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Home >> Oldsmobile >> 2002 >> Intrigue GL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 3.5L >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor Circuit Insufficient Activity >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition on. Using scan tool, observe TP sensor angle parameter while slowly opening throttle to WOT. If TP sensor angle increased steadily from zero percent to 98 percent, go to next step. If TP sensor angle did not increase steadily from zero percent to 98 percent, go to step  4.
  3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. See CONDITIONS FOR RUNNING DTC . If DTC resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect TP sensor connector. Turn ignition on. Using scan tool, observe TP sensor voltage. If voltage is zero volts, go to next step. If voltage is not zero volts, to step  6.
  5. Turn ignition off. Connect a fused jumper wire between the TP sensor harness connector 5-volt reference circuit and signal circuit. Turn ignition on, with engine off. With scan tool, observe the TP sensor voltage parameter. Does scan tool indicate TP sensor voltage at 5 volts? If yes, go to step  9. If no, go to step  7.
  6. Using a Digital Multimeter (DMM), test TP sensor signal circuit for short to voltage. Did you find and correct the condition? If yes, go to step  15. If no, go to step  13.
  7. With a DMM, test TP sensor 5-volt reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  8. Test TP sensor signal circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to step  12.
  9. Test the TP sensor low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  10. Test the TP sensor 5-volt reference circuit for high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  11. Check for poor connections at TP sensor harness connector. Did you find and correct the condition? If yes, go to step  15. If no, go to step  13.
  12. Inspect for a poor connection at PCM harness connector. Did you find and correct the condition? If yes, go to step  15. If no, go to step  14.
  13. Replace TP sensor. After repairs, go to step  15.
  14. Replace PCM. Program replacement PCM. See PROGRAMMING . After repairs, go to next step.
  15. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC. See CONDITIONS FOR RUNNING DTC . If DTC runs and passes, go to next step. If DTC resets, go to step  2.
  16. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, system is okay. If any other DTCs are set, repair DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
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