TPS sensor with an engine code P0123?

1996 CHEVROLET SILVERADO
289,000 MILES • 7.4L • V8 • 4WD • AUTOMATIC
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RENNER13
  • MEMBER
  • 2 POSTS
I lost my "passing gear" and ended up with an engine code P0123. After testing the TPS I found that my reference wire (grey) reads 5.05v and my signal wire (blue) is reading: starting at 4.95v and when adjusting the butterfly, it rises to 5.05. The black wire is also reading 5.05. when i disconnect the plug from the TPS the signal and black wire lose voltage. Any suggestions?
Jul 19, 2022 at 3:31 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
It sounds like the TPS sensor is bad. Here are instructions on how to change the sensor out in the diagrams below. It looks like it self-calibrates. Check out the diagrams (below). Please let us know what happens.

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Jul 20, 2022 at 1:29 PM
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RENNER13
  • MEMBER
  • 2 POSTS
I found the issue. My ground circuit back ECM was bad. No continuity from TPS to ECM. Bypassed wire, spliced into ets and all is well. Thank you for your response and your time.
Jul 20, 2022 at 3:17 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
Jul 21, 2022 at 10:27 AM
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