C63 AMG: P2188 & P2190 - Rich at Idle, EVAP/Purge Valve Suspect
Thread Starter
Newbie
Joined: Mar 2023
Posts: 11
Likes: 16
From: Melbourne, Australia
2009 AMG C63
C63 AMG: P2188 & P2190 - Rich at Idle, EVAP/Purge Valve Suspect
Hi guys,
I'm working through a rich running issue on my C63 AMG (M156 engine) and was hoping for some advice or insights from anyone who has experience similar problems.
I'm currently dealing with two fault codes:
P2188: System Too Rich at Idle (Bank 1)
P2190: System Too Rich at Idle (Bank 2)
Symptoms include noticeably rich fuel trims at idle (STFT and LTFT both negative), but the car seems to run fine under load. Here's what I've done so far:
MAF sensor has been cleaned, and readings are slightly high at idle but seem normal at higher RPMs.
Oxygen sensors are functioning normally, with expected fluctuations pre-cat and steady readings post-cat.
Given the rich condition only occurs at idle, I'm starting to suspect the EVAP purge valve might be stuck open, allowing unmetered fuel vapors into the intake. This would explain the rich mixture at low RPMs, where the engine is most sensitive to extra fuel.
Has anyone else had similar issues with the P2188/P2190 codes on their AMG? Would you recommend focusing on the EVAP system or is it worth digging deeper into the MAF sensor?
I'm currently running an EVAP system test with my OBDII to confirm the purge valve is functioning properly. Any tips on what to watch for during this test?
Appreciate any insights you all might have!
I'm working through a rich running issue on my C63 AMG (M156 engine) and was hoping for some advice or insights from anyone who has experience similar problems.
I'm currently dealing with two fault codes:
P2188: System Too Rich at Idle (Bank 1)
P2190: System Too Rich at Idle (Bank 2)
Symptoms include noticeably rich fuel trims at idle (STFT and LTFT both negative), but the car seems to run fine under load. Here's what I've done so far:
MAF sensor has been cleaned, and readings are slightly high at idle but seem normal at higher RPMs.
Oxygen sensors are functioning normally, with expected fluctuations pre-cat and steady readings post-cat.
Given the rich condition only occurs at idle, I'm starting to suspect the EVAP purge valve might be stuck open, allowing unmetered fuel vapors into the intake. This would explain the rich mixture at low RPMs, where the engine is most sensitive to extra fuel.
Has anyone else had similar issues with the P2188/P2190 codes on their AMG? Would you recommend focusing on the EVAP system or is it worth digging deeper into the MAF sensor?
I'm currently running an EVAP system test with my OBDII to confirm the purge valve is functioning properly. Any tips on what to watch for during this test?
Appreciate any insights you all might have!
Member
Joined: Apr 2021
Posts: 87
Likes: 44
AMG GTs & w204 C63
Hey did you ever solve it? Having same issue. Injectors are new, sparks are new, no leak at the manifold gasket, MAFs seem fine. Everything sealed and seated correctly.
idling jumping from 500rpm to 700rpm. Under load everything is fine.
P2188 & P2190
idling jumping from 500rpm to 700rpm. Under load everything is fine.
P2188 & P2190
Thread Starter
Newbie
Joined: Mar 2023
Posts: 11
Likes: 16
From: Melbourne, Australia
2009 AMG C63
Did I solve the P2188 & P2190 issue? Yes I did........eventually. I did almost the same as you. Replaced injectors. Was just about ready to buy 2 new MAF sensors at $400 each but didn't. I did find a small air leak at the intake. Plugged that but still didn't go away. Finaly a friend of a friend told me to replace the "Fuel Pump Control Module". So I ordered one, installed it (5 mins) cleared the fault codes and they havent come back.
Newbie
Joined: May 2025
Posts: 1
Likes: 0
S63 2008
P2188, P2190 M156
Hello Guys, I am facing this issue since last 6 months the car is shaking in idle and the exhaust is loud.
I went to the dealer and it turned out that the intake plate was cracked and i replaced it.
after that i had a check engine light and when i checked it showed P2190 and the dealer told that its from the MAF so i cleaned both of them and now i am having two coded P2190 and P2188 and the live data for self adaptation shows that both right and left is -6.
And the engine rattles when is start it when its warm and its little bit shaking in idle.
please help
I went to the dealer and it turned out that the intake plate was cracked and i replaced it.
after that i had a check engine light and when i checked it showed P2190 and the dealer told that its from the MAF so i cleaned both of them and now i am having two coded P2190 and P2188 and the live data for self adaptation shows that both right and left is -6.
And the engine rattles when is start it when its warm and its little bit shaking in idle.
please help
Thread Starter
Newbie
Joined: Mar 2023
Posts: 11
Likes: 16
From: Melbourne, Australia
2009 AMG C63
Hey mate, I’ve been through this exact headache with my own M156. If you’re still getting P2188 and P2190 after replacing the intake plate and cleaning the MAFs, I’d suggest checking the fuel pump pressure control module — it’s in the boot, right side, near the battery. These modules can fail or send incorrect pressure to the rail, making the car run rich at idle and triggering those codes. It won’t always throw a direct fault for the module itself — just symptoms like rich mixture and rough idle.
Remove it, check it with a multimeter — resistance and continuity — and compare values across the pins. If it’s faulty, it won’t regulate pressure properly, even if the pump is fine. I replaced mine and it cleared both codes straight away. Let me know how you go.
Remove it, check it with a multimeter — resistance and continuity — and compare values across the pins. If it’s faulty, it won’t regulate pressure properly, even if the pump is fine. I replaced mine and it cleared both codes straight away. Let me know how you go.
Newbie
Joined: Feb 2025
Posts: 1
Likes: 0
Hi friend, I know this is old, but now I have the same two codes on my ml63. Do you know what caused it?
Member
Joined: Oct 2016
Posts: 172
Likes: 31
C63 AMG SEDAN 2013 (PP)
Hi guys,
I'm working through a rich running issue on my C63 AMG (M156 engine) and was hoping for some advice or insights from anyone who has experience similar problems.
I'm currently dealing with two fault codes:
P2188: System Too Rich at Idle (Bank 1)
P2190: System Too Rich at Idle (Bank 2)
Symptoms include noticeably rich fuel trims at idle (STFT and LTFT both negative), but the car seems to run fine under load. Here's what I've done so far:
MAF sensor has been cleaned, and readings are slightly high at idle but seem normal at higher RPMs.
Oxygen sensors are functioning normally, with expected fluctuations pre-cat and steady readings post-cat.
Given the rich condition only occurs at idle, I'm starting to suspect the EVAP purge valve might be stuck open, allowing unmetered fuel vapors into the intake. This would explain the rich mixture at low RPMs, where the engine is most sensitive to extra fuel.
Has anyone else had similar issues with the P2188/P2190 codes on their AMG? Would you recommend focusing on the EVAP system or is it worth digging deeper into the MAF sensor?
I'm currently running an EVAP system test with my OBDII to confirm the purge valve is functioning properly. Any tips on what to watch for during this test?
Appreciate any insights you all might have!
I'm working through a rich running issue on my C63 AMG (M156 engine) and was hoping for some advice or insights from anyone who has experience similar problems.
I'm currently dealing with two fault codes:
P2188: System Too Rich at Idle (Bank 1)
P2190: System Too Rich at Idle (Bank 2)
Symptoms include noticeably rich fuel trims at idle (STFT and LTFT both negative), but the car seems to run fine under load. Here's what I've done so far:
MAF sensor has been cleaned, and readings are slightly high at idle but seem normal at higher RPMs.
Oxygen sensors are functioning normally, with expected fluctuations pre-cat and steady readings post-cat.
Given the rich condition only occurs at idle, I'm starting to suspect the EVAP purge valve might be stuck open, allowing unmetered fuel vapors into the intake. This would explain the rich mixture at low RPMs, where the engine is most sensitive to extra fuel.
Has anyone else had similar issues with the P2188/P2190 codes on their AMG? Would you recommend focusing on the EVAP system or is it worth digging deeper into the MAF sensor?
I'm currently running an EVAP system test with my OBDII to confirm the purge valve is functioning properly. Any tips on what to watch for during this test?
Appreciate any insights you all might have!
Trending Topics
Newbie
Joined: Aug 2025
Posts: 1
Likes: 0
2012 C63 AMG - Aus RHD
Having the same codes and symptons, can somone give me a hand as to where exactly the Fuel Pump Control Module is, I have all 3 carpet trim panels out in the boot and cannot for the life of me find it. Prior guy above suggested it was in the boot near battery... pls help haha.
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Member
Joined: Oct 2016
Posts: 172
Likes: 31
C63 AMG SEDAN 2013 (PP)
Hey mate, I’ve been through this exact headache with my own M156. If you’re still getting P2188 and P2190 after replacing the intake plate and cleaning the MAFs, I’d suggest checking the fuel pump pressure control module — it’s in the boot, right side, near the battery. These modules can fail or send incorrect pressure to the rail, making the car run rich at idle and triggering those codes. It won’t always throw a direct fault for the module itself — just symptoms like rich mixture and rough idle.
Remove it, check it with a multimeter — resistance and continuity — and compare values across the pins. If it’s faulty, it won’t regulate pressure properly, even if the pump is fine. I replaced mine and it cleared both codes straight away. Let me know how you go.
Remove it, check it with a multimeter — resistance and continuity — and compare values across the pins. If it’s faulty, it won’t regulate pressure properly, even if the pump is fine. I replaced mine and it cleared both codes straight away. Let me know how you go.
Can you please post a photo of the part and where is located?
Thanks
Member
Joined: Oct 2016
Posts: 172
Likes: 31
C63 AMG SEDAN 2013 (PP)
Did I solve the P2188 & P2190 issue? Yes I did........eventually. I did almost the same as you. Replaced injectors. Was just about ready to buy 2 new MAF sensors at $400 each but didn't. I did find a small air leak at the intake. Plugged that but still didn't go away. Finaly a friend of a friend told me to replace the "Fuel Pump Control Module". So I ordered one, installed it (5 mins) cleared the fault codes and they havent come back.
Can you please post pics of the part and the location? That will be very helpful
thanks
