Green light on dashboard ?

[mikeatvillage]

Hi, sorry if this is a faq... I forgot to look in my Haynes last night and can't find anything here by searching.

I had a green triangular light come on yesterday on the dashboard with a strange symbol. As it was green I carried on driving, got to destination, parked up for an hour then returned to the car and the light didn't come on again. Just wondering what it was and why ?

Thanks

[Oli]

Was there an orange background to the green triangle, and was the strange symbol like an upside down y? If yes, then that's the symbol for Lambda, or in Volvo speak, something to do with the fuel and emmissions systems. If it's not on now though, it's likely to have been a hicough, as if there's a real problem to fix, the light tends to stay on.

Oli

[ivor940]

Hi, Does the light come on with ignition and then go off with engine running? If no, the bulb could be gone. The Lambda light can come on when the engine stalls or has a low voltage event. If it does light with ign on only and stays out with engine running, it means the Fuel and Injection has no faults it can report on. Some faults do not cause lambda lamp to light, but odd running faults or fuel consumtion will advise you of them.

ivor940

[mikeatvillage]

Thanks guys,

No orange background, just a green triangle, and the symbol is Lambda (I Googled). It always lights up when I turn the ignition on and goes off as soon as I start the engine. It's not coming on again so maybe it was just some sort of glitch but I'll keep an eye on it.

Mike

[ebdl]

I presume that the 440, like the 850, has an ECU that allows you to download fault codes to find out why the lambda light came on. If you're not comfortable doing this yourself, most garages have fault-code readers these days. I don't think it's a difficult thing to do yourself if you want to - have a search through this forum for posts about reading fault codes.

In my experience, when they come on and go off again shortly afterwards, this is usually a fuel trim error (i.e. the mixture's been a bit off for some reason).

Other people will know more about this than I do.

Cheers, Ed

It sounds like it's working as it should. It will come on when you turn the key to position II (so you know it's working) but only if it stays on when the engine is running should you worry.

It highlights any problems in the fuel / exhaust system which cause emissions, basically.

[ahal]

Dear Mike,

I have the same problem with my 440. I could be setting myself up for an avalanche of contradictions, but here goes. On my car, a 1994 134,000 mile 1.8
440 xi ( which I've owned for 5 years ) this light comes on during long runs, especially if there's a strong ( against the front of car ) wind.

I do a 300 mile round trip once a week, and have been doing for 4 years in this car. Stopping off at a petrol station for a cup of coffee cures it: the 20 minutes or so break sorts it. This problem began about six months ago, and was a direct result of letting the car RUN OUT OF PETROL!!!

In my own case, I think the Catalytic converter - part of the exhaust system - is dead. Running the car completely out of juice can wreck this important ( and insanely expensive ) component. The catalytic converter is an encased ceramic honeycomb through which the exhaust fumes travel ... very delicate. It is supposed to 'trap' lead particles from the fumes before they leave the car. The Lambda sensor guages the pollutant level of exhaust fumes, and tells the engine what to do accordingly.

To the best of my knowledge ( and I'm not an expert, but I've asked a lot of q's and read up a lot on these things ) the lambda tells the engine to run leaner if the smoke coming out the exhaust is too thick, or to run less lean if the smoke is too 'thin'. The catalytic converter is supposed to have a purifying effect on the exhaust fumes, so if that is defective, the sensor light ( green thing which has an 'A' like symbol ) would stay on.

Don't be intimidated by terminology ... I remember feeling like an idiot asking people questions and being bombarded with stuff I didn't understand. It's really not rocket science at all. Basically the electronics tell the engine what to do, so if they go psycho, so does the engine.

The other member's suggestion about the fuel system sounds more accurate to your specific problem in ways, particularly the odd starting business, but I decided to add my bit as the symptoms are otherwise identical. Best of luck with your new car ( at 88k., it's only 'run in' in Volvo terms! )

Regards,

Anthony.

[ebdl]

Originally Posted by ahal

The catalytic converter is an encased ceramic honeycomb through which the exhaust fumes travel ... very delicate. It is supposed to 'trap' lead particles from the fumes before they leave the car.

There shouldn't be any lead in your petrol these days, especially if you're running a car with a catalytic converter that's set up to run on unleaded.

I still think your best course of action is to get the fault codes read somewhere as it should help to show where the problem is. Air leaks in the various vacuum pipes that connect to the fuel injector can bugger up the mixture - this is a common problem with 850s and easily and cheaply fixed. It results in the same symptom of the lambda light occasionally coming on while driving. In the short term I found that using decent quality petrol (Shell) helped.

Cheers, Ed

[ahal]

Hi again,

The other member is right about the lead, but let's not get hair - splitty, the Catalytic converter is there to take bad things out of the smoke. Petrol quality is unlikely to make much difference: these days that's a myth in my opinion, and experience. I had used about 25 different brands over 5 years without any problems whatsoever.

It may well be something in the DISTRIBUTION of the fuel as per an earlier suggestion.

Regards,

Anthony.

[mikeatvillage]

Thanks again,

no sign of the light coming on again :-) I don't spend much time under the bonnet (except to fill up with water all too frequently) but I'll take a look at all the hoses etc. to see if there's anything obvious and I'll look around for somewhere I can get these fault codes read. It was a particularly hot day and the car was a little short of coolant - maybe that messed things up.

ATB

Mike