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Help with ECM 1998 V70 manual wagon

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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abscate  
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Re: Help with ECM 1998 V70 manual wagon

Post by abscate »

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
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scot850  
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Post by scot850 »

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

Neil.
2006 V70 2.5T AWD Polestar tune
2000 V70 R - still being an endless PITA
2006 XC70 - Our son now has this and still parked in our garage
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L - Sold
1993 850 GLT -Sold
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1997 Volvo 850 SE NA - Went to niece in California - Sold
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abscate  
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Post by abscate »

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.
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1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 XC90-in-Red
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gregoryahunter1
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Year and Model: 1998 v70
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Post by gregoryahunter1 »

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

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misha
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Post by misha »

I'm pretty sure it won't.
P'n'p switch must be jumped after manual swap.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

gregoryahunter1
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Post by gregoryahunter1 »

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?

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V50M66
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Post by V50M66 »

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.
1998 V70 AWD - Emerald Green/Tan - M56/Delta link swap, VAST tuned, lots of fun
1998 V70 NA - Nautic Blue/Charcoal - Factory M56/slicktop track car
2006 XC70 Ocean Race - workhorse
2002 S40 1.9T - daily

2004 XC70 - Mystic Silver/Black - former workhorse, parted
2005 V50 T5 M66 FWD - Black Stone/Black leather - former garage queen, sold

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