S/V/C70 1997 S70 Auto Trans will not engage most of the time

edited July 2020 in General

Hi guys, new to the forum and new to Volvos. I picked up a 97 S70 (2.5L 20V non Turbo) the other day for next to nothing as it has the issue I'm asking about. However it has been well looked after and serviced etc, and I would like a project to work on while things are quiet.

The issue is that it's not going into any gears (occasionally has engaged, then drives for 50-100m then disengages and the engine revs like its in neutral). I hooked it up to my OBD scanner and it had a P0500 - Vehicle Speed Sensor A error on the A/T computer. This was accompanied by the flashing up arrow, check engine light and the Sport, Eco and Winter mode lights flashing.)

I've tried the rapidly shifting through every position to clean the contacts on the PNP switch to no avail as well.

I cleared the code to see if that was causing anything and the warning lights have gone away and after a fair bit of testing the engine and a/t computers haven't thrown any further codes, however the issue is still persisting - just wont engage.

Occasionally there is a buzzing sound coming from the trans side of the engine, sounds like a relay or something, possibly a solenoid buzzing in and out, not 100% on the origin, but I have heard that the shift solenoids on these gearboxes can go quite regularly - however there is no code in the A/T computer about it.

The previous owner took it to a shop and they put new trans fluid in it, which didn't fix the issue for long enough for him to even get home, checked the fluid today and is nice and clean - not burnt and has a good level.

Having a look through the service history it had a second hand / recon trans put in it in 2018 unfortunately this hasn't lasted too long.

Any insight into the issue or advice on some further diagnostic / troubleshooting would be most appreciated. I'd like to try and do the work myself as well as I'm not planning to invest too much money into this more of just something to keep me occupied. I've done a fair bit of car work in the past so I've got a fair idea on working on cars. The engine on the car is in really good condition, full service history etc, just had timing belt and water pump done, really low Ks, hence not wanting to just give up on it.

Thanks for your advice and assistance in advance.

Lucas :)



  • I realise now this is in the Website category, didn't see the category selection box. Sorry about that, hopefully an admin can move this to the right category


  • I've got a spare known good box you can have for free if you come pick it up from 2148

  • Thanks @Philia_Bear I would love to take you up on that offer but I'm in SA and with everything going on at the moment that would be near impossible. Will probably try to find one at a wreckers if it comes to it.

  • Update - Tonight I tested the Soleniod resistences and all test okay as per the AUTO TRANS DIAGNOSIS - AW50-42LE recommendations. So if not the shift soleniods would anyone have any other suggestions as to what could be causing the issue. If not I'll probably flush the trans oil over the weekend and see if we can get any further with working out whats going on.

    Cheers, Lucas

  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.

    I had a failure of same box in v70T5, very noisy graunching noises and banging, i scrapped the car, for me not worth swapping in another gearbox , it may be for you if you do it yourself.

  • Hello again all. Had a bit more time to check out the car today. Tested the PNP Switch - all good. Also started doing a flush of the trans fluid - problem is the car will not stay in gear long enough to cycle the fluid around much at all - may need to wait to finish the flush process.

    I have noticed, that after sitting for a while when you start the engine back up there is a buzzing noise coming from in the transmission. Sounds like a pump or something to me, not too sure. Here's a clip of it. https://youtu.be/FzCjQ4N3ayo

    Funny thing is - It'll drive fine as long as its making that noise, as soon as it stops like in the video you lose all drive. Noise usually lasts 15-30 secs.

    Anyone heard this noise before or know what it could be?


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