Testing the Serial Data Circuits for a Short to Ground

WARNING: This page is about a different car, the 2015 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, all access doors closed, all vehicle systems OFF and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 2 min for all vehicle systems to power down. Disconnect the appropriate harness connectors at all low speed GMLAN serial data splice packs.
Test for infinite resistance between the serial data circuit terminal 1 at the X84 Data Link Connector and ground.
- If less than infinite resistance
  Repair the short to ground on the serial data circuit.
- If infinite resistance
Test for greater than 100 Ω between each low speed GMLAN serial data circuit at a splice pack and ground.
- If any serial data circuit is 100 Ω or less
1. Disconnect all devices on the failed serial data circuit.
2. Test for infinite resistance between each section of the failed serial data circuit and ground.
  - If less than infinite resistance, repair the short to ground in the circuit.
  - If infinite resistance
3. Connect the splice pack and connect the first device on the failed serial data circuit, ignition ON.
4. Verify the scan tool communicates or not with the low speed GMLAN serial data circuit.
  - If the scan tool does not communicate, replace the device that was just connected.
  - If the scan tool communicates and there are more devices to connect, connect the next device and repeat step 3.4.
  - If the scan tool communicates and there are no more devices to connect
5. All OK.
- If all serial data circuits are greater than 100 Ω
All OK.