LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 1998 >> Forward Control P30, 6.5 F, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 6.5L Turbo Diesel >> Diagnostic Trouble Codes >> DTC P1654 - Service Throttle Soon Light Control Circuit >> Diagnostic Procedures
September 30: LEMON manuals is back up on a temporary server! Slowness is possible

Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, command light on and off. If light turns on and off, go to next step. If light does not turn on and off, go to step 4).
  3. DTC is intermittent. If no additional DTCs are set, see DIAGNOSTIC AIDS. If any additional DTCs are set, go to applicable DTC test.
  4. Ignition off. Unplug PCM harness connector containing the light control circuit. Turn ignition on, with engine off. If light is on, go to next step. If light is not on, go to step 7).
  5. With fused jumper wire to ground, probe light control driver circuit at PCM connector. If light is on, go to next step. If light is not on, go to step 8).
  6. Check for poor PCM connections. 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 indicator light control circuit. After repairs, go to step 10).
  8. Check for the following conditions in SERVICE THROTTLE SOON indicator light control circuit:
    • Open ignition feed circuit to bulb.
    • Faulty bulb.
    • Faulty fuse.

    After repairs, go to step 10).

  9. Replace PCM. After replacing PCM, go to next step.
  10. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, 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, repeat step 2).
  11. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
scientia non olet · About LEMON Manuals