So what do you all think about this comment?
http://www.volvo-forums.com/t1380-ets-light.htm

Mine quit at 60K miles, and left me stranded in limp-home mode. 125 mile flatbed ride and 1000 bucks at the dealers. Luckily, I was about 2 weeks from the end of the extended service conract. If it had lasted another thousand miles, I'd have had to eat the whole thing.
--
We have met the enemy and they is us. [Pogo] S70 T5 cop car : Rough Rider suspension, Walmart fog lights, eBay speakers, ambiance by Pall Mall, trim by Le Duc d'Tape, 8-channel THD by OEM amps

Earlier today, I paid my $787.00 membership dues to join the ETS Module Replacement Club. My car is a 1999 V70 GLT that has just over 100k on it and last Monday the ETS light came on for the first time. I checked for codes and found P1608 and P1615 indicating an internal fault with the ETS or ECM module. There were no other operational symptoms and the ETS light stayed out after I reset it. Based on all the ETS problems I've read about on this board and elsewhere, it would be reasonable to assume that it was only a matter of time until the ETS would fail. I figured it would be better to get the car to the dealer under its own power than wait until it died and have the extra expense of a towing bill. I intend to keep this car for quite awhile yet and now, a least, I feel I have removed a "time bomb" from it. The only good news is that my dealer was willing to match the FCP Groton price for the part ($485) and told me that they have never had to replace one a second time-the new ones are
supposedly better. I understand your reluctance to have a costly repair done if you don't need to but I think your ETS module could just be waiting to suprise you when you least expect it.

My ETS light has been coming intermitently for the past two months, possibly longer. Lately it's been on more than off. I took the car to my indy mechanic two weeks ago and he "cleaned out" the throttle body. The light didn't come on for about three days and then came back with regularity. The only symptoms other than the light is a slight, but consistant, hesitation that I notice at highway speed. The cruise control also won't work when the ETS light is on - guess it's somehow connected to the throttle body, which would make sense. Anyway, I'm going to shop around for a new throttle body on the internet. The best price appears to be at FCP Groton, however they are currently out of stock on the part. My indy will install the part and charge me for labor and new software installation. I'm expecting the total to be around $800 to $850. I'm not sure if that really addresses your question completely, but that's my related experience so far. Good luck!

We are all doomed for this repair, eventually. Well, at least, all of us with 99-or-newer cars.

When mine started going, the ETS light came and went over a period of six months. The car never left me stranded, and I never noticed any performance or drivability issues. But when the light started coming on and staying on, I had the ETS replaced. Luck for me, it was still under warranty.

--
Jim Rothe, '99 S70 T5M,
http://www.jimrothe.com/volvo/index.html