TCC Test Point

[Stepperado]

I am struggling to find the test point (fuse block?) to help diagnose a problem with my torque converter clutch.

Any guidance would be appreciated.

Thanks,
Stepperado

 

[1987 GMC Jimmy]

I am struggling to find the test point (fuse block?) to help diagnose a problem with my torque converter clutch.

Any guidance would be appreciated.

Thanks,
Stepperado

I would think the test point would be Pin F (top left corner) on the ALDL connector. Use a test lamp hooked to Pin F and ground it to Pin A (top right corner). Should tell you all you need to know about the TCC.

 

[Stepperado]

OK, you got me. ALDL connector? I'm looking at my wiring schematics and in the shop manual, but I don't see anything designated as an ALDL connector.

The wiring schematic simply shows "Test Connector" 12010997.

 

[yevgenievich]

It is a diagnostic connector under the steering column. Tcc test wire should be coming out to it as mentioned above

 

[Stepperado]

Is there somewhere in the shop manual or wiring schematics that shows the pin out of this connector? I'd really like to see the assignments.

 

[yevgenievich]

Is there somewhere in the shop manual or wiring schematics that shows the pin out of this connector? I'd really like to see the assignments.

Is that for a 1984? I missed that part if it is. Need to verify, but aldl tcc test point might have been only on tbi vehicles. I will see if can find anything definitive.

 

[Stepperado]

The truck I am currently working on is an '87.

 

[yevgenievich]

You must be registered for see images attach

 

[HotRodPC]

An 84 isn't likely to have an ALDL and if it did, it's just for ESC dizzy. What exactly are you trying to test? You may need to go directly to the wire plug at the transmission.

 

[yevgenievich]

An 84 isn't likely to have an ALDL and if it did, it's just for ESC dizzy. What exactly are you trying to test? You may need to go directly to the wire plug at the transmission.

He mentioned that it is actually 87, so it should be there.

 

[HotRodPC]

He mentioned that it is actually 87, so it should be there.

Yep, I didn't see that part. 87 Should have the OBD1 ALDL for certain.

 

[Stepperado]

So are you pretty certain the pin out for the Fiero diagram (which is awesome by the way, exactly what I was hoping for) will be the same for my truck? It seems to be pretty specific as it even calls out the engine and trans of the Fiero?

 

[yevgenievich]

Connector is standard
If vehicle did not have the function, then the wire would be missing in the connector. If your connector has a pin in that spot, it should be tcc ground signal.

You must be registered for see images attach

 

[Stepperado]

yevgenievich, you 'da MAN.

Thanks so much guys.

First plan is to see if the signal (+12v) shows up when it's supposed to at the test point. If it does, according to the schematics that means my brake switch and the throttle position switch is working properly.

After the TPS, the signal splits. One leg shows up at the test point, and the other leg should be down at the transmission to assist in energizing the TCC solenoid. Looks like the ECM provides ground.

Now all I have to do is find some time to take a look.


Thanks again.

 

[Stepperado]

Oh no!! Section 10 of the 1987 Fuel, Emissions, and Drivability Manual says that the TCC System is used on the 700R4 transmissions. I did not see any mention of the system for TH400's.

Did the trucks equipped with TH400's have a lock up converter, or was this system reserved for the 700R4's in 1987? This '87 truck is new to me and I only assumed it had a TCC.

My '84 had a lock up converter and it only had a TH350 in it.