1G How to check and see if tcu is dead?

[92GSXman]

I tried to see if my tcu had any codes stored by using the write up on www.plymouthlaser.com. It said that I should get short flashes only if everything was OK. Mine doesn't do anything at all. I'm sure it was hooked up correctly. Does this mean that the tcu is bad? How can I tell for sure? Oh yeah, it's a 92 tsi awd auto tranny.

 

[Bobster66]

If you are not getting any reading from the TCU then it is probably dead. The tranny will also be in Limp Mode. If the tranny is shifting fine then you are connecting to the wrong pins or you have not turned the ignition on (I usually forget to do this first also).

 

[Froyd79]

What is your car doing that warrants the checking of the tcu? Just off hand I was thinking that if it is running fine the tcu is probably good. However the voltmeter test isnt accurate. You will have to have a trans shop run a scanner on it to be positive.

 

[92GSXman]

Well I just bought the car and the t-fer case had metal particles in it so I'm currently getting that fixed under the recall. The car was very sluggish and would barely move under it's own power. I didn't drive it far because I didn't want to screw anything up any worse that it already was. Not sure if it was in limp mode or not because I only drove it from my backyard to my shop which is about 50 feet. I got it here on a roll back. I'm sure I had the volt meter hooked up correctly bacause I also checked my ecu and got only short pulses which tells me it works fine, tried the tcu and got nothing. I'll probably pull it out and open it up today and see if it looks corroded inside.

 

[Hummer]

Well I just bought the car and the t-fer case had metal particles in it so I'm currently getting that fixed under the recall. The car was very sluggish and would barely move under it's own power. I didn't drive it far because I didn't want to screw anything up any worse that it already was. Not sure if it was in limp mode or not because I only drove it from my backyard to my shop which is about 50 feet. I got it here on a roll back. I'm sure I had the volt meter hooked up correctly bacause I also checked my ecu and got only short pulses which tells me it works fine, tried the tcu and got nothing. I'll probably pull it out and open it up today and see if it looks corroded inside.

Not sure of the relationship between the T-case and a possible TCU issue? Anyway, have to drive the car more than "50 feet" to find if the trans is in "limp mode". Starts out in third gear and never changes when in limp mode, is that not right? Good luck on the TCU check, not sure if I have a 1G in inventory?

Bob

 

[92GSXman]

Yeah, I figured I'd get the t-case issue straight and then take the car out and drive it to see if it's limp mode or not. I guess if the tcu ends up being bad I'll see if our buddy Adrian can do anything with it. I'll hollar at you later on this afternoon if you're around the house Bob.

 

[92GSXman]

UPDATE!!!! Just in case anyone needs to know how to check a tcu out in the future here's what a local repair guy told me. Open the case up and look over it very well with a flashlight. If you see anything that's corroded theres a good chance it's garbage. I had a leaking capacitor that pretty much fried my tcu. So now I've found a transfer case full of metal and a fried tcu, no wonder the car would barely move. I love DSM's

 

[steve]

Yep, the TCUs use the same caps that leak all over the ECU's. Like the ECU's it not a matter of if but when they will leak and take it out. Unlike the ECU, when the capacitor leaks in the TCU it often puts 12v on the 5v power bus and frys everything. So replace it before that happens...

Steve