Engine light comes on then off

[rosslyn]

Hi

My engine alert light came on 3 days ago, i was just about to ring up and bokk the car in for a check, and now its gone off

Any ideas

Cheers

Rosslyn

 

[rosslyn]

engine warning light

Hi All

My engine warning light came on 3 days ago, booked it in for a check and before i can take it in, its gone off now,

Any ideas

Cheers

Rosslyn

 

[OmniCognateNeutronRangler]

ok, you may not like this. Have you been anywhere near a tesco, morrisons or Asda petrol station in the last couple of weeks?

I had exactly the same on my car. The light came on for about 120 miles and then went out again. In my case it has been confirmed as fuel contamination. Ihave been quoted £1360 to fix it. Fortunately it looks like Tesco will pay for it.

IT MAY NOT BE THAT, but you should get it checked out.

check this thread:

http://forums.mercedesclub.org.uk/showthread.php?t=26014

and this

http://forums.mercedesclub.org.uk/showthread.php?t=25958

 

[television]

Hi

My engine alert light came on 3 days ago, i was just about to ring up and bokk the car in for a check, and now its gone off

Any ideas

Cheers

Rosslyn

It should be the MAF filter,expensive from MB circa £500 fitted or buy one from Bosch £60 + fitting ½ hour.

Contaminated petrol if you bought Tesco.

Malcolm

 

[rosslyn]

i got my local Lucas delealer to take a look as the MD cant fit me in for a week or so, anyway they checked the error and it states it is the oxygen sensors but after the cat which seems to suggest not the fuel problem any ideas any one before i book it in to the MD

 

[eric242340]

i got my local Lucas delealer to take a look as the MD cant fit me in for a week or so, anyway they checked the error and it states it is the oxygen sensors but after the cat which seems to suggest not the fuel problem any ideas any one before i book it in to the MD

Hi Rosslyn, if the 02 or oxegen sensors (no matter which one) turns the check engine light on, then there is an air/fuel ratio problem. These sensors, as pointed out by Malcolm on another thread work under extreme temperatures. However they very rarely go wrong. They are simply indicating that there is a problem. ie dont kill the messenger, and thats what an oxygen sensor is, a messenger. With BMW they do go wrong and give the wrong signals. But with Mercedes rarely. If its an after CAT sending this signal, then maybe the CAT has a problem. But this is only an assumption. Better to have a full diagnostic test done and go from there.;-)

 

[rosslyn]

Hi Eric

Thanks for the advise, i will get the local MD to check it out

cheers


Rosslyn

 

[OmniCognateNeutronRangler]

have a look at this post : http://forums.mercedesclub.org.uk/showthread.php?t=25958&page=6

I have included the report from the diagnostic gadget they ran on my car. Click on the image to see it full size. You will see that the results sound exactly the same as yours. Sadly, next to it you will see the bill. Mine is a V6 so has 4 O2 sensors, hence the price but if it is that it isn't going to be cheap.

The good news is if you did get duff fuel from Tesco they will pay to get the work done.

Check out www.tesco.com/petrol

btw, 2 of my sensors are after the cat and 2 are before. All 4 are showing errors.

 

[television]

i got my local Lucas delealer to take a look as the MD cant fit me in for a week or so, anyway they checked the error and it states it is the oxygen sensors but after the cat which seems to suggest not the fuel problem any ideas any one before i book it in to the MD

Fault code read outs need some understanding. Any CO2 sensor could be damaged from the contaminated fuel.
With read outs you have to do some thinking, this fault could still be the MAF filter. Mafs can clear on a new start,where as CO2 sensors would not.

Malcolm

 

[eric242340]

have a look at this post : http://forums.mercedesclub.org.uk/showthread.php?t=25958&page=6

I have included the report from the diagnostic gadget they ran on my car. Click on the image to see it full size. You will see that the results sound exactly the same as yours. Sadly, next to it you will see the bill. Mine is a V6 so has 4 O2 sensors, hence the price but if it is that it isn't going to be cheap.

The good news is if you did get duff fuel from Tesco they will pay to get the work done.

Check out www.tesco.com/petrol

btw, 2 of my sensors are after the cat and 2 are before. All 4 are showing errors.

If you accept the findings OK, but not all problems are related to the UK fuel problem.:-|

 

[OmniCognateNeutronRangler]

If you accept the findings OK, but not all problems are related to the UK fuel problem.:-|

completely agree. Difference is if it is related to fuel then in theory you can get the work done on Tesco's ticket rather than your own.

It does seem very coincidental though if it's not the fuel problem. Having said that, as I said on the other thread - at the moment my car seems to be running fine

 

[television]

You should bear in mind the O2 sensors once contaminated the fault does not go away, and that cars in this condition usually stop as the mixture is too week. If the engine has accepted the difference then the lamp will go out and not return. The MAF will and does turn the lamp on and if that can be cleared by a re start, then it is not the Co2 sensors.

Malcolm

 

[rosslyn]

engine light on

will MB charge me for them running a diagnostic on my car to check the fault

 

[OmniCognateNeutronRangler]

they shouldn't do. They didn't with me. But it's worth asking them first.

Have you had petrol from Tesco, Morrisons or Asda? If not then it's probably something else.

The trouble is that at the moment most garages are just going to assume it is fuel contimation.

 

[rosslyn]

yes i filled up with fuel from a Tesco garage that is on the list about 2 weeks ago

 

[OmniCognateNeutronRangler]

yes i filled up with fuel from a Tesco garage that is on the list about 2 weeks ago

well the good news is that Tesco are unlikely to argue about paying up. The bad news is that it does sound very much like the fuel contaimation problem. Get it checked out at an MB main dealer. The other, slightly bad news is that the parts are now very much in demand and will take a while to get hold of. Tesco will pay for a hire car though.

Go onto www.tesco.com\petrol and get a claim form. They told me today that they are planning on processing claims in 5 days but I'm not sure I believe that.

what is your car again?

 

[greenfingers]

So, is this another victim of siliconed fuel?

After reading about OCNR's woes, and the implied cost of replacing Lambda (O2) sensors, I am surprised not to see a 'sticky' on the subject.

Thankfully I haven't been near a Tesco fuel station recently, but there must be literally millions who have - probably wondering what they should be looking out for.

Personally, I would be concerned about engine longevity if my car had been running too lean while drinking a tankful of fuel.

 

[television]

Personally, I would be concerned about engine longevity if my car had been running too lean while drinking a tankful of fuel.

This cant really effect the long term life of the engine, there is nothing to harm it from the fuel side.

Malcolm

 

[Blobcat]

So, is this another victim of siliconed fuel?

After reading about OCNR's woes, and the implied cost of replacing Lambda (O2) sensors, I am surprised not to see a 'sticky' on the subject.

Omni has been posting so regularly on the subject it has stayed at the top of the section; http://forums.mercedesclub.org.uk/showthread.php?t=26014 and here http://forums.mercedesclub.org.uk/showthread.php?t=25715

 

[eric242340]

Omni has been posting so regularly on the subject it has stayed at the top of the section; http://forums.mercedesclub.org.uk/showthread.php?t=26014 and here http://forums.mercedesclub.org.uk/showthread.php?t=25715

And thus no need for a sticky