How to Diagnose a Bad ECM/ECU on a 2001 XC70

2001 Xc70

MVS Volvo Forums member jcb went to great lengths to isolate the ECU in his 2001 XC70. He did work to make sure it was the culprit. This forum topic is how he diagnosed a failing ECM/ECU on his P2 Volvo. After two days of troubleshooting, I’m ready to send my ECM out for repair (2001 […]

ECM Airflow Motor is Important

MVS Contributor oragex made a video speaking about the importance of the ECU/ECM airflow motor. ECM airflow motor is important for keeping your car’s computer cooled down as it draws air from the cabin compartment. These little motors go bad limiting the airflow but can easily be replaced! Caution

Which ELM 327 To Buy?

So you want to use a phone or tablet to access your Volvo’s codes, reset procedures, and all the goodies you’re locked out of without an expensive scan tool. Since the age of dedicated scan devices is over, you can now use devices you have, like smartphones and tablets. But you need a bridge, something […]

Bluetooth OBDII Connect To ECU

MVS Forums contributor ESL explains how to connect to your Volvo’s ECU via Bluetooth adaptors: Torque uses the standard OBDII emission diagnostics. If you can’t connect with Torque, the first thing I’d try to do with Torque is find a way to force it to use the ISO 9141-2 protocol. If you can somehow monitor […]

Do our cars get used to one brand of fuel?

MVS Forums Member huzzsaba: Recently on a road trip, I filled up like I usually do at Canadian tire and got decent gas mileage that I usually get which is around 22 mpg. On the way back, I had to fill up at shell because there was no Canadian tire around, and I got the […]

Volvo 850 Repairs & Fixes

Here is a legacy list of various 850 repairs I’m moving to the VRD, for posterity. Replacement of entire sunroof system Member, atikovi was having trouble with the sunroof not working properly and decided to go to a junk yard and retrieve an entire unit- frame, motor, cables, etc. He then documented (with pictures) how […]

SAS Delete Theory


For those of you who also own Volvo, you would be familiar with “SAS Delete”. Remember that virtually all European cars (Volvo, VW, Audi, BMW, Mercedes, Porsche etc.) use the same setup for SAS, i.e., same Pierburg air pump, same air valve, similar ECU monitoring system.

Opinions on Manual Boost Control

In response to a request for opinions on how to safely boost a V70, MVS user pkplok posted this link which is specifically about boosting Volkswagens but should work for Volvos as well. Additionally, user SweedSpeed posted the diagram below which shows how to allow the ECU/solenoid to regulate boost in lower gears while utilizing […]

“628” R ECUs and 850s

So, I recently installed a 628 ECU and it works great. It feels like I have a little more boost everywhere, not just for 7 seconds, 30 seconds, or whatever the literature claims. This is in a MY94 850.

Tunes: Does One Size Fit All?

Fast Friday Volvo Performance and Tuning

Not all tuners adjust the ECU calibrations the same, that likely doesn’t surprise you. However what might surprise you is how it’s actually done. Here at ARD we tune each ECU by hand according to the customers environment, vehicle mods and particular driving style. Each file is read out from the ECU then decoded and put into our editor. We then edit the necessary maps, save the file, and load it back to the ECU. By tuning ECU’s this way we can make sure that all the relevant maps and values are edited for optimal performance and efficiency.

Fuel Cutoff w/ Stock ECU + MBC

Click through for a video example of the Volvo ECU cutting fuel after the parameters go off the map. Now that ambient air temperatures are very low, 9°F (-12°C), the air-fuel mixture is so dense that it’s going off the ECU’s map, and my Volvo’s computer is shutting down the party. It happens at low speeds […]