C250 CGI petrol engine management light

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ash1212002

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Aug 9, 2015
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W204 c250 cgi facelift petrol 2011
Upon completing the NC500 which was fantastic I must say, I would definitely would recommend it.

If anyone is considering doing the route and is seeking advice/tips drop me a message, I'll be more than happy to help :)

We Drove just over 1400 miles in a week!

Lucky for me, as soon as I got off the motorway and 5 minutes from our stop off, the engine management light appeared, no warning message on the dash, just the orange engine symbol appeared

Quickly pulled over on a side road, the car I can best describe was shaking/vibrating at idle when revving the engine it increased, also appeared to be lacking or struggling for power

Switched off the engine and restarted the car drove for 5 minutes to get to our destination and the light didn't reappear

I'll be driving 120 miles to return home, so conscious of the engine management light appearing again.

Any ideas what it could be? Anything I can check?

W204 facelift C250 CGI auto saloon, 47k

Cheers
 
It could be anything.... get yourself an iCarsoft MB v2.0 and read the codes.

Once you've done that, make a note of the fault codes, delete them, drive the car and see if any of the faults return.
 
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On another note, your M271 engine is prone to premature timing gear failure, I doubt that the EML is related to this (the timing gear failure will usually be accompanied by rough idle etc), but it's good to keep this in mind.
 
It could be anything.... get yourself an iCarsoft MB v2.0 and read the codes.

Once you've done that, make a note of the fault codes, delete them, drive the car and see if any of the faults return.

I have a code reader but its at home :doh: I'll have to keep an eye on the dash and take a gamble and drive it 120 miles to get home
 
I have a code reader but its at home :doh: I'll have to keep an eye on the dash and take a gamble and drive it 120 miles to get home

You need a code reader that can read MB-specific codes.... a generic OBDII scanner won't do.
 
You need a code reader that can read MB-specific codes.... a generic OBDII scanner won't do.

Yep the one that was given to me by a friend does read MB codes too :)
 
The CGI-engine is very touchy when it comes to timing chain EML.
The tolerance is narrow. If a rattle is heard then the EML must (IMHO) have been
on for quite some time. The vehicles I have heard of having timing chain out-of-tolerance
have had mileages of about 160.000 kms.

But I have seen large deposits of soot on the end of the exhaust system
on several turbo CGI-equipped vehicles. Possibly related to turbo bearing play
that allows engine oil to leak out in small quantities.

Mercedes have had problems with the
a banjo-bolt connecting the engine oil to the turbo bearings. When stopped,
the oil pressure is still substantial, and when the the engine is restarted,
there is a cloud of smoke behind the car emanating from
engine oil having leaked out into the turbo.

There is a fix for this, a redesigned
bolt with a small pressure sensitive valve in it. The bolt is not expenceive
but the work envolved in changing it (at least in my old C207) is said to take an hour or so
since some parts will have to be removed in order to gain access.

Having small fingers and with some patience, it is possible to do the change
in less than 10 minutes...
 
On another note, your M271 engine is prone to premature timing gear failure, I doubt that the EML is related to this (the timing gear failure will usually be accompanied by rough idle etc), but it's good to keep this in mind.

Reading again the symptoms you described, timing gear issue cannot be ruled-out.... I know this isn't what you wanted to hear, but I wouldn't drive the car until this was eliminated. Do you have Mobilo cover?
 
Unfortunately I do not have Mobilo cover or any sort of cover! To date I've never broken down!

I've just drove 20 minutes locally, the EML hasn't returned and the engine appears to be running fine, no rough running and idling fine
 
Drove back home 120 miles yesterday the EML didn't come up thank God.

I've plugged it in this morning and the fault code is
P0301 Code: Cylinder 1 Misfire Detected, looks like it may have been a temp fault rather than a permanent fault?

I've cleared the fault, will drive the car over a few days and plug back into the diagnostics, but I'm guessing the fault will only re-register on the diagnostics machine if the EML light comes back on again?
 

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