940 SRS light
 

Hello all

My mates 940 needed a new rack so we fitted one, during fitting our other mate decided to be a pleb and jump in the car and spin the steering wheel over and over again like a child. We then started the car up after the change and the SRS light came on! Took the air bag squib off and it was knackered so I gave my spare one to my mate and he has fitted it. Pulling fuse number 1 for a over a minute does nothing and the light is still on.

Any ideas what could be up with it? We need to figure out how to read fault codes on it too.

It's a 1995 b230fk estate.

Diagnostic connector "B" under the bonnet is where you read the codes Luke, as for your mate that kept spinning the steering wheel, in future cable tie his hands behind his back before letting him near the car! :speechless-smiley-5

According to Volvo, any more than 3 turns in either direction will kill the rotary coupler/clock spring/contact reel/squib so it's a fair bet your mate murdered the original.

Are you sure the one you gave your mate that owns the car is ok? Could simply be it's held and recorded the fault from the first one that died so the replacement might be fine but you need to clear the fault first using the diagnostic connector.

I can't find any evidence that the SRS ECU has power from fuse #1, as it's (supposedly) a safety critical item it's possible it has its own internal memory in the SRS ECU that needs clearing - i know of a few other cars like that. Good call pulling fuse #1 to try and clear the memory though! :thumbs_up:

Could a 95 car have the OBD port in the armrest Dave ? My 96 does

Do you know what sort of connector is needed to read the codes Dave?

The one I gave him was from my breaker and I just checked in the video of it starting up, no SRS light on the dash. "New" one has resistance inside like a clock spring where as the old one spins freely.

Now that you have said about it not running through fuse 1 that would make sense, I will see if there is a separate fuse for it and pull that.

It might have Mark but the Volvo sources i was using suggest it's the underbonnet code reader, the 96 model had the armrest mounted not-quite-OBD connector.



https://www.volvoclub.org.uk/faq/ElectricalSRS.html

If it's the one i'm thinking of Luke, you won't need any connectors - have a look at the link there and follow the "1992+" code reading where it explqains about the connector box and the probe and LED under the bonnet near the suspension turrets.

The insides of the roatary coupler are basically a clock spring or 2 to transmit power on different contacts. They're fairly robust and durable until some muppet goes silly on the steering wheel or until they're fitted incorrectly. Ideally when removed, the front wheels should be in the straight ahead position and when removed, a piece of tape should be wrapped round the inner and outer halves to prevent them "unwinding".

If the suspect one spinds freely, it's TARFU.

I couldn't find a separate fuse for the SRS ECU memory, it has power from the ignition switch in positions 2 and 3 but seemingly no other permanent (memory) feed.
I think the only option is to read the codes and reset using the underbonnet box/probe combo.

Fingers crossed there's no damage done to the ECU.

Well we have had a look and can't find any led readout box thingy in the engine bay but there is a connector under a blank in the arm rest so I guess we need a code reader for it.

My mate pulled the under dash trim off to have a look under there for a connector and found the previous owners improvements of an alarm are up the same standard as the rest of the "improvements" and the wires have all been twisted and taped. Time to go through this car properly and remove all the b0ll0cks that has been added and remove all the suspect wiring.

Horn has also stopped working now.

Obviously a later car than i thought then!

I'm not 100% familiar with airbags on Volvos (thankfully never had one!) but i know on my Rover, the horn contacts go through the rotary coupler on the steering wheel which is fitted regardless of whether it has an IED or not. If your mates 940 is the same, it's possible that's why the horn has stoppd working.

Check the obvious first like whether the horns themselves are working, could be as simple as they've died or the fuse has popped.

Your horns are probably disintegrated Luke. They are under battery tray and not long after I got mine they stopped working. Cheap enough to replace and somewhere on here a link to the ones I bought. I think Bob purchased them as well

Unfortunately the SRS ISN'T readable from the "OBD" port; it only reports on Ignition, Fuel, ABS and Cruise Control. I'm not sure how you would go about getting its fault codes, unfortunately.

As in all things its proably in the Tech section on the main site, Clicky here

As for you mate tell him he isn't allowed to play with the adults anymore and to go play fortnite!