940 lambda light re-setting code??

[Britland]

Originally Posted by gpl1968

A simple way I found to reset the Lambda light is to :-

Turn on the ignition so the dashboard lights illuminate, but don't start the engine.
Gain access to the fuse board and remove fuse No.1
Turn off the ignition and replace fuse.
When you start the engine the engine, the Lambda light should stay out (provided the fault has been cured).

This method has the benefit of saving the radio settings.

Regards,

Gavin

I'm new to Volvo's and have this same issue in my 91 940 GL B200F, is it the fuse box in front of the gearstick? my Lambda broke out of the cat, so had it repaired and put back in but i was unsure how to turn the light of as its running really rough.

[Laird Scooby]

Originally Posted by Britland

I'm new to Volvo's and have this same issue in my 91 940 GL B200F, is it the fuse box in front of the gearstick? my Lambda broke out of the cat, so had it repaired and put back in but i was unsure how to turn the light of as its running really rough.

No, don't use that method. The engine should never be run without the ECU memory fuse installed as it can damage the ECU.

With the keys safely in your pocket but preferably out of the vehicle, remove fuse #1 for a minimum of 30 seconds and replace it. Then you can use the car normally and the light should stay off. If not, read the fault codes.

Note that even without the fuse installed the car can be started but the fault warning light aka Engine Management Light depicted as the Lambda Greek letter will NOT illuminate with #1 fuse removed.

Yes, that is the only fusebox on these models - am i right in thinking you had a new Lambda sensor fitted or just had the old one bodged back in?

[baggy798]

Wow, 15 year old thread. The dark ages.

Disconnect battery negative for a minute.

Alternatively read and clear the codes using the diagnostic socket on the NS strut.

[Britland]

Thanks for that Dave.

I've had it bodged back in for the minute and ordering a new one this week, I imagine that the Lambda is totally shot but its worth a try for now.

Cheers Liam.

[Laird Scooby]

Originally Posted by Britland

Thanks for that Dave.

I've had it bodged back in for the minute and ordering a new one this week, I imagine that the Lambda is totally shot but its worth a try for now.

Cheers Liam.

There's a fair chance it bounced around here and there while it was dangling on the wiring so yes, it will be pretty much dead by now as they're pretty fragile animals. They can take a lot of heat but not much in the way of knocks.

If the EML comes on more or less straight away, chances are the heater in the Lambda has broken, it may put the light out if you switch off and restart once it's hot. However there's also a high chance the actual sensor is damaged so will still bring the light on although not as quickly.

Let us know how it goes!

[Britland]

So... got home from work this evening, got straight in the volvo, took the fuse out and waited alittle over 30 seconds, put the fuse back in and turn it on. Boooom no light on and puring like a kitten! Dave you sir are a Saint!

Still having issues at it gets upto temp though dips power for a short period then comes back on.

[Laird Scooby]

Originally Posted by Britland

So... got home from work this evening, got straight in the volvo, took the fuse out and waited alittle over 30 seconds, put the fuse back in and turn it on. Boooom no light on and puring like a kitten! Dave you sir are a Saint!

Still having issues at it gets upto temp though dips power for a short period then comes back on.

YOu're welcome Liam, glad it seems to be sorted, for now at least. From the sound of your power dips, i'd suggest first of all a new thermostat, my 760 will do similar when the 'sytat is getting towards my 4 year renewal point. The fuel map is created for "ideal conditions" where the 'stat (among other things) functions like new and when it gets a bit older and weaker, the car takes that little bit longer to warm up. Instead of it perhaps giving a momentary dip in power during warm-up, you start to notice it.

That said if you can live with it, with the warmer weather coming in it should warm up quicker anyway but i would definitely suggest renewing the 'stat before next winter.

[Forrest]

Assuming pre-1994 cars are similar to later ones you lose remarkably little coolant replacing the thermostat without draining the system provided you park facing downhill. Conversely, you will lose a lot of coolant if you park facing uphill. You need the thermostat housing above the radiator.

Be careful undoing the M6 nuts. They are soft and easily rounded if they have been previously over tightened or are rusted. Use penetrating oil and a good quality 10mm socket.

Personally, I would usually combine changing the thermostat with flushing the system and new coolant. However, if you’re chasing problems this might help.

Be sure to have the right temperature ‘stat and the correct rubber gasket handy.

[Laird Scooby]

Originally Posted by Forrest

Assuming pre-1994 cars are similar to later ones you lose remarkably little coolant replacing the thermostat without draining the system provided you park facing downhill. Conversely, you will lose a lot of coolant if you park facing uphill. You need the thermostat housing above the radiator.

Be careful undoing the M6 nuts. They are soft and easily rounded if they have been previously over tightened or are rusted. Use penetrating oil and a good quality 10mm socket.

Personally, I would usually combine changing the thermostat with flushing the system and new coolant. However, if you’re chasing problems this might help.

Be sure to have the right temperature ‘stat and the correct rubber gasket handy.

All good advice and the coolant should be ethylene glycol (the blue or green stuff) and definitely NOT the red OAT type which will cause major problems for myriad reasons.

I think the OP is chasing a minor hiccup during warm-up, hence the advice about saimply renewing the 'stat - i'm sure you've read some of my posts where i explain my method of back-flushing etc which has always worked perfectly for me and those i've described it to except for one - they later admitted they'd skipped a step because they forgot and wondered why they had problems.

[Ian21401]

I concur with Forrest re the stat. housing nuts. IIRC they are flange nuts. If they appear corroded dose with releasing fluid a few days before attempting the job, clean the threads of the studs and treat them gently.
Re the coolant. When I renewed my stat. last year I syphoned off coolant by feeding a plastic pipe through the coolant reservoir, down the pipe to the radiator and into the radiator. Collected coolant in a plastic contained. Changed stat. without any coolant loss then replaced the syphoned off coolant. Job done.
I’ll try to look up how much coolant I syphoned off.

Edit:
I syphoned off 2 litres of coolant.
The stat. kit was obtained from my main dealer. £17.80. Part no. VO0273307.

https://www.volvoforums.org.uk/showthread.php?t=301913