Circuit/System Testing
NOTE:
Use the DTC Descriptors and Diagnostic Aids above to determine the control module which is not communicating and should be tested. Use the schematics to identify the following:
- Control modules the vehicle is equipped with
- Control module locations on the Chassis high speed GMLAN serial data circuits
- The control module serial data circuit terminals
- Ignition OFF, disconnect the harness connector at the non communicating control module.
- Test for less than 5 Ω between the ground circuit terminal 6 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.
- If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the electronic brake control module (EBCM).
- Ignition OFF, test for less than 1 Ω in each serial data circuit between the non communicating control module and the control module setting the DTC.
- If greater than the specified range, test the serial data circuits for an open/high resistance.
- If all circuits test normal, replace the non communicating control module.