2000 V70 SE w/AW-55 SN; 210K miles

Transmission Mode indicator light: That's what the owner's manual calls the orange Up Arrow indicator light that goes on when any gear other than D is selected.

Anyway, the Up Arrow stayed on yesterday after upshifting to D. This was after climbing a hill in 4th and sometimes 3rd gear for about 4 miles.

The light cleared after shutting off and restarting. Hasn't repeated after that.

Any ideas?

If you were pulling a trailer or had the car loaded, it is possible that the ATF was over heated.

Without knowing the codes generated by the TCU, any answer to your problem will be a guess.

Do check the level and color of the ATF. Brown is bad, dark red is time for a flush, and pink is new.
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My name is Klaus and I am a V♂lv♂holic

"pulling a trailer or had the car loaded."

Neither. Made several high speed interstate runs of 200 + miles each, in the past month.

Would TCU codes reveal themselves with a Check Engine Light? I don't have a reader but I have a shop nearby that does.

ATF was fully flushed 6K miles ago with Mobil 3309. No episodes until now. I'll pull the dipstick and inspect, anyway.

Thanks,

If this is the original 5 speed tranny, consider yourself lucky. A good scan tool can read TCU codes, but they will probably show Pnnnn codes and those may or not be accurate. What they will tell you is that the tranny experienced a problem, which has now gone away.

If the check engine light is still on, have it checked ASAP. It might be something dumb, like a cam position sensor that is easily replaced. Or a bit more serious.
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My name is Klaus and I am a V♂lv♂holic

Yes, original 5-speed. Not babied, but it has been regularly serviced. Fluid changes every 60-70K miles. The CEL did not illuminate in this case; I was asking the question whether or not it would, with a transmission trouble code.

I pulled the dipstick and fluid is pink with no signs of overheated burnt smell.

So, will continue to drive car without concern and assume it was a one time event.

Thanks,

The CEL is only turned on in extreme cases, like the speed signal is gone or the selector indicator is haywire. A Volvo scan tool can check for any pending TCU codes.

Your arrow, not flashing, is a warning that it is not in drive mode. It could be software related, if the software has not been updated to factory specs. Usually, overheated ATF is the reason for the random arrow.

The tranny cooler imbedded in the radiator is a blessing and a curse. It helps the ATF get warm after a cold start, but it also does not cool it much below the antifreeze temperature. I would have liked to see Volvo incorporate an additional cooler line that is thermostat controlled and forward of the radiator.

Klaus
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My name is Klaus and I am a V♂lv♂holic

When the car was new, a few months after delivery in Spring 2000, it developed very harsh shifting behavior that required a software update. The Volvo dealer had some difficulty because the VIN for the 2000 V70 SE (Diplomat Sales) wasn't recognized at first by Volvo U.S.A. computers. It was finally resolved, the software successfully updated and car shifted normally again. That was 15 years ago.

A few weeks ago, I had the battery disconnected while doing electrical work in the engine compartment and cleaning/tightening all of the ground connections I could find.

Coincidental perhaps... I may have lost the stored adaptive shifting profile by disconnecting the battery for a couple of hours? The transmission did seem to shift a bit differently for a few days after the batt was connected again. It's back to normal now.

There are probably a couple of more updates to the software since then, but if you like the way it shifts, don't mess with it. Besides, the dealers charge an hour of labor to do that.

Every time battery connection is lost, the tranny has to re-learn.
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My name is Klaus and I am a V♂lv♂holic