THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Emirdizlay · Post by **Emirdizlay** » 06 Feb 2021, 21:27

Hello, I have the same problem (p2177)
and I have same symptoms. Did you solve this problem ?

lancia58 · Post by **lancia58** » 07 Feb 2021, 17:31

Hi,

The whole thing started after I changed the HPF ( High Pressure Fuel Pump ) . At the beginning I didn't link between the new HPF and the fault. I now understand that this may be the source for the problem. I considering replacing it to a new one.

Good luck

Emirdizlay · Post by **Emirdizlay** » 07 Mar 2021, 20:16

Have you tried replacing the oxygen sensor ?
My car is at 140,000 km and the oxygen sensor has never changed. Do you think the faulty may be due to the oxygen sensor?

lancia58 · Post by **lancia58** » 10 Mar 2021, 04:21

Hi

I didn't try. I do not know if the oxygen sensor is the problem.

roelb · Post by **roelb** » 26 Aug 2023, 20:03

Sorry to bump an old post, but I was wondering if any of you guys ever resolved this issue? My C5 has the exact same problem, with both faults triggering only when the engine is idling and the car is atanding still.

lancia58 · Post by **lancia58** » 26 Sep 2023, 05:36

roelb wrote: ↑26 Aug 2023, 20:03 Sorry to bump an old post, but I was wondering if any of you guys ever resolved this issue? My C5 has the exact same problem, with both faults triggering only when the engine is idling and the car is atanding still.

Hi,

Two month ago I had to replace the brake amplifier ( brake booster ) since there was a vacuum leak ( I heard a hiss noise coming from the boster ). This leak is actually vacuum leak. After replacing it the problem is gone ( drove more than 2000km after replacing it ) . What strengthen that this is the problem is that the fault occurs when the car was stopped . I guess that this leak was always there but to a lesser degree so I didn't hear the hiss noise in teh cabin. I am not sure that this is was cure the fault , but it definitely sorted after I replaced the booster. Any way what is sure is that the problem is caused by a vacuum leak that can be elsewhere in the car.
Hope this helps

BR
Zohar

roelb · Post by **roelb** » 11 Jan 2024, 21:04

Thnx for the reply! I had a defective turbo just after posting this (bearings). While replacing the turbo I decided to replace the timing chain as well, as I already drained the oil out of the engine for the turbo replacement and I suspected timing might play a role here.

Problem did not reappear after that. So no clue as to what the exact cause was, but suspect that it might have been a timing issue. Still have some hesitation and sputtering between 2000 and 4000rpm (but no engine management failure). Inlet cleaning will next, and if that doesn't solve the issue, the high pressure fuel pump is the final suspect.

lancia58 · Post by **lancia58** » 13 Jan 2024, 19:55

Hi,

Inlet manifold cleaning make wonders.

Zohar

French Car Forum

THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.

Re: THP Engine fault P2177 - Mixture regulation fault : Mixture too lean.