Yellow engine diagnostic indicator lamp is lit while the engine is running

[echo200]

Vehicle: W203 C200K, petrol, '55' plate.

Other than the warning lamp, the car is running normally. There are no other obvious symptoms, such as engine misfire.

The manual suggests three possible malfunctions, viz.

1. Fuel injection system
2. Exhaust system
3. Ignition system

If it turns out to be the exhaust system, presumably I could be looking at a broken catalytic converter in which case any advice on sourcing a replacement (+ cost of fitting) would be appreciated.

 

[Cyprus]

This happened to me very recently (couple of weeks back). The car was running perfectly in every respect. Took it to my local main dealer to be checked and it turned out to be a dodgy knock-sensor playing up. Fortunately in my case it was replaced and sorted under warranty.

The warning light could signify one of many things, I could only suggest getting it diagnosed at a dealer or reputable indie.

.

 

[drmw]

Vehicle: W203 C200K, petrol, '55' plate.

Other than the warning lamp, the car is running normally. There are no other obvious symptoms, such as engine misfire.

The manual suggests three possible malfunctions, viz.

1. Fuel injection system
2. Exhaust system
3. Ignition system

If it turns out to be the exhaust system, presumably I could be looking at a broken catalytic converter in which case any advice on sourcing a replacement (+ cost of fitting) would be appreciated.

as often as not if it all seems to be running ok, it's a dodgy O2 sensor. Unsure of MB prices, but even on my aston it was sub £100

 

[echo200]

Hopefully, you're right about the dodgy sensor. I only came up with the notion of a broken cat because of all the (insert swear word) potholes in my area!

Actually, I did a 30 mile round trip today without detecting anything out of the ordinary in terms of performance.

Regarding dealer prices, my local MB outfit quoted me £63 for recalibrating my slightly hysterical rain sensor. Perhaps, this is a chance to kill two birds with one stone?

 

[television]

My CPS just before it failed would put the lamp on.

 

[EmilysDad]

....

Regarding dealer prices, my local MB outfit quoted me £63 for recalibrating my slightly hysterical rain sensor. ...

Last year my wipers would only do stop or monsoon when set to auto. The sensor had come away from the screen (not sure how they should fixed to it) but a tiny blob of bluetack is still holding mine to the screen & the wipers work as expected. Remove the cover from below your rear view mirror & have a look

 

[Cyprus]

Hopefully, you're right about the dodgy sensor.

Actually, I did a 30 mile round trip today without detecting anything out of the ordinary in terms of performance.

Sounds very much the same situation to mine. Mine ran perfectly, with no detectable change in perfomance or operation of the car.

Hopefully yours could just be a sensor too, certainly a possibility.

(I always get a bit 'jumpy' when warning indicators come on though!! :Oops

 

[Crew]

I had the same, took it to a mb specialist sparky and he put it down to the o2 sensor, but not the sensor itself. Apparently it was a £7 rubber tube that runs along the back of the engine that had split.

 

[Stability]

Vehicle: W203 C200K, petrol, '55' plate.

Other than the warning lamp, the car is running normally. There are no other obvious symptoms, such as engine misfire.

The manual suggests three possible malfunctions, viz.

1. Fuel injection system
2. Exhaust system
3. Ignition system

If it turns out to be the exhaust system, presumably I could be looking at a broken catalytic converter in which case any advice on sourcing a replacement (+ cost of fitting) would be appreciated.

Its anything that would effect our beloved earth in polluting it beyond the legal specification.

 

[television]

Its anything that would effect our beloved earth in polluting it beyond the legal specification.

As I am a pensioner, I am allowed to exceed the limits:roll:

 

[Steve@Avantgarde]

The only thing I can say is, get it on STAR!!

 

[echo200]

The bill

Firstly, thanks for all the comments.

The fault has been diagnosed (cost £62.50) as an air leak from the manifold air hose. Parts have been costed at £10.90 + VAT.

Now for the bad news! In order to access the hose, the supercharger has to come out. This means a total labour charge of £348.70 + VAT.

The only good news is that at least the rain sensor has been recalibrated.

 

[echo200]

Second visit to the dealer required!

Picked up the car from the dealer today and, just as I got home, the engine diagnostic indicator lamp lit up! No choice but to take it back tomorrow.

I could say more, but the moderator would have to intervene!