The US-spec 850s never had an immobilizer as far as I know.
As far as the map differences, I have no idea, as I don't have the -926 bin available to compare. I would imagine any of the 98MY M4.4 2.5L LPT ECUs will work. IIRC, the -460 and -459 are US-spec LPT MY98 ECUs. The 97MY -936 ECU would also probably work.|
100% P&P, I can't say, but a good chance at a yes on that. The only difference I can see might be EGR and whether donor car for the engine originally has the SAS system. Both you can defeat in the ECU with hardware mods.
VS M4.4 tuning dead? Start again here?
- Chuck W
- Posts: 1310
- Joined: 24 December 2014
- Year and Model: 97 854 T5
- Location: Indianapolis, IN
- Has thanked: 96 times
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Re: VS M4.4 tuning dead? Start again here?
'97 854 T5 - Manual Swap/M4.4/COP/NA cams/P2R Brakes/16T/ chassis bracing/ XC70 nose swap
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
-
LaSof
- Posts: 3
- Joined: 19 May 2025
- Year and Model: 1988 Volvo 740
- Location: France
- Has thanked: 1 time
Gonna put that theory to the test I guess. I managed to find a -936 ECU, so I'll try to plug that, see if it makes any difference. Might as well since my ECU (-926) is a pain in the backside to get an immo off for. I should get it in 2 weeks time, I'll report back here for all the Euro peeps. Here's hoping 
-LaSof
-LaSof
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gwcook
- Posts: 8
- Joined: 18 August 2024
- Year and Model: 1998 V70 R
- Location: Chicago
- Has thanked: 1 time
- Been thanked: 1 time
Hey all,
Installed a wideband O2 sensor and put the 608_rev5b tune on the ECU, and besides max boost level, it seems to be driving perfectly and within the proper stoichiometric range which is awesome. Actually a little better from stops, as the car used to run lean when starting to move with the auto tune (~16), and now seems a bit rich (~13), which I assume is a sort of stall prevention mapping on the manual tune. Unfortunately, now I'm getting a DTC for the barometric pressure sensor - with the old (original) ECU installed, it reads perfectly within range (somewhere around 0.7v, I believe the proper range is 0.5v-4.5v). I thought maybe I had messed up when disabling the SAS pump diagnostics in TunerPro, but even without those modifications, the highest reading with the "tuned" ECU I am getting is 0.001v. Tested multiple times, and the sensor is receiving 5v on the proper pins from both ECUs, so the issue definitely has something to do with the way the new ECU is communicating with the sensor. The specific code I'm getting is EFI-422; any ideas of what's causing this odd value from the sensor? I'd really prefer to avoid disabling the sensor altogether as my drive down to college involves going through the Appalachians.
Edit: The ECU I have been tuning is from a N/A car (-743), and perusing this thread it seems like that may be the issue? I went for the cheapest one I could find on the m4.4 list on the m4.4 wiki which I had assumed meant it would work. Can anyone confirm or deny this is the probable cause before I drop ~$100 on an ECU from a turbo car (seems like that's the going rate for a turbo one).
Thanks,
Garrett
Installed a wideband O2 sensor and put the 608_rev5b tune on the ECU, and besides max boost level, it seems to be driving perfectly and within the proper stoichiometric range which is awesome. Actually a little better from stops, as the car used to run lean when starting to move with the auto tune (~16), and now seems a bit rich (~13), which I assume is a sort of stall prevention mapping on the manual tune. Unfortunately, now I'm getting a DTC for the barometric pressure sensor - with the old (original) ECU installed, it reads perfectly within range (somewhere around 0.7v, I believe the proper range is 0.5v-4.5v). I thought maybe I had messed up when disabling the SAS pump diagnostics in TunerPro, but even without those modifications, the highest reading with the "tuned" ECU I am getting is 0.001v. Tested multiple times, and the sensor is receiving 5v on the proper pins from both ECUs, so the issue definitely has something to do with the way the new ECU is communicating with the sensor. The specific code I'm getting is EFI-422; any ideas of what's causing this odd value from the sensor? I'd really prefer to avoid disabling the sensor altogether as my drive down to college involves going through the Appalachians.
Edit: The ECU I have been tuning is from a N/A car (-743), and perusing this thread it seems like that may be the issue? I went for the cheapest one I could find on the m4.4 list on the m4.4 wiki which I had assumed meant it would work. Can anyone confirm or deny this is the probable cause before I drop ~$100 on an ECU from a turbo car (seems like that's the going rate for a turbo one).
Thanks,
Garrett
1998 V70 R (with an m66 from an '05 S40 T5 AWD)

1983 BMW 633 CSi track car

1983 BMW 633 CSi track car
- Chuck W
- Posts: 1310
- Joined: 24 December 2014
- Year and Model: 97 854 T5
- Location: Indianapolis, IN
- Has thanked: 96 times
- Been thanked: 333 times
Pretty sure the NA M4.4 ECUs don't have any of the components populated on the board for the boost control. What are you doing for your boost control?
Whether this is also the source of your -422 code, but it is highly likely.
There is coverage of that code HERE on this site.
I would source a turbo ECU, regardless.
Whether this is also the source of your -422 code, but it is highly likely.
There is coverage of that code HERE on this site.
I would source a turbo ECU, regardless.
'97 854 T5 - Manual Swap/M4.4/COP/NA cams/P2R Brakes/16T/ chassis bracing/ XC70 nose swap
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
-
gwcook
- Posts: 8
- Joined: 18 August 2024
- Year and Model: 1998 V70 R
- Location: Chicago
- Has thanked: 1 time
- Been thanked: 1 time
Thanks for the response, Chuck!Chuck W wrote: ↑07 Jul 2025, 07:42 Pretty sure the NA M4.4 ECUs don't have any of the components populated on the board for the boost control. What are you doing for your boost control?
Whether this is also the source of your -422 code, but it is highly likely.
There is coverage of that code HERE on this site.
I would source a turbo ECU, regardless.
For some reason, I assumed that any M4.4 ECU would work, so made no changes to any boost control hardware. I'm assuming if the ECU didn't have any boost control, that the rest of the boost control hardware on the car defaulted to a "limp home" setting, so allowed me to get around 3psi at WOT with some fun wastegate noises. Only took the car for a spin around the block so hopefully didn't do any damage to those components.
Was able to score a '98 R ECU on ebay for $50 so will now be using that as my base ECU for flashing, so I can still keep the original untuned ECU just in case. I'll post an update here if that fixes the issue.
Best,
Garrett
1998 V70 R (with an m66 from an '05 S40 T5 AWD)

1983 BMW 633 CSi track car

1983 BMW 633 CSi track car
- Chuck W
- Posts: 1310
- Joined: 24 December 2014
- Year and Model: 97 854 T5
- Location: Indianapolis, IN
- Has thanked: 96 times
- Been thanked: 333 times
I've got a Spartan 2 on my '97 T5. I don't run an AFR gauge.
The general installation/mods to install a WBO2 are on the M4.4 Wiki.
I'm running one of VAST's WB Modulation bins on my car, but you can also just set things up to do general logging for tuning. That part is built into the .xdf for the 607/608 bins.
The general installation/mods to install a WBO2 are on the M4.4 Wiki.
I'm running one of VAST's WB Modulation bins on my car, but you can also just set things up to do general logging for tuning. That part is built into the .xdf for the 607/608 bins.
'97 854 T5 - Manual Swap/M4.4/COP/NA cams/P2R Brakes/16T/ chassis bracing/ XC70 nose swap
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
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Turboforslund
- Posts: 2
- Joined: 26 October 2025
- Year and Model: SC Volvo 850 T5 -95
- Location: Sweden
- Been thanked: 1 time
Hi guys!
Nice to see you starting something new, fresh and promising here. I really like the optimism and i'm happy to help out if needed!
// Turboforslund
Nice to see you starting something new, fresh and promising here. I really like the optimism and i'm happy to help out if needed!
// Turboforslund
- Chuck W
- Posts: 1310
- Joined: 24 December 2014
- Year and Model: 97 854 T5
- Location: Indianapolis, IN
- Has thanked: 96 times
- Been thanked: 333 times
Glad to see you here. Your info and experience will be very valuable!Turboforslund wrote: ↑26 Oct 2025, 14:48 Hi guys!
Nice to see you starting something new, fresh and promising here. I really like the optimism and i'm happy to help out if needed!
// Turboforslund
'97 854 T5 - Manual Swap/M4.4/COP/NA cams/P2R Brakes/16T/ chassis bracing/ XC70 nose swap
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
'97 855 GLT - Hers. RN swap/16T/COP/VVT/exhaust/302s/Flashed M4.4/ chassis bracing/ 2 kid seats
'78 GLE - Waiting in the wings. Future whiteblock/T5 swap.
The Others- '83 TBird turbo, '85 Mercury Marquis LTS (1 of 134), '86 LTD Wagon, '81 Granada GL, '76 Beetle, '93 F-150 I6
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