I have a '98 S90 with 117K. Coming home from a trip last week the OD indicator and WSE lights started flashing and the check engine light came on. After some messing around and looking around in the FAQ I ordered a PNP switch and had a local shop put it on (too hot to spend half a day under the car, I thought). Got it back, all seemed well, but twenty miles down the road the lights started up again. I was on my way to a workshop so drove another 60 miles that way. Drove just short trips in town during the week; the next day the lights quit flashing but the CE light stayed on. Driving home the lights started up again after 15 miles.

The next day I had to make another trip, so we set out. The lights flashed all the way there, but after sitting for a few hours in the sun, they didn't come on when we started home. I stopped at an Autozone and had them read the code (my reader wouldn't pick it up) and got PO 740, TCC malfunction (this means torque converter circuit, right?). They cleared the code, we drove another 75 miles, and no lights. The transmission seems as smooth as ever, though it did seem that when the lights were blinking the RPM might have been a little higher than usual-ca. 2800 rpm at 72 rather than 2700.

Anybody got any ideas? What are my odds that it'll just stay away?

Thanks . . .

P0740 is a 'non-Volvo specific OBDII code', althought it gives some indication of the problem. Autozone's reader can't extract the codes set by the TCM.

Volvo's TCM codes for a faulty TCC are AT-331,332,333 & 341. The first three involving the Lockup Solenoid SL. If this turns out to be the problem you can replace it yourself if you are so inclined. Code At-341 is somewhat more involved.

Have you driven thru deep water lately?

The cheapest solution would be to disassemble and clean the three connectors on the drivers side of the transmission.

DEWFPO
--
1998 S90 071,245 and 1995 964 154,100

I cleaned up the connectors as best I could, but the light keeps coming on (intermittently--I've driven 100-150 miles with it off at least twice). When it comes on, the rpm's always seem to go up a little--ca. 2900 at 70 instead of 2700.

Can anybody tell me more about replacing the Lockup Solenoid? I can't find any details about it in the 700/900 FAQ.

Thanks--

Jeff

That's really helpful--thanks much. No, I haven't driven through deep water that I can recall--it's been so dry here that it's hard to find deep water these days! I'll clean the connectors and see if that doesn't help.