odd camshaft position angles, a single cylinder having very minor misfires, and Xentry testing the alternator as bad? That's effectively all we have to go off of right now, short of all the other parts I've replaced and ruled out at this point.
-- HL:ON here may not help because 15.x voltage is too high. ECU is requesting wrong voltage.
-- ALT-LIN:OUT should deliver 14.1v with self-regulation.
> The bottom line is ....
-- we can well get self-regulated voltage
-- but knowing what's causing chaos around ECU signals would be normal repair.
Last edited by CaliBenzDriver; Jun 3, 2025 at 10:39 PM.
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From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
Normally I'd throw a SAM (its basically a fusebox) at something like this at the owners request and I've seen it work but you'd have to have multiple modules going down to really see a benefit from that. I can see it being ECU.
I think you gotta find another shop thats very good at MB, where have you gone so far?
I'm seeingMercedes Garage
Performance Motors BMW, Mercedes Benz, Land Rover, Jaguar, Audi, Volkswagen, Mini, Volvo, Porsche, Subaru service and repair
EuroCar Service
I figure youre at least at one or two of these. It's fixeable I'm just too stupid to get into anything this deep. I'd get on the phone and put a bounty on this
I think you gotta find another shop thats very good at MB, where have you gone so far?
I'm seeing
Mercedes Garage
Performance Motors BMW, Mercedes Benz, Land Rover, Jaguar, Audi, Volkswagen, Mini, Volvo, Porsche, Subaru service and repair
and
EuroCar Service
I figure youre at least at one or two of these. It's fixeable I'm just too stupid to get into anything this deep. I'd get on the phone and put a bounty on this
__________________
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Thread Starter
Member
Joined: Apr 2025
Posts: 137
Likes: 40
From: Seattle
2010 W212 E63 (M156)
Normally I'd throw a SAM (its basically a fusebox) at something like this at the owners request and I've seen it work but you'd have to have multiple modules going down to really see a benefit from that. I can see it being ECU.
I think you gotta find another shop thats very good at MB, where have you gone so far?
I'm seeingPerformance Motors BMW, Mercedes Benz, Land Rover, Jaguar, Audi, Volkswagen, Mini, Volvo, Porsche, Subaru service and repair
I think you gotta find another shop thats very good at MB, where have you gone so far?
I'm seeing
Mercedes Garage
Performance Motors BMW, Mercedes Benz, Land Rover, Jaguar, Audi, Volkswagen, Mini, Volvo, Porsche, Subaru service and repair
and
EuroCar Service
I figure youre at least at one or two of these. It's fixeable I'm just too stupid to get into anything this deep. I'd get on the phone and put a bounty on thisI originally wanted to take it back to Schmidt Automotive but they haven't been responsive.
There's a couple of other Mercedes specialists nearby that aren't just general Euro shops:
- Automeister II - I've talked to them on separate occasions and both times I felt they seemed a bit arrogant. The owner was insistent that my car has a torque converter transmission (the 2010 E63 has the MCT...). This was back when I was still exploring the possibility of my issue being something with the transmission solenoids.
- Mercedes Garage - This is part of a larger dealer (Park Place) that sells mostly high-end luxury and exotics. I've not yet spoke to them specifically but have had work done at one of their other businesses and I suspect their costs will be very high. I've also seen on their Service page they only install Mercedes genuine parts.
You might be right about taking it to another shop at this point though. Signature Independent has been reasonable though and fairly communicative. Although I realize now that most of their clients are BMW. I may try to follow-up with Schmitt Automotive again... Downside is that all these shops are like an hour's drive away... But I need to get the drama queen back on the road to make all my expenses worth it..
Last edited by ZackaSnack; Jun 4, 2025 at 12:26 AM.
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Joined: Apr 2021
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From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
Dude if a DEALER could prevent a $30,000 sunk cost financial L of this magnitude I'd be getting pretty desperate
Just do me a favor and sink 30k into some ETF's so we can recover the cost of this some day. That or start churning credit card offers lol. But yeah maybe we get into 997's after this
Just do me a favor and sink 30k into some ETF's so we can recover the cost of this some day. That or start churning credit card offers lol. But yeah maybe we get into 997's after this
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Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Joined: Nov 2016
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Can you elaborate again on ALT--LIN? What is the action here exactly? Just turning on the headlights?
If there was a ground issue, wouldn't I be seeing other electrical issues that aren't just limited to some odd camshaft position angles, a single cylinder having very minor misfires, and Xentry testing the alternator as bad? That's effectively all we have to go off of right now, short of all the other parts I've replaced and ruled out at this point.
If there was a ground issue, wouldn't I be seeing other electrical issues that aren't just limited to some odd camshaft position angles, a single cylinder having very minor misfires, and Xentry testing the alternator as bad? That's effectively all we have to go off of right now, short of all the other parts I've replaced and ruled out at this point.
). You just disconnect it and let it hang. You will get a DTC (no CEL), but it seems you like to collect them anyway. You'll know the DTC is that the ECU has lost communication with the alternator. The result is a very stable 14.1V when running.
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Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
GOOD THINGS BETTER
It's simple. There is a single wire (not cable) on the back of the alternator that allows the ECU to communicate with it and do some other stuff ().
You just disconnect it and let it hang. You will get a DTC (no CEL), but it seems you like to collect them anyway.
You'll know the DTC is that the ECU has lost communication with the alternator.
The result is a very stable 14.1V when running.
).You just disconnect it and let it hang. You will get a DTC (no CEL), but it seems you like to collect them anyway.
You'll know the DTC is that the ECU has lost communication with the alternator.
The result is a very stable 14.1V when running.
I don't think "ALT-LIN" (**) "cherry on a good cake" is a pass to skip troubleshooting the ECU requesting 15.xV. from 3 different alternators.
OP is getting over 15.xVolts... there's more to his voltage issue (poor GND circuits wiring). No evidence of bad module a REBOOT can't sanitize.
My honest advice is not to rush at swaping most expensive parts nor the cheapest shortcut fixes without drilling down to what's wrong.
Loosing power while driving is not the way to repairs.
🤞
(**): ALT-LIN shortcut:
--> is a fixed 14.1V experimentation for reducing low-voltage swings and yoyo drain-by-driving.
All combined it disables experimentally the whole [11.x to 14.9V] chaos. Associated steps Reboot/Float are best included.
-|- Higher voltage is a distinct disfunction: 70% likely ECU footwell GND connections.
the footwell fix/, inspection can take 10mn rather than chancing further higher voltage spike.
What's clear here is the lack of EFFECTIVE HELP FROM EXISTING TECHNOLOGY. Even MB Dealer use lucky parts-canon rather than "guided troubleshooting" - Troubleshooting recent EV is the same crap-shout... ouch!
Pros pay for a service to fix cars. IDENTIFIX runs a database of all the mfg planted bugs that fail in every specific car.
Absolutely no need for run around:
could not reproduce ....
you're the first one...
we don't know...
professional grade repair database
Last edited by CaliBenzDriver; Jun 4, 2025 at 11:09 PM.
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From: Seattle
2010 W212 E63 (M156)
What are people’s thoughts on it being safe to drive 20 miles with the 14-15V fluctuations? Should I just get it towed or maybe do the voltage alt-lin thing first?
I plan to take it to back to Schmitt Automotive (they mainly work on Mercedes with a lot of M156 and AMG experience) on Monday if the current shop doesn’t make any real progress by EOD Friday.
I plan to take it to back to Schmitt Automotive (they mainly work on Mercedes with a lot of M156 and AMG experience) on Monday if the current shop doesn’t make any real progress by EOD Friday.
