Help diagnosing fault codes - lean fuel mixture- P201C-001 + P2029-002

[Hustler]

Hi Guys,

I randomly decided to plug in the MB Carsoft tool into the car and ran through the diagnostics.

It showed the following two fault codes as stored:

• P201C-001
  • Selfadaption of mixture formation, The mixture is too rich in the part load range. [P0172]

• P2029-002
  • Selfadaption of mixture formation at lean stop (Tendency of engine towards ‘rich’)

I have noticed it drinking a bit more fuel than usual (it's not fuel efficient anyways) and a many weeks ago I do recall seeing the check engine light which extinguished itself the following day. I also tried replacing the fuel filter a few weeks back but gave up as I couldn't remove the Clic-R clips and thought maybe the slight increase in fuel consumption was perhaps down to a slightly loose fuel line in the fuel filter after my failed attempt to remove the clip. This could of course have nothing to do with it and is just pure speculation on my part, but thought it's worth a mention in case.

Would be grateful for any advice as to what the issue may be.

Many thanks


Vehicle: 2003 C200 Kompressor, Coupe, 1.8L, Petrol, Manual
M271 Engine

 

[Oldspanners]

Hi Guys,

I randomly decided to plug in the MB Carsoft tool into the car and ran through the diagnostics.

It showed the following two fault codes as stored:

• P201C-001
  • Selfadaption of mixture formation, The mixture is too rich in the part load range. [P0172]

• P2029-002
  • Selfadaption of mixture formation at lean stop (Tendency of engine towards ‘rich’)

I have noticed it drinking a bit more fuel than usual (it's not fuel efficient anyways) and a many weeks ago I do recall seeing the check engine light which extinguished itself the following day. I also tried replacing the fuel filter a few weeks back but gave up as I couldn't remove the Clic-R clips and thought maybe the slight increase in fuel consumption was perhaps down to a slightly loose fuel line in the fuel filter after my failed attempt to remove the clip. This could of course have nothing to do with it and is just pure speculation on my part, but thought it's worth a mention in case.

Would be grateful for any advice as to what the issue may be.

Many thanks


Vehicle: 2003 C200 Kompressor, Coupe, 1.8L, Petrol, Manual
M271 Engine

Have a look at the live data for your fuel trims.
Have a look at this video, excellent explanation.

 

[mattkh]

Hi Guys,........ and thought maybe the slight increase in fuel consumption was perhaps down to a slightly loose fuel line in the fuel filter after my failed attempt to remove the clip.

Firstly, check the fuel line near the filter with the engine running to make sure it is not leaking.
Secondly, when was the pre-cat oxygen sensor last changed?

 

[LostKiwi]

How many miles has your car done. If it's 80k or more and the O2 sensor has never been changed it would be a good starting point.

 

[Steve@Avantgarde]

Nothing to do with filters or 02 sensors. Its a mixture tolerance issue. So I would be checking what controls that first. 271 engine so the the first part to check is the air pipe underneath the manifold, its probably spilt.

 

[Westheath]

Yep check for vacuum leaks, PCV system first.

 

[Kang Ah Peng]

I am using a C180K Year 2005
and my engine light is on.
After checking it shows 3 codes.
P202B-008,P2029-001,P201C-001.
I would like to know what is the problems.
Thank you.

 

[geri]

Hi Guys,

I randomly decided to plug in the MB Carsoft tool into the car and ran through the diagnostics.

It showed the following two fault codes as stored:

• P201C-001
  • Selfadaption of mixture formation, The mixture is too rich in the part load range. [P0172]
• P2029-002
  • Selfadaption of mixture formation at lean stop (Tendency of engine towards ‘rich’)

I have noticed it drinking a bit more fuel than usual (it's not fuel efficient anyways) and a many weeks ago I do recall seeing the check engine light which extinguished itself the following day. I also tried replacing the fuel filter a few weeks back but gave up as I couldn't remove the Clic-R clips and thought maybe the slight increase in fuel consumption was perhaps down to a slightly loose fuel line in the fuel filter after my failed attempt to remove the clip. This could of course have nothing to do with it and is just pure speculation on my part, but thought it's worth a mention in case.

Would be grateful for any advice as to what the issue may be.

Many thanks


Vehicle: 2003 C200 Kompressor, Coupe, 1.8L, Petrol, Manual
M271 Engine

Hi, any update for this error? I have a same 2 code for my c230

 

[oleks1992]

As above, check your pcv pipes under the airbox for splits

 

[Wales33]

Hi Guys,

I randomly decided to plug in the MB Carsoft tool into the car and ran through the diagnostics.

It showed the following two fault codes as stored:

• P201C-001
  • Selfadaption of mixture formation, The mixture is too rich in the part load range. [P0172]
• P2029-002
  • Selfadaption of mixture formation at lean stop (Tendency of engine towards ‘rich’)

I have noticed it drinking a bit more fuel than usual (it's not fuel efficient anyways) and a many weeks ago I do recall seeing the check engine light which extinguished itself the following day. I also tried replacing the fuel filter a few weeks back but gave up as I couldn't remove the Clic-R clips and thought maybe the slight increase in fuel consumption was perhaps down to a slightly loose fuel line in the fuel filter after my failed attempt to remove the clip. This could of course have nothing to do with it and is just pure speculation on my part, but thought it's worth a mention in case.

Would be grateful for any advice as to what the issue may be.

Many thanks


Vehicle: 2003 C200 Kompressor, Coupe, 1.8L, Petrol, Manual
M271 Engine

Hi Hustler
I had the same problem with the same engine, for a long time. Three weeks ago I changed the rear o2 sensor,( rear of the cat.) and my warning lights are out and on my iCarsoft. Ver2 MB no faults found. Hope this helps.

 

[Tony23]

I'm getting 2054-002 and 2029-001. I changed all vacuum hoses. On idle it reves up and down. If anyone can help it would be greatly appreciated