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Home >> Chevrolet >> 2009 >> Traverse LS, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 138 (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 2011 GMC Acadia, 2011 Chevrolet Traverse, and 2011 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 G13 generator B+ terminal A X2 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for greater than 100 Ω between the B+ circuit and ground.
      • If 100 Ω or less, repair the short to ground on the circuit.
      • If greater than 100 Ω, replace the generator.
    • If the test lamp illuminates 
  2. Ignition OFF, disconnect the X1 harness connector at the generator, ignition ON, command the GEN-L Terminal circuit ON to 85% with a scan tool.
  3. Test for 3.5V or greater between the control circuit terminal 1 X2 and ground.
    • If less than 3.5V 
    1. Ignition OFF, disconnect the harness connectors at the ECM.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If greater the 2 Ω, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the ECM.
    • If 3.5V or greater 
    1. Ignition OFF, disconnect the harness connectors at the ECM.
    2. Test for less than 1 V between the control circuit and ground.
      • If less than 1 V, replace the G13 Generator.
      • If 1 V or greater, repair the short to voltage on the circuit.