Testing the Serial Data Circuits for a Short to Ground
WARNING: This page is about a different car, the 2009 Saturn Outlook, 2009 GMC Acadia, 2009 Chevrolet Traverse, and 2009 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connectors with the high speed GMLAN serial data circuits at an easily accessible control module.
- Ignition OFF for 60 seconds, test for less than 1k Ω between each serial data circuit at the control module connector that was just disconnected and ground. Verify that one or more serial data circuits are less than 1k Ω.
- If all serial data circuits are greater than the specified range, replace the control module that was disconnected.
- Disconnect the harness connectors with the high speed GMLAN serial data circuits at another control module, in the direction of the circuit shorted to ground.
- Ignition OFF for 60 seconds, test for less than 1k Ω between the serial data circuits at the control module connector that was just disconnected and ground. Verify that one or more serial data circuits are less than 1k Ω.
- If greater than the specified range for all serial data circuits, replace the control module that was just disconnected.
- Repeat step 3 until one of the follow conditions are isolated:
- A short to ground on the serial data circuit between 2 control modules
- A short to ground on the serial data circuit between a control module and a terminating resistor.