Testing the Serial Data Circuit for an Open/High Resistance
WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
- If equipped with a second splice pack, ignition ON, verify the scan tool communicates with one or more control modules connected to the second splice pack.
- If all control modules on the second splice pack do not communicate, test the serial data circuit between the first and second splice packs for an open/high resistance. If the circuit tests normal, test the second splice pack for an open/high resistance. If the splice pack tests normal, replace any module or component that may be between those two splice packs.
- If equipped with a third splice pack, ignition ON, verify the scan tool communicates with one or more control modules connected to the third splice pack.
- If all control modules on the third splice pack do not communicate, test the serial data circuit between the second and third splice packs for an open/high resistance. If the circuit tests normal, test the third splice pack for an open/high resistance. If the splice pack tests normal, replace any module or component that may be between the those two splice packs.
- Ignition OFF, disconnect the splice pack containing the serial data circuits to the modules that are not communicating.
- Install a 3 A fused jumper wire between the splice pack connector serial data input terminal and a low speed GMLAN serial data circuit 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.