Engine warning light

[yeti]

Engine warning light (Amber) came on this morning for the second time in 2 months and has stayed on. First time I took it to the dealer it went out when I was trying to demonstrate the problem and they got nothing when they queried the engine management Unit (or whatever it's called). Today’s incident appears to be more permanent. No engine misfire or any degradation in engine performance, false warning...??? or something else.

 

[Brian WH]

Engine warning light (Amber) came on this morning for the second time in 2 months and has stayed on. First time I took it to the dealer it went out when I was trying to demonstrate the problem and they got nothing when they queried the engine management Unit (or whatever it's called). Today’s incident appears to be more permanent. No engine misfire or any degradation in engine performance, false warning...??? or something else.

Who knows could be almost anything engine wise. Need another diagnostic to resolve, hopefully with the light still on. ECU should have shown a fault before as it keeps a log???

 

[Phil Holcroft]

Hi,

Just posted a long reply to this and seem to have lost it!
Long story short - this happend to me (Petrol 430) and it eventually turned out to be one of the catalytic converters in a down pipe.
The diagnostic box only seems to tell them the symptom not the cause - eg "misfire on cylinders 2-4" they then have to find out why!
If it is the cat I'd look for an OE one as they are less than half price and even if they only last 2 years it's worth it.

 

[yeti]

It's a diesel so I don't think it has a cat (or any other fury animal). The light has gone out now anyway, I was low on fuel at the time so suspect it could have been detecting low fuel pressure.

 

[Phil Holcroft]

You may well laugh!!! About 2 years ago some kind of rodent took up residence under the bonet of my wife's 320 estate, chewed the plastic tops on the suspension arms, brake master cylinder plus various bits of the wiring harness......could have done with a cat! Hope your problem doesn't come back!

 

[Brian WH]

It's a diesel so I don't think it has a cat (or any other fury animal). The light has gone out now anyway, I was low on fuel at the time so suspect it could have been detecting low fuel pressure.

Must have been very low to detect low fuel pressure mate, but who knows with these electronic gadgets.

 

[230K]

It's a diesel so I don't think it has a cat (or any other fury animal). The light has gone out now anyway, I was low on fuel at the time so suspect it could have been detecting low fuel pressure.

Your diesel does have a CAT. Do not know anything about the warning light though.

230K

 

[jimmy]

Yes all diesels have CATS now. I have a fault code reader that also re-sets the fault light, it tells you what caused the fault light to come on and you can also read live sensor data. It's very impressive, tried it on lots of cars except a MB, does anybody know if the newer 2001- MBs have the new industry standard 16pin OBD or OBDII diagnostics socket?

I would like to try it out if anybody has a problem?

 

[silverarrow]

can but a lead to connect to the round pin to 16

 

[DrNick]

Moving down market a bit, the same symptoms appeared on my Fiat Brava Diesel. Engine management light on every so often but no difference in performance. This was due to water collecting in the fuel filter. Changing the filter (and draining the water) solved the problem. Maybe its as mundane as this?

Nick