Lambda light again

[RaelG]

When I bought my car (96 850 10v) the lambda light was on so I paid for a new one to be fitted and this fixed the problem.

Stupidly I let the battery go too low so when I went to start it yesterday it just dribbled a bit and didn’t start. Charged it up and now it’s fine but the bloomin lambda light is on!

Is it likely the sensor has gone again?! MOT next Friday so timing couldn’t be worse! Should I try driving it a bit and see if it sorts itself out? Unfortunately plugging in a code reader won’t work because for some unknown and unfathomable reason it won’t work on my car.

[RaelG]

Quick
Update…the lambda light is gone. That’s the good news. The bad news is it’s now very unhappy indeed. I disconnected the battery and when I went to start it, it really didn’t want ti play ball. Finally it did but the idle every now and again drops to almost stalling then figured itself out and if I press hard on the gas the car shakes and it almost stalls and sounds like it’s not running on all cylinders. If I press gently on the gas though it’s fine and reacts and sounds normal. What have I done???!!!

[RaelG]

Another update…

Stand down helpers! It seems (I really hope it has!) to have fixed itself after a good sleep overnight. Started first turn of the key like it aways does and settled immediately to a nice idle, again as it always does. No more wobbling or hesitancy and accelerates as it should. So I’ve no idea what it was but fingers and toes and all things possibly that can be crossed, crossed, it’ll be ok!

[DaveNP]

Glad it has sorted itself and fingers crossed for the MOT, get that sorted and you've time to breathe.
If memory serves me correctly the lambda light on the dash (upsidedown Y on an orange background) is a general engine management warning not just the lambda sensor. the only way to know what it is referring to is to read the warning codes, if you've got an 'OBDII' port I believe it isn't actually properly OBDII (which is why a standard code reader won't read it) and the way to read the code is with a home made 'Blink Code Reader' similar to the previous generation's little boxes under the bonnet, try searching the 850/V70 forum using the words 'Blink Code' and it will bring up a page of threads about it.
In the past I found I was getting a lambda light because the sensor on the camshaft was developing a fault, it would trigger the light but then run OK for a while, but you can only know which sensor may be playing up by checking the codes.

[Simmy]

your car is likely obd1 . vol fcr should read it or make a blink code reader .

[RaelG]

Thanks guys. Mines of the age it needs the homemade code reader but for some reason it refuses to communicate. I can’t read codes and nobody seems to be able to kill the service light either, it’s like the ECU had turned its phone off and isn’t communicating.

Going to take it out again tomorrow for a little test run and see how it behaves. Like you say, get through the MOT then I can breathe easy!

[ASt85]

Originally Posted by RaelG

Thanks guys. Mines of the age it needs the homemade code reader but for some reason it refuses to communicate. I can’t read codes and nobody seems to be able to kill the service light either, it’s like the ECU had turned its phone off and isn’t communicating.

Going to take it out again tomorrow for a little test run and see how it behaves. Like you say, get through the MOT then I can breathe easy!

Resetting service light go here https://www.volvoclub.org.uk/reset.shtml

To cold reset other codes:
disconnect the battery, then momentarily "cross connect" the +ve and -ve cables whilst they are disconnected from the battery; this resets any codes other than the air bags as it dumps the code memory returning the car to learning mode.

Turn the headlight switch to dipped beam, turn the ignition key to position II then reconnect the battery, which prevents a voltage spike firing the air bags. It takes a varied stop/start up to 60mph over a few miles for the ecu to "re-learn" the normal driving parameters.

[RaelG]

If I’m feeling brave I might try that to see if the light goes out, thanks for the info.

To put this subject to bed, MOT passed today yay! No issues with the warning light and in fact no issues with anything, no advisories at all. An oil service carried out so all is well. Woohoo!