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Home >> Chevrolet >> 2009 >> Traverse LS, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0638 To DTC P2635 >> DTC P0638, P2100, P2101, or P2119 >> Circuit/System Testing
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Circuit/System Testing

  1. Inspect the throttle body for the following conditions:
    • A throttle blade that is not in the rest position
    • A throttle valve that is binding open or closed
    • A throttle valve that opens or closes without spring pressure
    • If a condition is found, replace the throttle body.
    2. NOTE: Disconnecting the throttle body harness connector causes additional DTCs to set.
  2. Ignition OFF, disconnect the harness connector of the throttle body.
  3. Ignition ON, test for 4.0-5.0 V between the TAC motor control 1 circuit terminal B and ground.
    • If voltage is greater than the specified range, test each of the motor control circuits for a short to voltage. If the circuits tests normal, replace the ECM.
    • If voltage is less than the specified range, test the motor control 1 circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Connect a test lamp between the TAC motor control 2 circuit terminal A and B+. The test lamp should NOT illuminate.
    • If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  5. Test for greater than 3.5 V between TAC motor control 1 circuit terminal B and TAC motor control 2 circuit terminal A.
    • If the voltage is less than the specified value, test the motor control 2 circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  6. Ignition OFF, connect the J 34730-405  injector test lamp between the TAC motor control 1 and TAC motor control 2 circuits of the throttle body harness connector. See Special Tools . Observe the injector test lamp while turning the ignition ON for 5 seconds and then OFF. Verify the injector test lamp illuminates brightly and then turns OFF.
    • If the injector test lamp does not illuminate, replace the ECM.
  7. If all circuits test normal, replace the throttle body.
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