TPS. Code 21 - Hummer Forums - Enthusiast Forum for Hummer Owners

Hummer H1 The original Hummer, which brought the Hummer look to the public eye during Desert Storm, with the addition of some features that make the H1 more of a street vehicle and less of a Army truck

Thread Tools Search this Thread
Old 11-15-2011, 08:24 PM
Thread Starter
Join Date: Mar 2011
Posts: 46
Default TPS. Code 21

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,
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Code P0171 Lean code and problem with cracked exhaust manifold Alex2012 Hummer H3 8 10-01-2012 01:53 PM
Servis TPS? Oni Hummer H3 3 01-30-2009 04:17 PM
TPS Indicator light dantstk General Hummer Talk 2 01-06-2009 02:35 PM
H3 Wheels, Tires, TPS- For Sale-$500 OBO triplej2k6 PRIVATE For Sale / Trade Classifieds 0 10-27-2008 12:28 PM
Tire Pressure Sensor (TPS) monitor - What a PITA HummerGuy Hummer H3 12 04-13-2008 05:17 PM

1995, 21, block, check, code, codes, ground, h1, h2, hummer, location, points, problems, stuck, tcm, tps

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 01:51 PM.