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Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. 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, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Is DTC P1518 also set? If yes, see DTC P1518: TAC MODULE SERIAL DATA FAULT . If no, go to next step.
  3. Turn ignition ON, with engine OFF. With a scan tool, observe the TP sensor 1 and 2 Agree/Disagree parameter. Does the scan tool TP sensor 1 and 2 Agree/Disagree parameter indicate Disagree? If yes, go to step  5. If no, go to next step.
  4. Remove the air inlet duct from the throttle body. Disconnect the throttle actuator motor harness connector. Slowly open the throttle blade to Wide Open Throttle (WOT) and back to the closed throttle position several times manually, while observing the scan tool TP sensor Agree/Disagree parameter. Does the TP sensor Agree/Disagree parameter change from Agree to Disagree during the above test? If yes, go to step  18. If no, go to next step.
  5. Disconnect the TP sensor harness connector. Disconnect the TAC module harness connectors. Test the TP sensor 1, 5-volt reference circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  6. Check for a short between the TP sensor 1, 5-volt reference circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  7. Check the TP sensor 1 signal circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  8. Check for a short between the TP sensor 1 signal circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  9. Check the TP sensor 1 low-reference circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  10. Check for a short between the TP sensor 1 low-reference circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  11. Check the TP sensor 2, 5-volt reference circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  12. Check for a short between the TP sensor 2, 5-volt reference circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  13. Check the TP sensor 2 signal circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  14. Check for a short between the TP sensor 2 signal circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  15. Check the TP sensor 2 low-reference circuit for resistance. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  16. Check for a short between the TP sensor 2 low-reference circuit and all other TAC module circuits. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  17. Test for an intermittent and/or poor connections at the TAC module. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  18. Test for an intermittent and/or poor connections at the TP sensor. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
    19. NOTE: The TP sensor is not a serviceable part and should only be replaced with the throttle body assembly.
  19. Replace throttle body assembly. See THROTTLE BODY under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to next step.
  20. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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 cycle? If yes, go to step  2. If no, go to next step.
  21. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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