Lambda Light!

[jeff.warner]

Hi.
Arriving at our destination today, manouvering in the car park I noticed the Lambda light come on, now, there seems to be a bit of a saga with this, in August 08 I had to have a new 'cat' and new Volvo lambda sensors fitted, in July 09 the cat was replaced under warranty, it failed its MOT on immissions,and now as I say the dashboard Lambda warning light is on once more, so while we were in the vicinity I went to Bridgend Volvo Specialists, and the car is booked in for this Friday, they did say that it was alright to drive it in the meantime - it does'nt seem to be any different driving it, although I don't know if its my imagination or whatever,but it does seem to be a bit louder.It seems to me that something must be causing this to reoccur.

[Merc85]

Hi i've worked in the Aftermarket Part world for over 15years now, Why did the original Cat fail in the 1st place? emissions? well why were the emissions high Catalytic Convertors don't just fail but 1 of the quickest way's they do are down to Over fueling this could be coursed by a number of things the fuel gets into the cat making it overheat this causes the Molith inside to fracture and break down thas not helping the already high emssion's then it's slowly breaks up and can clogg the rest of the system.

I think the 1st cat failed because of the Over fueling thats why the garage fitted the Lambda sensor's thinking that was them when is was NOT
then the second cat failed because the 1st problem was not diagnosed properly. and you will continue to get a similar result until such it is rectafied.

This is only based on my Opinon, and experience ONLY, I had the Lambda light come on on my 850 T5, this caused it to run a little richer, i quickly sort to rectify this, And after many things ie ECT and speed sensor's etc it turned out to be a blocked PCV system, as soon as i replaced the PCV the light went out and i regaind a slightly better MPG. Good luck

[Matthews 855 T5]

Like the good post above so many things can set off the Lambda light. Mine light up with a vacuum leak code which I was able to repair by changing the vac hoses and connectors.

When you say its running louder does it sound like the exhaust is leaking? Can you hear more growl from the middle of the car? The fact that you say its louder does imply that something is leaking but it may not be the exhaust.

Hope they sort it on Friday
Matt

[rippedoffagain]

Ignition problems can cause both the lambda light to come on, and premature failure of the cat.

I've been having bother with my 940. I'm not 100% convinced it is now fixed (the problem was intermittent) but just about everything involved in ignition was rotten. My car looked like it had been neglected by previous owner(s) so you may not need to worry about half of this if you know stuff has been done recently, but here's what I've found:

* Spark plugs were past it - now replaced
* HT leads were badly coroded - all now replaced
* Dirty contacts on the ignition coil - now cleaned up
* Dizzy cap and rotor arm had no recogniseable copper in them, just cracked black, crumbly stuff - now replaced.

The dizzy cap and rotor arm were the last bits to get changed, everything before that made an improvement but still didn't fix the problem, but seeing the condition of the old dizzy and rotor arm it was a miracle the car even started.

A dodgy MAF sensor can also lead to an incorrect fuel mix if the MAF is working but mis-reporting.

Of course, as others have said, many different things can upset the lambda sensor. In effect it is telling you that your fuel/air mix is wrong OR is not being burned properly, so anything that gives a bad mix or a weak spark will upset it.

[jeff.warner]

Thanks all,I'm eager to find out in the morning!

[jeff.warner]

Hi.
The trip to my local Volvo Specialist came up with the fault was probably my own , because we live in a very rural area and I tried to negotiate snow that was to deep caused a relay that is apparently behind the front bumper area to trigger an air pump on the engine to malfunction setting the light on ,on the dash. I don't know if that makes any sense to anyone,however, codes were erased, light reset and now things are back to normal again, if this fault should re-occur then it could mean a new air pump, so of course I hope it does'nt.
All the best.