Greg,

Sorry this got so long. If you want to skip the drama let me just say try removing the ECM and re-seating it.

Now for the long version if you have time to read it...........

We went through this EXACT scenario with my wife's 05 S80 2.5T. She and my son were 850 miles away and heading home the first time it occurred so I suggested to her, over the phone, to limp it into a good Volvo indy that I know in that area. They cleaned the throttle body, which it was time for, cleared the codes, and sent her on her way. The guy that runs the shop said that in all the Volvos they've ever worked on, he had NEVER seen that version of Bosch throttle body ever go bad - they just need periodic cleaning. I should have digested that comment I bit more thoroughly......

Anyway, about 200 miles down I20, it happened again. She was freaked. No where to pull over on the interstate. She found that if she did pull over, shut off the ignition and restart it, it would be fine for a while. Anyway, they finally made it home.

So I once again removed the throttle body, witnessed the perfect cleaning they had done on the throat and plate, but this time I opened up the black plastic cover and carefully cleaned the contacts with alcohol. I got a bit of carbon-ish residue off of the contacts, but not enough to say it was the point of failure. Sure enough, I replaced the throttle body and after driving it about 20 miles on a good warm day it gave me "Reduced Engine Performance" and went into limp. Turning the engine off and restarting it cleared the message and restored full power. (Heat seemed to exacerbate the problem.)

So I called my buddy back at the shop that cleaned it the first time and he said "That's really weird", and AGAIN said he had never seen a need to replace the Bosch throttle body. You'd think I would have started to get it, eh? So he said to me "Well, maybe this is the rare one. Go ahead and try a new throttle body.

About two weeks later, with a brand new $350 throttle body in place, we headed off for the same 850 mile trip in the opposite direction. About 60 miles out...... "Reduced Engine Performance". (limping again).

Another call back to my indy shop for guidance and this time he says I need to start searching upstream for a bad connection. His suggestion was to remove the ECM and reseat it so as to refresh the connections. He also said to check over the harness between the TCM and the ECM for any possible weakness. I don't have the special tool required to unlatch the ECM and my attempts to do it with a long skinny screwdriver weren't working. So I took the car to a local indy close to my house and they did it. BINGO!!! Apparently that was the problem, as it has been running fine now for about 6 or 7 months. I'm convinced I have a perfectly good used TCM sitting on the shelf now. But if my indy mechanic is right, I'll never need it.