Help with ECM 1998 V70 manual wagon

Post by **abscate** » 06 Jul 2025, 04:39

I think I have an old 1998 ECM in my stash upstate but it would be for an automatic car. I’m 99% it would start and run but would probably either CEL or TCm arrow flash if it can’t see the auto transmission

Post by **scot850** » 06 Jul 2025, 09:20

Would it even start without the PnP signal? They can be re-written as those who have done manual swaps have to do.

Neil.

Post by **abscate** » 06 Jul 2025, 09:58

scot850 wrote: 06 Jul 2025, 09:20 Would it even start without the PnP signal? They can be re-written as those who have done manual swaps have to do.

Neil.

I’m 99% sure it will start and run, but code.

gregoryahunter1 · Post by **gregoryahunter1** » 06 Jul 2025, 11:44

Follow up from me (OP) - I will go through all of the suggested items with my mechanic that DO NOT have to do with the ECM tomorrow, AND I ordered a new Type R ECM from VAST as well. If it does turn out to be the computer - I will have a new one by Tuesday. If it isn't the ECM (as many of you suspect) then I get an ECM with the Type R tune: WIN WIN! Thanks again for all of your help

Post by **misha** » 06 Jul 2025, 11:44

I'm pretty sure it won't.
P'n'p switch must be jumped after manual swap.

gregoryahunter1 · Post by **gregoryahunter1** » 16 Jul 2025, 11:43

UPDATE: My mechanic was able to get the car started with a combination of unplugging some incorrectly connected plugs and my new ECM from Vast Tuning. So its just about ready to be driven.

Since its been sitting for years - What do yall suggest for maintenance before I drive it much - I was thinking:
-Oil Change
-Coolant flush
-Manual transmission fluid change
- new brake fluid
-look at belts

Other stuff I should do?

V50M66 · Post by **V50M66** » 16 Jul 2025, 15:42

Good to hear it’s alive. You’ll really enjoy that spicier ECU once you start driving the car.

That’s a good start, keep going. Don’t just look at the belts, replace them, especially if there’s no history on them. Timing belt, water pump, idler, and tensioner should be a priority. Do the accessory belt and its tensioner as well. Spark plugs too - add coil, wires, and distributor cap/rotor if they haven’t been done recently. All the coolant hoses. Engine mounts. Suspension. Brakes. Etc

If you can’t tell when (if ever) something has last been replaced and it would leave you stranded/cause major issues if it failed, replace it.

Make sure to use only quality parts or you’ll be right back at it sooner rather than later. Use only trusted parts from FCPEuro or the Volvo dealer - no parts store/FleaBay/Scamazon/Uro/ ProParts crap.