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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 P1280: Accelerator Pedal Position (App) Sensor No. 2 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.
    NOTE: If DTC P1220 or P1518 is also present, diagnose affected DTC(s) first. See DTC P1220: THROTTLE POSITION (TP) SENSOR NO. 2 CIRCUIT ("Y" BODY)  or DTC P1518: THROTTLE ACTUATOR CONTROL (TAC) MODULE SERIAL DATA CIRCUIT ("Y" BODY) .
  2. Turn ignition on, engine off. Ensure accelerator pedal is not depressed. Using scan tool in TAC DATA LIST option, monitor APP sensor No. 2 voltage. If voltage reading is 3.90-4.81 volts, go to next step. If voltage reading is not 3.90-4.81 volts, go to step  6.
  3. Fully depress accelerator pedal. Check voltage reading on scan tool. If voltage reading is 0.83-2.90 volts, go to next step. If voltage reading is not 0.83-2.90 volts, go to step  6.
  4. Turn ignition off for 15 seconds. Turn ignition on, engine off. Using scan tool, select DTC option and FAILED THIS IGNITION option. Move/wiggle harness connectors and related connectors. If this DTC sets, go to step  21. If this DTC does not set, go to next step.
  5. Slowly depress accelerator pedal to Wide Open Throttle (WOT) position then return to closed position. If this DTC sets, go to step  31. If this DTC does not set, problem is intermittent. See DIAGNOSTIC AIDS .
  6. Disconnect APP sensor harness connector. Check voltage between battery ground and APP sensor No. 2 signal circuit at APP sensor harness connector. If voltage reading is 3.94-6.06 volts, go to step  11. If voltage reading is not 3.94-6.06 volts, go to next step.
  7. Turn ignition off. Leave APP sensor connector disconnected. Disconnect TAC module harness connector containing APP sensor circuit. Turn ignition on, engine off. Check voltage between APP sensor No. 2 harness connector signal circuit and battery ground. If any voltage is present, go to step  25. If no voltage is present, go to next step.
  8. Check continuity in APP sensor No. 2 signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step  26.
  9. Check harness for continuity between APP sensor No. 2 signal circuit and battery ground. If continuity exists, go to step  27. If continuity does not exist, go to next step.
  10. Check for continuity between APP sensor No. 2 signal circuit and TAC harness connector. Check all other circuits in both TAC module harness connector. If continuity exists, go to step  29. If continuity does not exist, go to step  32.
  11. Check voltage between battery ground and APP sensor No. 2 harness connector 5-volt reference circuit. If voltage reading is 3.94-6.06 volts, go to step  16. If voltage reading is not 3.94-6.06 volts, go to next step.
  12. Turn ignition off. Disconnect TAC harness connector containing APP sensor circuits. Turn ignition on, engine off. Check voltage between battery ground and APP sensor No. 2 5-volt reference circuit at harness connector. If any voltage is present, go to step  22. If no voltage is present, go to next step.
  13. Check for continuity in harness between APP sensor No. 2 5-volt reference circuit and sensor ground. If continuity exists, go to next step. If continuity does not exist, go to step  23.
  14. Check for continuity in harness between APP sensor No. 2 5-volt reference circuit battery ground. If continuity exists, go to step  24. If continuity does not exist, go to next step.
  15. Check harness for continuity between APP sensor No. 2 5-volt reference circuit at TAC harness connector and all the other circuit in both TAC connectors. If continuity exists, go to step  29. If continuity does not exist, go to step  32.
  16. Check resistance between battery ground and APP sensor No. 2 ground circuit at APP sensor harness connector. If measured resistance is 0-5 ohms, go to step  18. If resistance is not 0-5 ohms, go to next step.
  17. Turn ignition off. Leave APP sensor harness connector disconnected. Disconnect TAC module harness connector containing APP sensor circuit. Check continuity of APP sensor No. 2 ground circuit. If continuity exists, go to step  32. If continuity does not exist, go to step  28.
  18. Using a fused jumper wire, jumper APP sensor No. 2 signal circuit to APP sensor ground circuit in harness connector. Using scan tool, monitor APP sensor No. 2 voltage. If scan tool indicates zero volts, go to next step. If scan tool does not indicate zero volts, go to step  33.
  19. Using a fused jumper wire, jumper APP sensor No. 2 signal circuit and APP sensor ground circuit. Using scan tool monitor, APP sensors No. 1 and 3 and TP sensor No. 2 voltage. If any of the sensor voltage is affected when APP sensor No. 2 signal is grounded, go to next step. If sensor voltage is not affected, go to step  30.
  20. Turn ignition off. Disconnect TAC harness connector. Check continuity between APP sensor No. 2 signal circuit at TAC harness connector, and all other circuits in both TAC module connectors. If continuity exists, go to step  29. If continuity does not exist, go to step  33.
  21. Repair harness/connections as necessary. After repairs, go to step  34.
  22. Repair short to voltage in 5-volt reference circuit. After repairs, go to step  34.
  23. Repair open or high resistance in 5-volt reference circuit. After repairs, go to step  34.
  24. Repair short to ground in 5-volt reference circuit. After repairs, go to step  34.
  25. Repair signal circuit for short to voltage. After repairs, go to step  34.
  26. Repair open or high resistance in signal circuit. After repairs, go to step  34.
  27. Repair short to ground in signal circuit. After repairs, go to step  34.
  28. Repair open or high resistance in ground circuit. After repairs, go to step  34.
  29. Repair circuits that are shorted together. After repairs, go to step  34.
  30. Check for poor connection at APP sensor harness connector. Repair as necessary. After repairs, go to step  34. If connection is okay, go to next step.
  31. Replace accelerator pedal assembly. After replacing pedal assembly, go to step  34.
  32. Check for poor connection at TAC module harness connector. Repair as necessary. After repairs, go to step  34. If connector is okay, go to next step.
  33. Replace TAC module. After replacing module, go to next step.
  34. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting 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.
  35. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
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