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Home >> Chevrolet >> 1996 >> Astro Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0121 - TP Sensor System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. Retrieve and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. Turn ignition on, engine off. Using scan tool, read TP ANGLE value. If value is more than 2 percent, go to step 4). If value is 2 percent or less, go to next step.
  3. Observe scan tool while moving throttle from closed to wide open, and closed again. If TP ANGLE value is more than 2 percent, go to next step. If value is 2 percent or less, go to step 5).
  4. Disconnect TP sensor harness connector. If TP ANGLE value is zero percent, go to step 6). If value is more than zero percent, go to step 9).
  5. DTC P0121 is intermittent. If any additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, go to DIAGNOSTIC AIDS.
  6. Check for faulty connection at TP sensor. Repair connection as necessary and go to next step. If connection is okay, go to step 8).
  7. Repair circuit as necessary and go to step 10).
  8. Replace TP sensor and go to step 10).
  9. Replace VCM. Program replacement PCM using required equipment. Go to next step.
  10. Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0121. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2).
  11. Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.
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