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hummer h3 3.7 P0121 error code

alrock

El Diablo
Staff member
Messages
10,677
Location
Scottsdale
Moved to the H3 section. I would double check the wiring harness and make sure no pins are bent, pulled out, damaged, etc.
 

whitesmoke

Active Member
Messages
31
Location
McAllen, Texas
I'm guessing you need a TB relearn procedure. Look it up on the web.
Chris[/QUOTE
How do you do that because I already removed the negative battery terminal and PCM-B Fuse before even installation and check engine all of a sudden turns on. After installation and check engine did the following procedure and cleaned out throttle body and check engine light disappears and all of a sudden still comes back. Mechanic recommended to replace MAP sensor ????
 
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