computer read out
Thread Starter
5th Gear
Joined: Mar 2014
Posts: 5
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computer read out
I have a 2007c6 with 51000miles and the engine light came on. the book says it's emissions problem. I had a read out at autozone which said I had a throttle positioning problem. Does anyone know how serious this is and what they would do? the code was PO121
thank's in advance
bill kelly
thank's in advance
bill kelly
Last edited by skeeter7711; Aug 28, 2016 at 02:44 PM.
Le Mans Master
Joined: May 2016
Posts: 7,073
Likes: 1,546
From: Florida
There seems to be a repeat frequency of P2138 coming up on C6s, but since there are two main components (a send side and a receive side) to the drive by wire, further diagnosis is needed as both sides are expensive to just replace parts and hope for a hit. The throttle pedal has known to fail, but so has the TPS in the throttle body. Plus there is a known harness problem to the TB for some early years.
Last edited by BlindSpot; Aug 28, 2016 at 12:57 PM.
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
P0121 Throttle Position (TP) Sensor 1 Performance ECM
Your best bet is to take to a tech that can diagnose the problem for you. To many variables to just say what part is bad, as they are all expensive to just replace.
Your only luck would be to check the wiring harness to the TB and to look for a broken wire inside the insulation of the smaller signal wire in the area of the connector. This has been a issue in the past.
But the tech needs to look at testing procedures with the GM Tech 2 tester to get the correct diagnoses.
Your best bet is to take to a tech that can diagnose the problem for you. To many variables to just say what part is bad, as they are all expensive to just replace.
Your only luck would be to check the wiring harness to the TB and to look for a broken wire inside the insulation of the smaller signal wire in the area of the connector. This has been a issue in the past.
But the tech needs to look at testing procedures with the GM Tech 2 tester to get the correct diagnoses.
