Section 79.1
SPN 973/FMI 9

This fault is typically the J1939 EBC1 (Engine Brake Switches) is missing.‪

Section 79.1.1
Missing EBC1 (Engine Brake Switches) via J1939

Check as follows:‪

1. Check for multiple codes:
   1. If CPC SPN 168/FMI 0/14/18 (Battery Voltage) are present troubleshoot these first.
   2. If MCM SPN 625/FMI 9 is present, troubleshoot and repair the CAN line.
   3. If only SPN 973/FMI 9 is present, go to step 2 .
2. Has the CPC been recently reprogrammed?
   1. If yes, ensure the CPC Group PGR001 parameter “EBC1 Source Address SAE J1939” is configured properly: 33 = non multiplex switches, 49 = multiple switches.
   2. If no, connect ServiceLink to determine which modules are configured for the vehicle and their communication status. Once this is done, follow the appropriate module communication troubleshooting procedures for the affected module.