My daughter hit a deer with her 1995 940 sedan and the airbags and seat belt tensioners deployed. I am trying to get her 940 back on the road. She really likes the car. I have two 1994 940s for parts. I read out the SRS codes and got in order:
2-1-2 Steering wheel module, break in wiring
2-2-2 Passenger module, break in wiring
2-3-2 Seat belt tensioner left, break in wiring
2-4-2 Seat belt tensioner right, break in wiring
2-1-1 Steering wheel module, short circuit in wiring

I expected to see a 1-1-2 Internal fault in the sensor unit but did not. I am wondering if I need to replace the sensor unit? It would seem that the accelerometer would sense the collision and then return to the pre-collision setting but that may not be the case.

Thank you - Glen
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running

Oh, and one other thought, if there is an insurance claim involved, they may want to see a licensed tech sign off on both the removal from the donor car(s) and the installation before allowing you to put the car back on the road. From an insurer's point of you, a 940 of your vintage will more than likely have been declared a total write off when the SRS system deploys. That can make it even trickier to get it put back on the road as a full safety inspection may be required. Check with a friendly local body shop and/or your insurer and/or your motor vehicle department on the requirements in your jurisdiction and be prepared to find a tech willing to sign off on your work.

EDIT: I just spotted your original thread on this back in December. Somehow I missed it. You were cautioned about salvage status then. Did you look into it? You could well be wasting your time if you don't sort this out beforehand.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

I'll update the thread when I progress more on the job. It's still a little cold here in Minnesota to work on the car too much.
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running

I replaced the front Seat Belts and Airbags with not problems the last couple days. The biggest job, time consuming, is to remove and re-install all the plastic and the front seats to get to the parts.

I was most hesitant about the passenger airbag, which turned out to be easy, just time consuming. I removed the glove compartment which allowed me to get to two 10mm long nuts which held the airbag in place. There are also two hidden adjustment screws under the ledge just above the top of the glove compartment door to adjust the alignment of the airbag with the dash. I haven't had the windshield replaced yet but don't see a problem with a bent windshield frame.

The parts were from a 1994 sedan and the part numbers all matched with the parts from my 1995 sedan.

An important find for me was clearing the SRS codes which I copied from https://brickboard.com/FAQ/700-900/ElectricalSRS.htm
and repeat here:

To clear fault codes other than 1-1-2 (indicating a crash sensor fault, which must not be cleared but rather returned to the dealer):

Remember to read the codes three times before clearing.
Remove the selector lead from the side of "A" and insert it into terminal 5 of output box "B".
Turn the ignition "on" to key position II.
Press the button on box "A". Keep it pressed for at least 5 seconds.
Release the button. The LED lights.
Press the button again when the LED lights and keep it pressed for at least 5 seconds.
The codes are now cleared.
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running

I did the same operation on a 1994 940NA after a collision, replaced ALL SRS related components, and the system needed no reset to my great surprise and delight! The light went off by itself and everything functions as it should, light and code wise.

Dear jd620,

Hope you're well and glad to hear that you got everything back together in good order!!

Stay well!!

Yours faithfully,

Spook

Thanks for your help Spook. I failed to mention that I replaced the sensor and steering wheel also. Now to get the windshield replaced and get the replacement hood and trim around the headlights painted.
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running

Dear jd620,

Hope you're well. You're welcome!

Hope you can find a windshield easily!

Stay Well!

Yours faithfully,

Spook

Exactly what Spook said.

Based on my limited experience and the likelihood of minimal structural damage in a deer collision, you'll likely find the control module is okay and won't need to be replaced as long as you can do the reset, but it's nice to have access to a spare in case you need it. Do be careful when lifting/dropping the front seat. If you dent the control module case you won't pass inspection even if the codes do reset.

It seems from the code you may find the clockspring broken. Be extra careful when installing it to have the steering wheel and front wheels centred and count the clockspring turns so it's correctly set in the neutral position.

I've got a good tale here on that. The bozo garage tech that did one of ours installed it with the steering wheel turned 360 deg off centre and the clockspring broke after a few hard right turns in a parking lot. The same bozo also pinched the main harness in the door pillar behind the lower seat belt bolt and shorted out the wiring to the rear of the car. Couldn't find the problem after two returns to the shop. This was not a small shop, so I was very disappointed when I learned they'd put a junior apprentice on such a job. I blew my lid, took the car back, found the problem in 20 minutes and fixed it. Two weeks later the clockspring broke, so I didn't even bother going back, just fixed it myself and phoned them up to give the manager an earful of expletives. This was after we'd waited over 3 months for the shop to repair the car, always with an excuse about not being able to find a salvage part and the insurer not being willing to pay list for new parts (othewise they'd have to write it off). I found out later that what pushed the job to get finished was the insurer getting tired of paying for a loaner and the shop's lease on their nice little Minicopoper S loaner was up and I said I wouldn't be bringing it back until ours was ready.

Good luck. Just be extra careful. Safely bag the battery cable, always try to keep your head out of the firing line, especially when disconnecting/re-connecting wiring, and avoid any possibility of static discharge.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Dear jd620,

Hope you're well and stay so. Volvo Service Manual #32231/1 (Section 8 ⏤] SRS [Airbag]), p. 140, instructs:

"The sensor unit should always be replaced if:

Diagnostic Trouble Code (DTC) 1-1-2 has been stored or
The DTC cannot be cleared when the car has been repaired - there is still a fault in the sensor unit or
The sensor unit is mechanically damaged or
There is mechanical damage to the floor of the car in the area of the sensor unit, which could weaken the sensor unit mountings. Remove the sensor unit and check that its mountings are not cracked." This is a verbatim quotation.

These instructions suggest that you should replace all expended units: both airbags, both seat-belt tensioners, all wiring (fluorescent orange), the steering wheel, and the "clock-spring" connector to the in-steering wheel airbag. If, after doing all this you do not see DTC 1-1-2 code, all's well with the sensor module.

Note: the SRS cable to the in-dash passenger-side airbag is secured - behind the center air-vents - with a heavy-duty black plastic cable tie.

To cut the cable tie, I converted an old hacksaw blade into a "hook-knife". Using a hand-held electric grinder (e.g., a Dremel) and an emery cutting disc, I formed a hook at one end of the blade: I cut a slot from the toothed-edge of the blade to a blade mounting hole. I sharpened the hole's edges using the electric grinder and a small abrasive stone.

To cut the cable tie, I put the hook-knife behind the cable tie and tugged until it cut through the plastic. This wasn't easy, but saved me having to remove the air vents to get better access.

Hope this helps.

Yours faithfully,

Spook