Theory Of Operation
WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.
The Anti-lock Brake System (ABS) Module has a special diagnostic mode called "in-plant mode" for the ABS Module and the Electric Parking Brake (EPB) portion of the ABS Module. Whenever any ABS Module diagnostic routine is run the ECU will stop normal operation and enter this mode. Partial EPB functions will be disabled while in this mode. This is so that the technician can work on the vehicle knowing that the parking brake will not automatically readjust itself. The Service Electric Parking Brake Message will be displayed on the cluster when this fault is first active.