LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Hummer >> 2003 >> H2 >> Repair and Diagnosis >> Electrical >> Starter >> Starters >> Diagnostic System Check - Engine Electrical >> Power Mode Mismatch >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

NOTE: This table is used if the observed vehicle power mode does not match the ignition switch position.
NOTE: Open the driver door and leave it open during this test. This will disable the RAP power mode and eliminate this power mode from the power mode parameter list.
  1. Install a scan tool. Turn OFF the ignition. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Does the displayed power mode parameter match the actual ignition switch position? If yes, go to next step. If no, go to step  6.
  2. Turn the ignition switch to the UNLOCK position. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Does the displayed power mode parameter match the actual ignition switch position? If yes, go to next step. If no, go to step  6.
  3. Turn ON the ignition, with the engine OFF. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Does the displayed power mode parameter match the actual ignition switch position? If yes, go to next step. If no, go to step  6.
    4. NOTE: The engine may start during this procedure. Turn the ignition OFF after verifying this power mode.
  4. Turn the ignition switch to the CRANK position. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Does the displayed power mode parameter match the actual ignition switch position? If yes, go to next step. If no, go to step  6.
  5. Turn the ignition switch to the ACCY position. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Does the displayed power mode parameter match the actual ignition switch position? If yes, problem is intermittent. If yes, go to next step.
    6. NOTE: The engine may start during this procedure. Turn the ignition OFF after verifying this power mode.
  6. Turn OFF the ignition. Disconnect the PMM. Hold the ignition switch in the position that indicated the incorrect power mode. With a test lamp attached to a good ground, test the PMM ignition switch inputs for voltage. Is voltage present on only the inputs specified for the ignition switch position? If yes, go to next step. If no, go to step  8.
    7. NOTE: The engine may start during this procedure. Turn the ignition OFF after verifying this power mode.
  7. Hold the ignition switch in the position that indicated the incorrect power mode. With a test lamp attached to a good ground, test the PMM ignition switch inputs for voltage. Refer to Body Control Module . Is voltage not present on any inputs specified for the ignition switch position? If yes, go to step  9. If no, go to step  11.
  8. Disconnect the ignition switch. Test the PMM ignition switch input circuits for a short to voltage. Test the PMM ignition switch circuits for a short between circuits. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  9. Disconnect the ignition switch. Test the PMM ignition switch input circuits for an open. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  10. Inspect for poor connections and terminal tension at the harness connector of the ignition switch. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  11. Inspect for poor connections and terminal tension at the harness connector of the PMM. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  12. Replace the ignition switch. Did you complete the replacement? If yes, go to step  14.
    13. NOTE: After replacement of the PMM perform the programming or set up procedure if required.
  13. Replace the PMM. Did you complete the replacement? If yes, go to next step.
    14. NOTE: The engine may start during this procedure. Turn the ignition OFF after verifying all power modes.
  14. Reconnect all disconnected components. With a scan tool, under the Diagnostic Circuit Check menu observe the Class 2 Power Mode parameter. Cycle the ignition switch through all possible positions one at a time. Does the displayed power mode parameter match the actual ignition switch position? If yes, system is okay. If no, go to step  1.
scientia non olet · About LEMON Manuals