I am working on a friend's 2005 S80 2.5T FWD with only 70k miles (immaculate/like showroom new), and while driving it quit and wouldn't re-start, but finally started and ran rough, but he got it to a shop at reduced speed.

It had the "Reduced Engine Performance" illuminated

They pulled the following DTCs
1) 925C Elect Throttle Module Unit Signal Too High
2) 9200 Throttle Position Sensor Faulty Signal
3) Elect Throttle Unit Potientiometer 2 Faulty Signal
4) Throttle Unit Faulty Signal

They printed on the invoice : " Vehicle will need a throttle body"

They and the dealer wanted almost $1500 for a new ETM installed.

So knowing I have a commercial level shop, and knowing I'd had problems with my 2001 S60 T5 with my ETM, he asked me to install a new ETM for him, which I did.

When I got the car at my shop, it was running w/ no codes (the shop had reset all of them and they hadn't returned) , but the rpm was wandering and it had hesitation.

I changed the ETM (new Bosch "Plug-n-Play unit- NO computer flash req'd) and it ran like a kitten. I drove the car about 30mi and it was delightful. The battery was weak (low battery warning on cluster), so I fitted a new battery (The old one was the original 12+ year old battery!). I didn't hook up an aux battery during the switch (so the car lost power during the brief swap), and when I turned the ign on I had 3 DTCs, and I think they were:

1) 9270 Throttle Valve Faulty Signal
2) 925C Throttle Valve Signal Too High
3) can't remember

and the car was running VERY rough (like 4 out of 5 cylinders firing).

Figuring the battery change cause a "brain fart" in the computer, I reset the codes, at which point the car started and ran perfectly.

The owner picked up the car and drove it 20mi over a 4 day period.

Tonight he called me and said he was broken down (again) on the side of the road, and the Reduced Performance was showing and the car would barely idle, and the car would not move at all.

I drove out to rescue him and I observed the following DTCs

1) ECM-9270 Throttle Valve- Faulty Signal
2) ECM- 925C Throttle Valve- Signal too High
3) ECM-440B Fuel Level Sensor- Signal Missing

We also had an Intermittent Fault CEM-3F02 Shift Lock Signal Too High

I tried resetting the DTCs, but the car barely ran (like it was running on 3 of its 5 cylinders- REALLY REALLY rough, and the exhaust smelled of raw fuel), and the throttle pedal had absolutely NO effect on RPM like it was disconnected completely.

I disconnected the ETM at the unit a few times, reset the DTCs a few times, and sometimes the car would sort-of run (1400rpm idle, it would accelerate w/ throttle pedal).

After about 5 times doing this, after resetting any DTCs the car ran like a kitten again, and my friend drove home, with no DTCs showing.

At times, even with DTCs showing, the Check Engine light was NOT illuminated, which I thought was strange.

Obviously, we have ZERO confidence that the car will continue to run normally at this point.

I seriously doubt the new ETM is bad, and I question that the old one was ever bad, but we no longer get several of the "old" ETM codes the previous unit threw.

So, after all of this, does this ring any bells, and where would YOU go from here if you were I??