The ETS light or "I need a Volvo V70 turbo guru"

My sister has a 99 Volvo V70 turbo, B5254 engine, automatic trans, 203K. Runs fine until it doesnt, the ETS warning light comes on and puts the car into "limp home" mode, basically locking out 1st and second and starting the car in 3rd gear or higher. Thinking the Electronic Throttle Body (ETS) may be the culprit, i find a yellow label (supposedly the ones that got the factory fix) throttle body in the local pick n pull and swap it over, change out the Fuel and Main relays and start it up. It runs but has a misfire, so i take it down to Advance-O-Zone to get the codes read and buy a coil pack. (didn't bring my code reader to her place) other codes are for the O2 sensor and the Vehicle Speed Sensor. Drives just fine on the way there and back to her house, with a misfire on cylinder #1. Replace the coil pack and test drive again, misfire is gone, runs up and down the gears with no problems. However if I shut the car off and immediately start it back up, it goes into "limp home" mode. So i limp it back to her house, and replace the Vehicle Speed Sensor with a spare i got from the Pick n pull (from the same vehicle i pulled the Throttle body from). Start it up and test drive, no problems. Get it back in her driveway, shut it off and start it again, back to "limp home" mode. So now i'm thinking either i got another bad throttle body (but i don't think so) or I have a bad Transmission control module (which is what i do think). I don't want to pay $400-500 bucks for an Xemodex, which is touted as the next best thing to a cure for cancer for Volvo 70-series cars if I don't need it, and i seem to be running out of parts to throw at this thing. Any suggestions from the GRM hive mind?

I know i'm answering my own post, but after searching the interwebz I might check to see if this car has a faulty/failing MAF and go from there. It seems to be an issue that either accompanies the Electronic Throttle Body (ETS) failure or causes some of the symptoms of failure.

http://www.matthewsvolvosite.com/

Go there, join, ask questions. Good luck.

I feel your pain. The ex-g/f's similar '96 850 wagon was one of the most frustrating cars I've ever worked on. It had a similar transmission problem that was eventually fixed by replacing the transmission.

In reply to Ian F:

That was the first stop this morning, really hoping it's control modules/electrics and not a transmission. Since it's an intermittent problem i'm leaning in that direction

I hope so for your (or your sister's) sake. We replaced every sensor we could and the control module (at no small expense) before finally throwing in the towel and giving the car to a local indy Volvo shop. They fiddled with it some more before finally determining the trans was done.

However, her problem was less intermittent and more predictable. We would clear the codes, drive the car for a bit and it would be great until the fluid warmed up - then it would throw codes and go into limp mode.

Ugh, that sucks..