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  #1  
Old 06-20-2015, 07:09 PM
stawgn10 stawgn10 is offline
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AA794 TCU testing?

Is there a way to test a tcu out of the car before installing it? I had a code 24 and the binding when putting it into park from drive. It would also rock backwards when the engine was shutdown, but all of it would go a way when I put the fwd fuse into the slot. So I figured it wasn't the solenoid. No more rocking, no more binding, no more power light flashing, no more skidding forward on tight turns, etc... So I was going to try swapping out the tcu. So I was wondering, since any tcu I get is going to be used is there a way to test it outside of the car to insure it is good?

Any other ideas to try before I replace the tcu?

Thanks,
Tom
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Old 06-21-2015, 09:43 AM
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longassname longassname is offline
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Re: AA794 TCU testing?

For the longest time I never saw TCUs go bad. Then starting a few years ago I started hearing more and more reports of bad TCUs. I've seen a few myself now. In every one I've seen the failure was caused by a leaking aluminum capacitor. When they leak the fluid corrodes the traces on the circuit board and destroys the TCU.

Aluminum capacitors just don't last forever and when they leak they destroy the electronic device they are in. It's a common scenario in electronics. I'm not saying your TCU is bad but since you suspect it is bad I would open it and look at it to see if any of the capacitors have leaked.

It's become a common enough problem that I recently put in the research to identify what the OE capacitors are and procure a stock of them. I'm going to start pro-actively replacing them in every TCU I socket for a performance chip.
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Old 06-23-2015, 07:49 PM
stawgn10 stawgn10 is offline
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Re: AA794 TCU testing?

Thanks, I'll have to open mine and take a peek.
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Old 06-27-2015, 04:16 PM
92snowmachine 92snowmachine is offline
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Re: AA794 TCU testing?

I have an ecutune ecu in mine but paid the core to keep mine so I had a backup. It was working fine when I took it out but wanted to protect my newly rebuilt transmission. I could send you mine for testing purposes if you need it.
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Old 07-11-2015, 01:29 AM
stawgn10 stawgn10 is offline
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Re: AA794 TCU testing?

Quote:
Originally Posted by 92snowmachine View Post
I have an ecutune ecu in mine but paid the core to keep mine so I had a backup. It was working fine when I took it out but wanted to protect my newly rebuilt transmission. I could send you mine for testing purposes if you need it.
Sorry, I never subscribed to this page and I haven't check this in a while. I appreciate the offer of using your TCU to test mine. Is yours an AA794 or does it make a difference?

Thanks,
Tom
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Old 07-11-2015, 10:27 PM
92snowmachine 92snowmachine is offline
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Re: AA794 TCU testing?

i dont think it makes a difference but will find mine and see what it says on it.
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Current Stable:
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1979 K5 Blazer Cheyenne
1956 Plymouth Belvedere - Daisy
1967 Chevy C20
1953 Chevy 210
1969 Plymouth Satellite
1949 Chevy Thriftmaster
1959 Chevy Apache
1951 Chevy Stepside
1969 Chevy Camper Special
1978 Ford F150 w/ stroked 460
1986 Volvo 740 turbo wagon
1999 GMC 2500 Creep Van
1994 Impreza Outback
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  #7  
Old 07-12-2015, 10:53 PM
stawgn10 stawgn10 is offline
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Re: AA794 TCU testing?

I'll be out of town next week, but I'll pm you when I get back and see about using your tcu to troubleshoot the tranny.

Thanks again,
Tom
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