Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connectors at the ECM.
- Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the following ground circuit terminals and ground:
- Terminal 73 X1
- Terminal 73 X2
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Verify that a test lamp illuminates between the 12V B+ circuit terminal 20 X1 and ground.
- If the test lamp does not illuminate, test the 12V B+ circuit for a short to ground or an open/high resistance.
- If all circuits test normal, replace the ECM.