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Home >> Hummer >> 2008 >> H3 Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 50 (Cruise Control System) >> Diagnostic Information and Procedures >> DTC P0564 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Isuzu i-370, 2008 Isuzu i-290, 2008 GMC Canyon, and 2008 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition ON, at the back of the column harness connector X204 terminal A8, measure for 10 volts or greater on the cruise control supply voltage circuit.
    • If less than the specified value, test the cruise control supply voltage circuit for an open/high resistance or a short to ground.
  2. Ignition OFF, disconnect column harness connector X204.
  3. Ignition ON, verify a test lamp illuminates between B+ and the cruise control switch signal circuit connector X204 terminal B8 on the body side of the harness.
    • If the test lamp does not illuminate, test the cruise control switch signal circuit for an open/high resistance or a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition OFF, disconnect the harness connector X1 at the ECM.
  5. Verify that a test lamp does not illuminate between B+ and the cruise control switch signal circuit connector X204 terminal B8 on the body side of the harness.
    • If the test lamp illuminates, test the cruise control switch signal circuit for a short to ground.
  6. If all circuits test normal, test the component. If the circuits and the component tests are normal, replace the ECM.
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