Vehicle: 2021 Ford F350, 4WD, Super Duty, V8-6.7L DSL Turbo, Automatic Transmission/Transaxle

Mileage: 54,997

Problem: The owner of this F350 complained that the driver seat kept changing positions and the engine would not shut off, even with the key out. The battery junction box (BJB) had been replaced per Ford TSB #23-2133, but the issues persisted.

Case Details: The technician connected a scan tool and found the following diagnostic trouble codes (DTCs):

• U0151 - Lost Communication with Restraints Control Module (RCM)
• U0200 - Lost Communication with Door Control Module "B" (DCM-B)
• U0208 - Lost Communication with Seat Control Module "A"
• U0256 - Lost Communication with Front Controls Interface Module "A" (FCIM-A)
• U0452 - Invalid Data Received from Restraints Control Module (RCM)

He confirmed that the RCM, DCM, SCM and FCIM were all not communicating then gave ALLDATA Tech-Assist a call.

The consultant reviewed the wiring diagrams and determined that all the affected modules were on the MS-CAN Bus and suggested inspecting the wiring harness and connectors to each of the modules. He sent the technician this harness location image.

The technician inspected the wiring harness and found one of the MS-CAN Bus wires near the C327 connector had broken.

Confirmed Repair: After repairing the wire, the engine shut off normally and the driver’s seat position functioned as designed. Fixed!