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Working on a 2003 GMC Sierra 2500 HD with a 6.0 L gas

engine. We are pulling code...
Working on a 2003 GMC Sierra 2500 HD with a 6.0 L gas engine. We are pulling code P0120 and P2135. We reset these codes and they come back immediately. The vehicle was towed in. Please advise. Thank you
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Answered in 6 minutes by:
3/15/2018
Ron Z.
Ron Z., - GMC Tech -
Category: GMC
Satisfied Customers: 19,962
Experience: 18+yrs experience. State Inspector & GMC Diagnostics/Repair
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Both of these codes are pointing to a problem with the throttle position sensor. Carefully inspect the electrical connector and wire harness for any loose, broken or damaged wires. If no problems are found, many time a goo d cleaning can solve this problem. Using some throttle cleaner and a toothbrush and shop rag, try to clean as much build-up from the throttle bore, plate, and plate pivot points. If the cleaning does not solve the problem, then more commonly the throttle body assembly will need to be replaced. Please be kind enough to leave a rating for our Q&A using the 'stars' at the top of the page or click 'Accept' when I have answered all your questions. A 5-star rating is very much appreciated! Rating or accepting my answer does not cost you extra.

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Customer reply replied 4 months ago
Is there any special procedure to clean the throttlebody? Is the throttle position sensor built into the throttlebody? And it has to be replaced as a whole?

It's not exactly a "special" procedure, but I'll give you the GM-recommended cleaning procedure here: https://goo.gl/ojytGT

Yes, on this vehicle the TPS is built into and part of the throttle body assembly. It has to be replaced as a whole.

Please be kind enough to leave a rating for our Q&A using the 'stars' at the top of the page when I have answered all your questions. A 5-star rating is very much appreciated! Rating my answer does not cost you extra.

Ron Z.
Ron Z., - GMC Tech -
Category: GMC
Satisfied Customers: 19,962
Experience: 18+yrs experience. State Inspector & GMC Diagnostics/Repair
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Customer reply replied 4 months ago
We’re going to replace the throttlebody. Is there any kind of relearn procedure after we replace it? We are using a dealer part

There is no special programming needed. However, GM does recommend connecting a scan-tool and verifying proper throttle-opening and throttle-closing range. This is done with key on/engine off and using the accelerator pedal while the scan-tool is connected watching the TPS.

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Customer reply replied 4 months ago
Perfect thank you I just posted another Chevy question if you want to grab it. Thank you
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