Testing the Serial Data Circuit for an Open/High Resistance
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2009 GMC Savana Special, 2009 GMC Savana Camper Special, 2009 GMC Savana, 2009 Chevrolet RV Cutaway, and 2009 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the appropriate harness connectors at the JX 200 splice pack.
- Install a 3 A fused jumper wire between the disconnected splice pack connector terminal 1 and a low speed GMLAN serial data circuit terminal that is not communicating.
- Ignition ON, verify the scan tool communicates with the control modules connected to the low speed GMLAN serial data circuit.
- If any control module does not communicate, test each section of the serial data circuit for an open/high resistance. If the circuits test normal, replace the control module that does not communicate when connected.
- If all circuits test normal, replace the splice pack.