Check Engine after Air Filter Replacement
11-15-2015, 02:51 PM
#1
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2009 ML350 4Matic
Check Engine after Air Filter Replacement
Hello,
I changed the air filters on my wife's 2009 ML350 yesterday and got a P0175 System Too Rich (Bank 2) code. The small hose going into the air box ended up being loose. I've got the same code again and about to drive to her to check things out.
The only think that wasn't perfect was that one of the filter boxes didn't screw down perfectly flush no matter how I positioned things. I don't remember if it was that way when I started.
I used a Mann Filter C 3698/3-2.
Any ideas?
Thanks
EDIT - Same code again. This time the hose was not loose. It does not seem that filter housing does not fit flush. It seems a little warped and there's a bit of a gap.
I changed the air filters on my wife's 2009 ML350 yesterday and got a P0175 System Too Rich (Bank 2) code. The small hose going into the air box ended up being loose. I've got the same code again and about to drive to her to check things out.
The only think that wasn't perfect was that one of the filter boxes didn't screw down perfectly flush no matter how I positioned things. I don't remember if it was that way when I started.
I used a Mann Filter C 3698/3-2.
Any ideas?
Thanks
EDIT - Same code again. This time the hose was not loose. It does not seem that filter housing does not fit flush. It seems a little warped and there's a bit of a gap.
Last edited by rfc1918; 11-15-2015 at 05:03 PM.
11-16-2015, 07:28 AM
#2
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The cover is not on correctly and is hanging up on something causing the MAF to malfunction. Just my guess but certainly a place to start.
11-16-2015, 09:00 AM
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I will check to make sure the cover is clicked properly into place.
Yes, the codes are P0172 and P0175. Would this mean there is an airflow restriction or escape (not enough airflow)?
After this happened a 2nd time, I removed everything again. The hoses were on correctly this time. My air box seems warped a bit. I can't screw down the bolts 100% in certain places and the alignment of the air filter cover is not perfect on assembly. I don't remember if it was that way to begin with. I was able to get it to fit better this time but it's still not perfect. Is the air filter assembly meant to have a 100% air tight seal?
Yes, the codes are P0172 and P0175. Would this mean there is an airflow restriction or escape (not enough airflow)?
After this happened a 2nd time, I removed everything again. The hoses were on correctly this time. My air box seems warped a bit. I can't screw down the bolts 100% in certain places and the alignment of the air filter cover is not perfect on assembly. I don't remember if it was that way to begin with. I was able to get it to fit better this time but it's still not perfect. Is the air filter assembly meant to have a 100% air tight seal?
P0172
System Too Rich (Bank 1)
Status of this DTC
Confirmed DTC
Engine state when the fault appeared
Freeze frame trouble code: P0172
Fuel system status 1: Closed loop
Fuel system status 2: Closed loop
Calculated load value: 40.0 %
Coolant temperature: 177 °F
Short term fuel % trim Bank 1: -10.9 %
Long term fuel % trim Bank 1: +7.0 %
Short term fuel % trim Bank 2: -8.6 %
Long term fuel % trim Bank 2: +10.2 %
Intake Manifold Pressure: 10.9 inHg
Engine RPM: 594 rpm
Vehicle speed: 0 mph
Timing advance: 7.5 °
Intake air temperature: 104 °F
Maf air flow: 0.76 lb/min
Absolute Throttle sensor position: 12.9 %
Secondary air status: Atmosphere / off
Time since engine start: 739 seconds
Commanded evaporative purge: 0.0 %
Fuel level input: 49.4 %
Barometric pressure: 29.8 inHg
Control module voltage: 14.135 Volt
Absolute load value: 28.2 %
Fuel/air commanded equivalence ratio: 0.999
Relative throttle position: 1.2 %
Ambient air temperature: 68 °F
Absolute throttle position B: 12.2 %
Accelerator pedal position D: 7.5 %
Accelerator pedal position E: 7.5 %
Commanded throttle actuator control: 1.6 %
System Too Rich (Bank 1)
Status of this DTC
Confirmed DTC
Engine state when the fault appeared
Freeze frame trouble code: P0172
Fuel system status 1: Closed loop
Fuel system status 2: Closed loop
Calculated load value: 40.0 %
Coolant temperature: 177 °F
Short term fuel % trim Bank 1: -10.9 %
Long term fuel % trim Bank 1: +7.0 %
Short term fuel % trim Bank 2: -8.6 %
Long term fuel % trim Bank 2: +10.2 %
Intake Manifold Pressure: 10.9 inHg
Engine RPM: 594 rpm
Vehicle speed: 0 mph
Timing advance: 7.5 °
Intake air temperature: 104 °F
Maf air flow: 0.76 lb/min
Absolute Throttle sensor position: 12.9 %
Secondary air status: Atmosphere / off
Time since engine start: 739 seconds
Commanded evaporative purge: 0.0 %
Fuel level input: 49.4 %
Barometric pressure: 29.8 inHg
Control module voltage: 14.135 Volt
Absolute load value: 28.2 %
Fuel/air commanded equivalence ratio: 0.999
Relative throttle position: 1.2 %
Ambient air temperature: 68 °F
Absolute throttle position B: 12.2 %
Accelerator pedal position D: 7.5 %
Accelerator pedal position E: 7.5 %
Commanded throttle actuator control: 1.6 %
11-16-2015, 09:14 AM
#5
Senior Member
I will check to make sure the cover is clicked properly into place.
Yes, the codes are P0172 and P0175. Would this mean there is an airflow restriction or escape (not enough airflow)?
After this happened a 2nd time, I removed everything again. The hoses were on correctly this time. My air box seems warped a bit. I can't screw down the bolts 100% in certain places and the alignment of the air filter cover is not perfect on assembly. I don't remember if it was that way to begin with. I was able to get it to fit better this time but it's still not perfect. Is the air filter assembly meant to have a 100% air tight seal?
Yes, the codes are P0172 and P0175. Would this mean there is an airflow restriction or escape (not enough airflow)?
After this happened a 2nd time, I removed everything again. The hoses were on correctly this time. My air box seems warped a bit. I can't screw down the bolts 100% in certain places and the alignment of the air filter cover is not perfect on assembly. I don't remember if it was that way to begin with. I was able to get it to fit better this time but it's still not perfect. Is the air filter assembly meant to have a 100% air tight seal?
Can you post a picture of your warped cover. Is it warped because of heat or other external cause...accident?
If so, stop typing and go to a dealer and get it ASAP replaced.
11-16-2015, 11:27 AM
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I'll also see if the check engine light comes back on today after tightening things up better yesterday.
11-16-2015, 11:40 AM
#7
Senior Member
Warped may be somewhat of an overstatement. I should have said the air filter cover does not fit flush against the air box assembly. Although I think my filters are the right OEM part numbers, I may try to screw down the cover with the filters removed to see if closes flush.
I'll also see if the check engine light comes back on today after tightening things up better yesterday.
I'll also see if the check engine light comes back on today after tightening things up better yesterday.
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11-18-2015, 12:37 PM
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Same codes came back. I have an appointment with a mechanic tomorrow for something else. I will report back the solution for anyone else that sees this. I'm surprised an air filter change could lead to something like this.
Thanks for the tips everyone.
Thanks for the tips everyone.
12-23-2015, 10:56 AM
#9
airbox is not seated on MAF sensor properly.
It could be that the MAF sensor is and Airfilter box is not seated together properly causing a leak:
Check this video to see how it's done: It can be tricky if the MAF sensor is also loose and not correctly connected.
Check this video to see how it's done: It can be tricky if the MAF sensor is also loose and not correctly connected.
