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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 87 (Engine Controls - Self-Diagnostics - 6.6L Diesel) >> Diagnostic Tests >> DTC P1643: Wait To Start Indicator Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Ensure that the engine is not at full operating temperature. Observe the Wait to Start lamp while turning ON the ignition. Does the Wait to Start indicator turn ON and then turn OFF? If yes, go to next step. If no, go to step  4.
  3. The DTC is intermittent. If no additional DTCs are stored, see DIAGNOSTIC AIDS . If additional DTCs were stored refer to those tables. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  4. Does the Wait to Start indicator stay ON? If yes, go to step  7. If no, go to next step.
  5. Disconnect the ECM connector containing the Wait to Start lamp control circuit. Turn ON the Ignition, with the engine OFF. Probe the Wait to Start indicator control circuit in the ECM harness connector with a fused jumper connected to a good ground. Does the Wait to Start lamp illuminate? If yes, go to next step. If no, go to step  8.
  6. Inspect for poor connections at ECM. Repair as necessary. Did you find and correct the condition? If yes, go to step  10. If no, go to step  9.
  7. Inspect the control circuit of the Wait to Start indicator for a short to ground. Repair as necessary. Did you find and correct the condition? If yes, go to step  10. If no, go to step  9.
  8. Check the Wait to Start indicator circuit for the following conditions:
    • An open ignition 1 voltage circuit to the bulb.
    • A malfunctioning bulb.
    • The control circuit open or shorted to battery voltage.

    After repairs, go to step  10.

  9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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