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Home >> Chevrolet >> 2000 >> Chevy Express G3500, Van Cargo Extended, 6.5 F >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - Diesel >> Diagnostic Tests >> DTC P1654: Service Throttle Soon Light Control Circuit >> 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, command SERVICE THROTTLE SOON light on and off. If SERVICE THROTTLE SOON light illuminates, go to next step. If SERVICE THROTTLE SOON light does not illuminate, 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 PCM harness connector containing SERVICE THROTTLE SOON light control circuit. Turn ignition on. If SERVICE THROTTLE SOON light does not illuminate, go to next step. If SERVICE THROTTLE SOON light illuminates, go to step  7.
  5. Connect fused jumper wire between ground and SERVICE THROTTLE SOON light control circuit at PCM harness connector. If SERVICE THROTTLE SOON light illuminates, go to next step. If SERVICE THROTTLE SOON light does not illuminate, go to step  8.
  6. Check for poor connections at PCM. Repair as necessary. After repairs, go to step  10. If connections are okay, go to step  9.
  7. Repair short to ground in SERVICE THROTTLE SOON light control circuit. After repairs, go to step  10.
  8. Check SERVICE THROTTLE SOON light control circuit for open ignition feed circuit, faulty bulb, or open or short to battery voltage. Repair as necessary. After repairs, go to step  10.
  9. Replace PCM. Perform PCM relearn procedures. See PROGRAMMING . After repairs, go to next step.
  10. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P1654. 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.
  11. 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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