Circuit/System Testing
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
- 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.
- Ignition OFF, disconnect the harness connector of the throttle body.
- Ignition ON, test for 4.0-5.0 V between the TAC motor control 1 circuit terminal B and ground.
- If greater than the specified range, test each of the motor control circuit terminals A and B for a short to voltage. If the circuits test normal, replace the ECM.
- If 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.
- 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.
- Test for greater than 3.5 V between TAC motor control 1 circuit terminal B and TAC motor control 2 circuit terminal A.
- If less than the specified value, test the motor control 2 circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition OFF, connect the J 34730-405
injector test lamp between the TAC motor control 1 and TAC motor control 2 circuit terminal A and B 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.
- If all circuits test normal, replace the throttle body.
NOTE:
Disconnecting the throttle body harness connector causes additional DTCs to set.