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Home >> Oldsmobile >> 2001 >> Bravada >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 4.3L >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
    2. NOTE: If any other DTCs are set, diagnose affected DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  2. Using scan tool, observe TP sensor angle parameter while slowly opening the throttle to WOT. If TP angle increases steadily and evenly from the closed throttle value of zero percent to WOT throttle value of greater than 98 percent, go to next step. If TP angle does not increase steadily and evenly from the closed throttle value of zero percent to WOT throttle value of greater than 98 percent, go to step  4.
  3. Observe the FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running the DTC or as closely as possible to FREEZE FRAME/FAILURE RECORDS conditions. See CODE ENABLE CRITERIA . If DTC resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If voltage parameter is zero volts, go to next step. If voltage parameter is not zero volts, go to step  6.
  5. Turn ignition off. Connect a fused jumper between TP sensor harness connector terminals "A" (Black wire on "L" and "M" Series; Gray wire on "S" and "T" Series) and "C" (Dark Blue wire). See Figure. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If voltage parameter is 5 volts, go to step  9. If voltage parameter is not 5 volts, go to step  7.
  6. Turn ignition off. Using a DVOM, check Dark Blue wire for short to voltage. Repair as necessary. After repairs, go to step  14. If circuit is okay, go to step  12.
  7. Turn ignition off. Using DVOM, check Gray wire for open or high resistance. Repair as necessary. After repairs, go to step  14. If circuit is okay, go to next step.
  8. Check Dark Blue wire for open or high resistance. Repair as necessary. After repairs, go to step  14. If circuit is okay, go to step  11.
  9. Turn ignition off. Check Black wire for open and high resistance. Repair as necessary. After repairs, go to step  14. If circuit is okay, go to next step.
  10. Check for a faulty connection at TP sensor harness connector. Repair as necessary. After repairs, go to step  14. If connection is okay, go to step  12.
  11. Check for a faulty connection at PCM harness connector. Repair as necessary. After repairs, go to step  14. If connection is okay, go to step  13.
  12. Replace TP sensor. After replacing sensor, go to step  14.
  13. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running the DTC. See CODE ENABLE CRITERIA . If DTC test runs and passes, go to next step. If DTC resets, go to step  2.
  15. Using scan tool, observe the stored information and Capture info. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
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