Lambda light
 

The lambda light in my 1997 V90 keeps coming on and I need to know why? My Volvo specialist garage do manage to turn it off but it then comes on again after 10 or so miles driving. Anyone had this problem and solved it?

It could be many many things, you need to get the codes read for a starting point.

1997 V90 probably has ISO9141 OBDII rather than the earlier proprietary protocol. If it says OBDII near the little cover next to the armrest you can almost certainly read the engine codes with a cheap OBDII scanner.

Mine periodically throws a P0422 Catalyst efficiency below threshold error. I carry a Foxwell scanner to reset the light which seems to come on every 150 miles or so. Eventually I shall get around to trying to fix the fault, but I suspect it might be due to a non-OEM replacement cat.

In my case, resetting by pulling fuse 1 in the under-bonnet fuse box seems to deliver a slightly longer lasting fix presumably because it resets the computer rather than just clearing the latest error.

You need to get the codes read properly Derek, find out what is causing the light to come on but from the sound of things, it's probably (but not guaranteeed) to be the Lambda sensor.

You could buy one and fit it yourself but you'd need the correct one for your car and after fitting, pull fuse #1 to reset the ECU fault code memory.

I'd hazard a guess fuel economy has dropped significantly since it started happening as well? :thinking:

Lambda light
 

Dave, Please remind me which is fuse number 1? Is it the top one behind the panel to the right of the dash board? I see there is a plastic clip to help pulling the fuse, but need to be sure it is not any of those under the bonnet. And do I pull out the fuse with the engine running or not? Sorry so many questions, but you seem to know what is what! Derek

Forrest, Which fuse under bonnet did you pull and was it whilst the ignition was on or when the engine was running? Thanks, Derek

Yeah, the one to the right of the dash. There should be a list of the fuses and relays on the cover.

Don't pull fuses whilst the engine is running or even when the key is in position II!

https://i.ytimg.com/vi/osvbqjX3L7g/maxresdefault.jpg

Sorry Derek, i had a brain-fog moment when i typed that, completely forgetting you had a 960 - the advice is good for a 940 but i'd need to double-check it also applies to the 960 which has, as you allude to, a different fusebox.

The keys should be out of the ignition, preferably away from the car as sometimes on refitting a spike can occur which triggers the central locking - not good to find yourself locked out of the car!

The resource i used with the circuit diagrams etc seems to have disappeared from the net so i need to search another one out, it might still be #1 fuse but as i can't be certain at this point in time, i'd rather say hang fire and i'll check for you.

The other method is to disconnect the battery for a while but that means having to enter the radio code etc which can be a bit of a pain.

Lambda Light
 

Dave, my car is a V90 1997. In case it means different advice!!
Derek

Thanks Derek, as far as i know the V90 is simply a rebadge of the 960 of the same era so should be ok, i seem to recall the diagrams for that year covered 960 and S/V90 models