Engine management light ON in my C55T

[xavier]

Hi,
I was travelling last weekend on M4 and I had a message coming up to top up my oil (1 litre) when refueling. Ignored it as I had a full tank of petrol but after about 15 minutes my engine management light came on the dash. I stopped at next petrol station and topped up the oil by required amount. Nothing has changed and light stayed on.
I couldn't see or feel anything wrong with the car, it was driving as usual.
Next day when I was about to go and see my mechanic to check the car, light was gone after starting the engine. I thought that was something with the sensor maybe and car was faultless for another week (short 15 mins journeys only)
Today my wife range me to say that Engine management light came on again when she was returning home after 30 mins run on the motorway
Car is booked tomorrow with mechanic to plug it in and check what can be wrong but does anyone have an idea what might be wrong?
Any comments appreciated.
Thanks

 

[Twistedmind]

With out plug in star test, your pissing in the wind

Sent from my iPhone using MBClub UK

 

[xavier]

Some update
I was travelling a lot and my car was parked for few weeks but:
after connecting to computer I found out that engine is misfiring on 3 cylinders (1,6 & 7th).
All plugs looked old and but rusty so I have replaced them all. It was fine until I took it for longer run. After warming up and covering about 20 miles engine warning light came on again and I could feel that engine was not running on all cylinders
When attempting to return home vibrations were very bad so I pulled over.
When restarted light was still on, you could hear that something is wrong but at least vibrations dissapeared. My next course of action will be replacing HT leads.
Do you have any other suggestions what needs looking at?
Thanks in advance

 

[merc85]

I take it the oil level reads correct? if in doubt why not drop the oil and measure how much comes out?

Also what is a c55t?? (serious question)

 

[KeithJG]

My MB dealer told me that some owners still use the "T" for estate model.

I was asking just to check if mine was a W203 or a S203 and he said some call them "T" also!!!!!

 

[xavier]

It's estate

 

[xavier]

Oil should be ok as I have recently topped it up by required 1 litre

 

[BlackC55]

Some update I was travelling a lot and my car was parked for few weeks but: after connecting to computer I found out that engine is misfiring on 3 cylinders (1,6 & 7th). All plugs looked old and but rusty so I have replaced them all. It was fine until I took it for longer run. After warming up and covering about 20 miles engine warning light came on again and I could feel that engine was not running on all cylinders When attempting to return home vibrations were very bad so I pulled over. When restarted light was still on, you could hear that something is wrong but at least vibrations dissapeared. My next course of action will be replacing HT leads. Do you have any other suggestions what needs looking at? Thanks in advance

Stop throwing parts at it. Get it diagnosed properly. It will save you ££ I promise you.

 

[xavier]

Hi Black C55,
I will get it to mechanic and connected to computer first as always but as I suspect and feel it is misfiring again on few cylinders. If diagnostics will come back with same result as before (misfire on 1st, 6th & 7th cylinder) then my mechanic is suggesting changing HT leads on those cylinders.