Canadian Hummer Club Forums

Experts-

I write to you because I am still battling some issues with my H1. A quick reminder: I own a 1995 6.5 NA that was having some tranny issues. I replaced the transmission and some of the symptoms of not shifting smoothly have vanished. As recommended, I ensured the grounding points were tight and the TPS was calibrated with the required block. I am now in a scenario where I get code 21 with the tranny stuck in safe mode. I hooked up the Tech1 with the engine off and watched the TPS voltage and % jump around and never settle down. Also, after applying the throttle it seems to get stuck at 35%. Following the manuals troubleshooting instructions I have checked for voltages and shorts. One of the last parts for troubleshooting code 21 is to jump two pins on the TCM, which I did. The result did not show a voltage greater than 4.9v per the tech manual and is hinting at a bad TCM or a possible short/ground. Have you seen symptoms like that which lead to a bad TCM? Can a TCM be tested at a dealer? Where can I buy one? How much are they? Any suggestions/tips? Part numbers? I do not have any wiring diagrams for the truck except the one for the transmission. Any help would be appreciated. Thank you in advance.



Very Respectfully,

Pavel

I believe the part number is 6004413. $440 US ish.

I wonder if a trany controller for a pre computer GM would work. I have a controller for a 4L80e from a commercial van --part no #16196390



Ports are 2 and 1.5 inch long. If this would work,I could send it to you as a tester ,or if it works $100



Have you tested the tps for a smooth operation on a sweep.The trany controller I have(aftermarket) requires a 1.0v to 4.7v sweep.This at least eliminates the tps.

Roy-

Testing another computer would be a good idea. However, I will not be around the truck till March. Once I get to it I will measure the ports and see if they are a match to the one you have above.



What do you mean a TPS sweep? I have applied the throttle to see if the TPS voltage would rise from 0.5v to 4.7v. It would do it when the truck is functioning correctly. Once code 21 returns it will not sweep from 0.5v to 4.7v smoothly. After all, maybe there is a ground issue?



-Pavel

[quote name='logicbyondreason' timestamp='1321492923' post='32762']

Roy-

Testing another computer would be a good idea. However, I will not be around the truck till March. Once I get to it I will measure the ports and see if they are a match to the one you have above.



What do you mean a TPS sweep? I have applied the throttle to see if the TPS voltage would rise from 0.5v to 4.7v. It would do it when the truck is functioning correctly. Once code 21 returns it will not sweep from 0.5v to 4.7v smoothly. After all, maybe there is a ground issue?



-Pavel

[/quote]

take a reading right from the tps sensor.You should get a resistance value that will be steady.

[quote name='Roy' timestamp='1321497224' post='32769']

take a reading right from the tps sensor.You should get a resistance value that will be steady.

[/quote]



I have done that. I made a jumper for the connection to the TPS. I then hooked up a voltmeter and watched the voltages. They were steady no fluctuations. Different story with the Tech1.