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Home >> Chevrolet >> 2000 >> Chevy Express G2500, Van Cargo Extended, 6.5 F >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - Diesel >> Diagnostic Tests >> DTC P0221: Accelerator Pedal Position Sensor 2 Circuit Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. If OBD system check has been performed, go to next step. If OBD system check has not been performed, see ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool. Turn ignition on. Using scan tool, with throttle closed, observe APP sensor voltages. APP 1 sensor voltage should be .45-.95 volt. APP 2 sensor voltage should be 4.0-4.5 volts. APP 3 sensor voltage should be 3.6-4.0 volts. If voltages are as specified, go to next step. If voltages are not as specified, go to step  4.
  3. DTC is intermittent. If no additional DTCs are set, see DIAGNOSTIC AIDS . If any additional DTCs are set, perform appropriate DTC test.
  4. Turn ignition off. Disconnect APP sensor harness connector. Turn ignition on. Measure voltage between ground and each 5-volt reference circuit at APP sensor harness connector. If voltage on all circuits is 4.75 volts, go to next step. If voltage on all circuits is not 4.75 volts, go to step  6.
  5. Turn ignition on. Using test light connected to battery positive, probe each at APP sensor harness connector. If test light illuminates on all circuits, go to step  9. If test light does not illuminate on all circuits, go to step  8.
  6. Turn ignition off. Disconnect PCM harness connectors. Check for open or short to ground in 5-volt reference circuits. Repair as necessary. After repairs, go to step  11. If circuits are okay, go to next step.
  7. Check 5-volt reference circuits for poor connections at PCM. Repair as necessary. After repairs, go to step  11. If connections are okay, go to step  10.
  8. Turn ignition off. Disconnect PCM harness connectors. Check for open in sensor ground circuits. Repair as necessary. After repairs, go to step  11. If circuits are okay, go to step  10.
  9. Replace APP module. See ACCELERATOR PEDAL POSITION MODULE  After repairs, go to step  11.
  10. Replace PCM. Perform PCM relearn procedures. See PROGRAMMING . After repairs, go to next step.
  11. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0221. 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, go to step  2.
  12. Using scan tool, check for DTCs. If any undiagnosed DTCs are set, perform appropriate DTC test. If no DTCs are set, system is okay.
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