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Home >> Chevrolet >> 2009 >> Traverse LS, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 27 (Battery, Charging System And Starting System) >> Diagnostic Information and Procedures >> DTC P0621 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2010 Saturn Outlook, 2010 GMC Acadia, 2010 Chevrolet Traverse, and 2010 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify that a test lamp illuminates between the generator B+ terminal 1 X2 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  2. Ignition OFF, disconnect the X1 harness connector at the generator.
  3. Ignition ON, test for less than 1 V between the generator turn ON control circuit terminal 1 and ground.
    • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Engine running, command the GEN-L Terminal circuit ON to 85% with a scan tool. Test for greater than 3.5 V between the control circuit terminal 1 and ground.
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the generator.
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