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View Full Version : 97 Bonneville Transmission Issue: Reprogramming TCU



Suicide Bobb
09-15-2010, 03:15 PM
So I have had this issue since I got the car where it would surge down and up and down and up a few hundred rpm's every second while going up a small incline with a small amount of throttle. My buddy diagnosed it as a bad transmission torque converter solenoid. Many hours later, we replaced it.

Understanding that the previous solenoid sent improper adaptive pressure codes (not faulty, just not correct) to the transmission control unit (TCU), he said that I would have to get the TCU reset/cleared. It's a $100 job at the dealership (only place that can do it), so I figured I would run it by you guys first. Do you think that reprogramming the TCU will fix the issue?

BTW, My buddy has had 6 years of schooling in auto mechanics and 16 years of experience, so I trust his judgment, but some extra verification would be nice before I plop $100 on this repair :)

Silver
10-13-2010, 11:00 PM
?? the TCC solenoid only sends to the TCM. the TCM is what decides lock up...ect along with other modules. It may re-adapt on its own.

truckramrod
10-13-2010, 11:18 PM
That vehicle does not have a TCM, it has a pcm which controls the engine and transmission. The computer will relearn the values, just undo the battery negative cable for 1 minute. Reinstall and let the car idle for a few minutes and then drive a few miles gently.
I'm a GM tech and I own a very similar car and it has a very similiar issue, but with 184,000 miles i just let it slide.
As far as taking it to the dealer, it is unlikely that there are updated calibrations for this issue, either you guys fixed it or you didn't.

Let us know.

Suicide Bobb
10-13-2010, 11:25 PM
That vehicle does not have a TCM, it has a pcm which controls the engine and transmission. The computer will relearn the values, just undo the battery negative cable for 1 minute. Reinstall and let the car idle for a few minutes and then drive a few miles gently.
I'm a GM tech and I own a very similar car and it has a very similiar issue, but with 184,000 miles i just let it slide.
As far as taking it to the dealer, it is unlikely that there are updated calibrations for this issue, either you guys fixed it or you didn't.

Let us know.

This was a long time ago :/

I took it to the dealership, and they reset it. $300 later (after parts and the reset), it didn't fix it :( But I got it sold for $1500, and not in a sketchy way. The buyer knew what was going on.

Thanks anyways!

Silver
10-13-2010, 11:34 PM
That vehicle does not have a TCM, it has a pcm which controls the engine and transmission. The computer will relearn the values, just undo the battery negative cable for 1 minute. Reinstall and let the car idle for a few minutes and then drive a few miles gently.
I'm a GM tech and I own a very similar car and it has a very similiar issue, but with 184,000 miles i just let it slide.
As far as taking it to the dealer, it is unlikely that there are updated calibrations for this issue, either you guys fixed it or you didn't.

Let us know.

the pcm was integrated for eng and trans in 97? man i'm loosin it. i'm more 2001 and up. i will not touch a carb or even a tbi. :) gm tech here too, well former. went thru asep and all of that. since gm axed our dealer i decided to go import... good luck with them i hear alot of hairy **** going down soon with the "new" gm. dont mean to threadjack

Suicide Bobb
10-13-2010, 11:51 PM
I just hate workin on post-70s GM vehicles. It was pretty miserable.