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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 213 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0221: App Sensor No. 2 Circuit Performance >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  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 .
  2. Is DTC P0121 also set? If yes, go to step  6. If no, go to next step.
  3. Turn ignition off. Turn ignition on, with engine off. Observe the TP sensor 2 voltage with a scan tool. Slowly depress the accelerator pedal to Wide-Open Throttle (WOT), then slowly return the pedal to closed throttle. Does the TP sensor 2 voltage decrease as the pedal is depressed and increase as the pedal is released? If yes, problem is intermittent. Refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L & 3.0L VUE article. If no, go to next step.
  4. Turn ignition off. Disconnect the throttle body harness connector. Turn ignition on, with engine off. Observe the TP sensor 1 voltage with a scan tool. Is the TP sensor 1 voltage about zero volts? If yes, go to next step. If no, go to step  11.
  5. Turn ignition off. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the TP sensor 2 and the signal circuit of the TP sensor 2. Turn ignition on, with engine off. Observe the TP sensor 2 voltage. Is the TP sensor 2 within 4.8-5.2 volts? If yes, go to step  10. If no, go to next step.
  6. Measure the voltage from the 5-volt reference of the TP sensor to a good ground with the DVOM. Is the voltage about 5 volts? If yes, go to next step. If no, go to step  13.
  7. Turn ignition off. Allow the ECM to completely power down. This can be verified by the loss of communication on the scan tool. Measure the resistance from the low reference circuit of the TP sensor to a good ground with the DVOM. Is the resistance less than 5 ohms? If yes, go to next step. If no, go to step  16.
  8. Idle the engine. Observe the MAF sensor g/s with a scan tool. Increase the engine speed slowly to 3000 RPM, then back to idle. Does the MAF sensor g/s change smoothly and gradually through 7-40 g/s of the test? If yes, go to step  11. If no, go to DTC P0101: MASS AIRFLOW SYSTEM PERFORMANCE .
  9. Test the signal circuit of the TP sensor 1 for a short to ground. Did you find and correct the condition? If yes, go to step  19. If no, go to step  17.
  10. Test the signal circuit of the TP sensor 1 for a short to voltage. Did you find and correct the condition? If yes, go to step  19. If no, go to step  17.
  11. Test the signal circuit of the TP sensor 1 for a short to ground, short to low reference circuit, high resistance, or an open circuit. Repair as necessary. Did you find and correct the condition? If yes, go to step  19. If no, go to step  14.
  12. Test the 5-volt reference circuit of the TP sensor for a short to ground, high resistance, or open circuit. Repair as necessary. Did you find and correct the condition? If yes, go to step  19. If no, go to next step.
  13. Test the 5-volt reference circuit of the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  19. If no, go to step  17.
  14. Test for an intermittent and for a poor connection at the TP sensor. Did you find and correct the condition? If yes, go to step  19. If no, go to next step.
  15. Replace throttle body assembly. After replacing the throttle body assembly, go to step  19.
  16. Repair the open or high resistance in the low reference circuit. After repairs, go to step  19.
  17. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step  19. If no, go to next step.
  18. Replace ECM. Perform ECM relearn procedures. See ENGINE CONTROL MODULE  under PROGRAMMING. After replacing ECM, go to next step.
  19. Clear the DTCs with a scan tool. Turn ignition off. Start engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  20. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, diagnose affected DTC(s). See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
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