'04 S80 2.5T - Performance Issues, Limp Home, ETM/CEM Replaced... What Next?
 

Here's the scoop: I have a 2004 S80 2.5T w/ approx 79,000 miles on it that I purchased back in February. About a month after I purchased the vehicle, I decided to swap in my Alpine Head Unit for the factory stereo so that I could have iPod capability. Shortly thereafter I began getting "Reduced Engine Performance" messages and the car would go into it's "Limp Home" mode. I finally took it in to the local volvo shop (non-dealer) so they could pull the codes and tell me what was going on. The codes were related to the ETM and so they replaced it to the tune of $830.98. Two days later I was back ast the shop with the same issue. They scanned the codes again and this time it was giving ETM codes and CEM (Central Electronics Module, or something of that nature) Codes. They replaced the ETM again (no charge) and the CEM to the tune of $826.39. At this point they also applied the software update to the car to remove the factory radio.

All was well for about a month, and then it all started happening again. So I took it back into the shop, he cleared the codes, road tested the car and it was working "fine" so he sends it home with me again. Car is still having the same issue. So I opted to remove my Alpine HU and put the factory stereo back in. I took it for a test drive and I had to fight to keep the engine from shutting itself down because it was idling so hard. I was able to make it back to the shop and I left it there for another 4 days. When it got it back after 4 days, they said that the issue didn't manifest itself while they had it, but that they did find throttlebody codes in the recent code history. They ran the software update to put the factory radio back into the "loop" and put a good 80 miles on the thing to test it out. Unfortunatly, 10 miles after I picked the car up, the issue was back. Same "Reduced Engine Performance and drop into it's lovely "limp home mode"

Things to note: The factory wiring for the radio was not changed in any way. A wiring harness was used in order to leave the car intact.

I am getting sick and tired of having a car that doesn't work. So I have some specific questions
1) Does anybody have any suggestions as to what the issue could be?
2) Do I need to abandon ship with this independant volvo shop (who hasn't charged me a cent since the initial $1600) and go to the dealer, or should I stay with this shop and have them fix the issue they have been trying to troubleshoot for a couple of months?

Thanks in advance for the help!!

Any ABS codes?

At this point I think I'd take it to a dealer at least for a diagnostics.

To my knowledge, no. The shop hasn't said anything about ABS codes. Why do you ask?

Are you saying for a second opinion of sorts?

I might add, that the messages are displayed, the car idles extremely rough and also tends to surge forward with a slight delay when pressure is applied to the accelerator. Another interesting fact is that after 5-7 restarts with some miles between them, the messages will go away, only to come back 2 trips later.

Yes. It seems the folks at the original shop are just chasing their tails. It wouldn't hurt to have a different set of brains evaluate the problems.

The ABS module is part of the network if it goes bad it can play havoc with the rest of the car.