2014 SLK 250d AMG (R172) Engine Warning Light - Limp Mode

[BradMBZ]

Hope you can shed some light in order to choose direction please.

Limp mode with engine light sometimes on a morning after travelling a mile or so. Park up for a couple of hours and the light will remain on but will disappear after a longer period or overnight. Car performs normally after stopping engine when engine is up to temperature and restarted even though engine light is still on.

2 Fault Codes reported at recent service (46k Miles) P029900 & P00AF72 with some advice that Turbo will need replacing etc.

I have done some reading and so far faults point towards Boost Pressure Sensor or Turbo Boost Pressure Transducer Valve or Turbo itself (blades/Waste Gate/Diaphragm Valve) . I have changed Transducer Valve and this has not fixed the issue.

There are two Sensors that I can see which are a little confusing because sometimes they say they are the same. I have pictures of both.

1. On Air Intake - DC (light green text on silver) - A 006 153 97 2B. - 14-03-15 2D 21 - 0 261 230 190
2. Close to Transducer Valve - Bosch (white text on black) - 2111 08 T1 20623B - 0 261 230 439

Everything else on the car seems fine apart from occasional smell of oil.

Ultimately it would be great to know IF its a £1,400 replace or a £100 repair.

Many Thanks
Brad

 

[OneForTheRoad]

I've got a map sensor from my old om642 , your welcome to pop it in and see if things improve. I'm also near Durham.

I also own a diagnostic scanner I'd run on the car for you.


Green print is manifold pressure

White print is turbo boost pressure

 

[BradMBZ]

I've got a map sensor from my old om642 , your welcome to pop it in and see if things improve. I'm also near Durham.

I also own a diagnostic scanner I'd run on the car for you.


Green print is manifold pressure

White print is turbo boost pressure

Hi,

Many thanks for replying and the offer of help.

I had ordered the 2 parts just in case earlier in the week but being after to check after fitting using a scanner would be great please.

Did you have similar issues?

Many thanks again

Brad

 

[OneForTheRoad]

Hi,

Many thanks for replying and the offer of help.

I had ordered the 2 parts just in case earlier in the week but being after to check after fitting using a scanner would be great please.

Did you have similar issues?

Many thanks again

Brad

I did have limp home issues with a w219 CLS once , I swapped out a few parts until I found the culprit , I bought a scanner soon after , because buying parts and playing russian roulette isn't cost effective.

 

[BlackC55]

Its likely to be the boost pressure sensor. The one near the intake manifold. ONLY buy genuine MB for this part. Re-set all the adaptation data after fitting too. The codes are only 1/2 the information. Live data is the key and interpreting that data is the skill.

Often its best in this case with the 651 engine is to take it to a specialist with a Star to diagnose it in the correct manner. Every day of the week we have people (and other garages) getting in a muddle about what to replace and with what make part. So many generic code readers dont pull all the codes either.

 

[BradMBZ]

I did have limp home issues with a w219 CLS once , I swapped out a few parts until I found the culprit , I bought a scanner soon after , because buying parts and playing russian roulette isn't cost effective.

Thanks and totally agree with you - fine if one or two parts are cheap/easy to fit and normally the issue but a guessing game. Will keep you posted.

 

[BradMBZ]

Its likely to be the boost pressure sensor. The one near the intake manifold. ONLY buy genuine MB for this part. Re-set all the adaptation data after fitting too. The codes are only 1/2 the information. Live data is the key and interpreting that data is the skill.

Often its best in this case with the 651 engine is to take it to a specialist with a Star to diagnose it in the correct manner. Every day of the week we have people (and other garages) getting in a muddle about what to replace and with what make part. So many generic code readers dont pull all the codes either.

Thank you for your reply and fully agree with your take on position and advice (shame i'm in NE).
Had an X6 with same issues and garage strategy was to replace everything that it could be before then replacing the most expensive part Turbo - total bill £1,920.

I will look for local garages who have the Star and skill to use it. Guess you need a code reader/Star to Re-set adaptation data?

Will post results.