2000 S80 T6
Car stalled and set the immediate engine service required message. Used a conventional engine scanner which showed a single engine code for a bad turbo control valve. Hooked up the BSR-PPC scanner which read the proprietary Volvo codes which showed 20-30 error codes relating to the engine control module and a few other codes including a problem communicating with the ECM.

Cleared all codes and ran fine for rest of day.

Car stalled again the next day resulting in the engine service required message. This time it did not set an engine code but did set some of the proprietary Volvo codes. Cleared all codes but still did not start. Checked codes again and only a couple came back which included no communication with the engine control module (ECM). Also stated the voltage at the ECM relay was wrong. This is the relay labeled FMA10 in the engine compartment relay box.

Pulled out the relay and found one of the larger terminals had over heated which melted the plastic allowing the terminal to be pushed out of position inside the box. Bent the terminal so it gripped the contact securely and glued it back in place. Has been fine for a couple of days now.

Hope this helps someone someday. The BSR scanner certainly paid for itself by finding this problem. Unfortunately looks like they stopped making it.

http://www.ppc-diagnostic.com/info/

 

I have a stalling problem with my s80 t6. Wouldnt start the other day, but was turning over. I gave the bat a full charge and it starts and runs now. There was a code on it for the turbo control valve, but now its not on. The car still stalls every once in a while. I checked that relay that you were talking about and they all look fine. Any other ideas?

 

Try lifting the ECM relay slightly when the engine is running and see if it causes it to stall.
If you have not already done this, pull the relay and the one next to it. Pull out the gray plastic piece which is over the terminals the relay plugs into. You may need a small pair of needle nosed pliers to grab this with. It snaps into place.
Closely inspect the terminals the ECM relay plugs into for signs of being burned (dark color), spread to far apart or pushed out of place. The terminals should be clean and in same shape to the ones for the relay next to the ECM relay. If you have to fix the terminal, disconnect the battery first.
If still no luck, suggest you find someone who has a tool to read the Volvo proprietary codes. This is what led me to the solution. The standard engine code readers are not much help.
It is possible a battery not charging would set this code as well. You need to find out why it is not charging or why charging is intermittent. Put a meter on the positive terminal in the engine compartment with the engine running, turn all your accessories and lights on and you should have at least 13.5 volts.
If you have problems with a weak battery, suggest you go to Wal-Mart. The battery they sell for $70 is made for a Volvo a year or two older than ours and is identical to the one used in the car except it is about ¾” shorter which means you need to put a ¾” piece of wood between the battery and the plastic cover. I bought the larger size which is about 14” in length and has about 1000 amp capacity. It fit the battery hold down fine.