DTC U1301: Class-2 Serial Data Link High

NOTE: Sensing and Diagnostic Module (SDM) sets DTC U1300 for a short to ground or short to voltage on class-2 serial data link. If class-2 serial data link is shorted to voltage, SDM will set DTC U1300 and BCM will set DTC U1301.

Perform VEHICLE ON-BOARD DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If vehicle on-board diagnostic system check has been performed, attempt to establish communication with BCM, PCM or SDM. If communication can be established with BCM, PCM or SDM, class-2 serial data link is not shorted at this time. Go to next step.
To aid in diagnosing an intermittent, turn ignition on. Using scan tool, select DIAGNOSTIC CIRCUIT CHECK- - -CLASS 2 MESSAGE MONITOR and monitor any modules on class-2 serial data link. If INACTIVE is displayed on all modules, class-2 serial data link is currently shorted to voltage. Check for intermittent short to voltage in Purple wire between BCM and all other modules on class-2 serial data link. See WIRING DIAGRAMS . Controller name will not be displayed until ignition is on and scan tool receives correct module ID over class-2 serial data link. Repair as necessary and retest operation.