LEMON Manuals: Even more car manuals for everyone
Home >> Hummer >> 2008 >> H3 Base, Standard >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Battery, Charging System And Starting System >> Diagnostic Information and Procedures >> DTC B1492 >> Circuit/System Testing

Circuit/System Testing

ECM Generator Field Duty Cycle Signal Circuit Malfunction

  1. Ignition OFF, disconnect the harness connectors at the generator and GBCM.
  2. Ignition ON, engine OFF, connect a test lamp to B+ and repeatedly probe the generator field duty cycle circuit terminal 2 of the generator while monitoring the ECM GEN-F Terminal Signal parameter. The parameter should change from less than 5 percent to greater than 95 percent.
    • If the parameter was not affected by the test lamp, test the circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Reconnect the harness connector at the GBCM.
  4. Repeatedly probe the generator field duty cycle circuit terminal 2 of the generator with the test lamp that is connected to B+, harness side while monitoring the ECM GEN-F Terminal Signal parameter. It should change from less than 5 percent to greater than 95 percent.
    • If the parameter was not affected by the test lamp, replace the GBCM.
  5. If the circuit tests normal, replace the generator.

GBCM Generator Field Duty Cycle Signal Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the GBCM.
  2. Ignition ON, engine OFF, connect a test lamp to B+ and repeatedly probe the generator field duty cycle circuit terminal B of the GBCM while monitoring the ECM GEN-F Terminal Signal parameter. The parameter should change from less than 5 percent to greater than 95 percent.
    • If the parameter was not affected by the test lamp, test the circuit for a short to voltage, short to ground, or an open/high resistance.
  3. If the circuit tests normal, replace the GBCM.
scientia non olet · About LEMON Manuals