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W212 Engine Management Light on

Spender400

New Member
Joined
Jul 28, 2022
Messages
1
Location
WARWICKSHIRE
Car
W212
Hi

I'm on a road trip through Europe in my 2012 w212. When my car passed through the Pyrenees into Spain I was ascending for about 40 mins and the descending on engine (automatic) and brakes for around 40 mins. During the descent I saw the EML light up and the car lost power when on the next incline. I pulled over and restarted and it moved OK for a while but then the issue recurred.

Got mobilo assist out as the car is serviced by Merc since new. Readout shows
P023628 BOOST PRESSSURE SENSOR MALFUNCTION
P029900 TURBO UNDERBOOST
P246309 DPF SOOT LEVEL NOT OK

Mobilo guy said he checked hoses and turbo readings were OK. EML was reset. Off we set on the next leg. Car EML was on within 10 mins and revs and speed kept low. Occasionally when started the car is like it's being towed by a donkey, but mostly runs okish.

My thoughts are to get mobilo out and get it into Merc for a fix. I'd welcome any thoughts on what the code combination might mean, or other ideas. Air temp here is 29c to 39c.

Thanks in advance
 
Sounds like dpf may be clogging up. I’d drive it at slightly higher revs than normal for say 20 min to half hour (2.5-3k) and maybe stick a bottle of cataclean in it, then drive it a bit more and then assess the scenario by sticking a code reader in it if the engine codes haven’t reset themselves by then.
 
Hello OP and welcome . 10 yars old and still being serviced by MB main dealers ! That might pay off on this occasion. I hope they sort it out.

PS . If you do put any type of additive in the tank (your choice) just don't tell anyone at MB that you did.
 
Could be a split boost pipe. A smoke test would prove this. (smoke injected to the inlet to see if it leaks out of any of the boost pipes. Had a similar thing on my S204.

It could throw up the codes you are seeing as the boost pressure would be low, the car would throw out a lot of soot and may clod the dpf slightly

But only a proper diagnosis would show the real issue. Hope you sort it
 

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