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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (Engine Control System Self-Diagnostics - 5.7L) >> Diagnostic Tests >> DTC P1120: TP Sensor No. 1 Circuit ("Y" Body) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2000 Pontiac Firebird, 2000 Chevrolet Corvette, and 2000 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. If DTC P1515 or P1516 is also present, diagnose affected DTC first. See DTC P1515: CONTROL MODULE THROTTLE ACTUATOR POSITION PERFORMANCE ("Y" BODY)  or DTC P1516: THROTTLE ACTUATOR CONTROL (TAC) MODULE - THROTTLE ACTUATOR POSITION PERFORMANCE ("Y" BODY) . If DTC P1515 or P1516 is not present, go to next step.
    NOTE: Disconnecting throttle actuator motor will cause additional DTCs to set.
  3. Remove duct from throttle body assembly. Disconnect throttle actuator motor connector. Manually close throttle blade while monitoring scan tool TP SENSOR NO. 1 voltage display. If voltage reading is.13-.67 volt, go to next step. If voltage reading is not.13-.67 volt, go to step  7.
  4. Manually rotate throttle blade to wide open throttle. If voltage reading is 4.09-.4.87 volts, go to next step. If voltage reading is not 4.09-4.87 volts, go to step  7.
  5. Reconnect throttle actuator motor connector. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC function, then enter this DTC. Monitor scan tool while moving wiring harness and related connectors. If scan tool indicates this test failed this ignition, go to step  22. If scan tool does not indicate that this test failed this ignition, go to next step.
  6. While monitoring scan tool, fully open and close throttle. If scan tool indicates this test failed this ignition, go to step  32. If scan tool does not indicate that this test failed this ignition, see DIAGNOSTIC AIDS .
  7. Disconnect TP sensor connector. Using DVOM, check voltage between battery ground and TP sensor No. 1 signal circuit. If voltage reading is 3.94-6.06 volts, go to step  12. If voltage reading is not 3.94-6.06 volts, go to next step.
  8. Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Turn ignition on, with engine off. Using DVOM, check voltage between battery ground and TP sensor No. 1 signal circuit connector. If any voltage is present, go to step  26. If no voltage is present, go to next step.
  9. Using DVOM, check continuity of TP sensor No. 1 signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step  27.
  10. Check for continuity between battery ground and TP sensor No. 1 signal circuit. If continuity exists, go to step  28. If continuity does not exist, go to next step.
  11. Check for continuity between TP sensor No. 1 signal circuit and all other circuits in both TAC module harness connectors. If continuity exists between any circuit(s), go to step  30. If continuity does not exist between any circuit, go to step  33.
  12. Using DVOM, check voltage between battery ground and TP sensor No. 1 5-volt reference circuit. If voltage reading is 3.94-6.06 volts, go to step  17. If voltage reading is not 3.94-6.06 volts, go to next step.
  13. Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Turn ignition on, with engine off. Using DVOM, check voltage between battery ground and TP sensor No. 1 5-volt reference circuit connector. If any voltage is present, go to step  23. If no voltage is present, go to next step.
  14. Using DVOM, check continuity of TP sensor No. 1 5-volt reference circuit. If continuity exists, go to next step. If continuity does not exist, go to step  24.
  15. Check for continuity between battery ground and TP sensor No. 1 5-volt reference circuit. If continuity exists, go to step  25. If continuity does not exist, go to next step.
  16. Check for continuity between TP sensor No. 1 5-volt reference circuit and all other circuits in both TAC module harness connectors. If continuity exists between any circuit(s), go to step  30. If continuity does not exist between any circuit, go to step  33.
  17. Using DVOM, check resistance between battery ground and TP sensor No. 1 ground circuit. If resistance is 0-5 ohms, go to step  19. If resistance is not 0-5 ohms, go to next step.
  18. Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Check continuity of TP sensor No. 1 ground circuit. If continuity exists, go to step  33. If continuity does not exist, go to step  29.
  19. Using scan tool, monitor TP sensor No. 1 voltage. Connect a fused jumper wire between TP sensor No. 1 signal and ground circuits. If voltage reading is zero volts, go to next step. If voltage reading is not zero volts, go to step  34.
  20. Reconnect TAC module connector containing APP sensor circuits. Using scan tool, monitor APP sensor No. 1, No. 2 and No. 3 voltages. Connect a fused jumper wire between TP sensor No. 1 connector, signal and ground circuits. If any voltage is affected when signal circuit is grounded, go to next step. If voltage is not affected, go to step  31.
  21. Turn ignition off. Disconnect Throttle Actuator Control (TAC) module connector. Check continuity of TP sensor No. 1 signal circuit and all other circuits in both TAC module connectors. If continuity exists between any circuit(s), go to step  30. If continuity does not exist between any circuit, go to step  34.
  22. Repair harness and connectors as necessary. After repairs, go to step  35.
  23. Repair short to voltage in 5-volt reference circuit. After repairs, go to step  35.
  24. Repair open 5-volt reference circuit. After repairs, go to step  35.
  25. Repair short to ground in 5-volt reference circuit. After repairs, go to step  35.
  26. Repair short to voltage in signal circuit. After repairs, go to step  35.
  27. Repair open signal circuit. After repairs, go to step  35.
  28. Repair short to ground in signal circuit. After repairs, go to step  35.
  29. Repair open ground circuit. After repairs, go to step  35.
  30. Repair circuit(s) shorted together. After repairs, go to step  35.
  31. Check for poor terminal connections at TP sensor harness connector. Repair or replace terminals. After repairs, go to step  35. If terminals are okay, go to next step.
  32. Replace throttle body assembly. After replacing throttle body, go to step  35.
  33. Check for poor terminal connections at TAC module harness connector. Repair or replace terminals. After repairs, go to step  35. If terminals are okay, go to next step.
  34. Replace TAC module. After replacing module, go to next step.
  35. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions that set this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step  2.
  36. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.
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