Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
Failure to allow the ECM communications to completely terminate with the scan tool may result in misdiagnosis.
If DTC U0105, is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Turn OFF the ignition for until the ECM is powered down.
- Disconnect the FRP regulator in-line connector.
- Probe the solenoid control circuit terminal 2 with a test lamp connected to ground. The test lamp should not illuminate.
- If the test lamp illuminates, test the solenoid control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
IMPORTANT: A solenoid control circuit that is shorted to voltage will illuminate the test lamp on both the supply voltage circuit and the solenoid control circuit. - Turn ON the ignition.
- Connect the test lamp between the solenoid supply voltage circuit, terminal 1 and a ground. The test lamp should illuminate.
- If the test lamp did not illuminate, test the solenoid supply voltage circuit for an open or short to ground. If the circuit tests normal, replace the ECM.
- Connect the test lamp between the solenoid supply voltage circuit, terminal 1 and the solenoid control circuit, terminal 2. The test lamp should illuminate.
- If the test lamp did not illuminate, test the solenoid control circuit for an open. If the circuit tests normal, replace the ECM.
- Test the harness between the inline connector and the FRP regulator for an open or short to voltage. If the circuits tests normal, replace the FRP regulator.