System Operation
Power Running Board (PRB) Controls
Network Message Chart
Module Network Input MessagesRBM
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
Driver door ajar status | BCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current driver door status: AJAR, CLOSED. |
Left rear door ajar status | BCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current left rear door status: AJAR, CLOSED. |
Passenger door ajar status | BCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current passenger door status: AJAR, CLOSED. |
Right rear door ajar status | BCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current right rear door status: AJAR, CLOSED. |
Vehicle speed | PCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current vehicle speed. |
Power running board request status | IPC | This message is sent to the GWM and then to the RBM . This message informs the RBM of the requested PRB mode: AUTO, OUT, OFF. |
Ignition status | BCM | This message is sent to the GWM and then to the RBM . This message informs the RBM of the current ignition switch position. |
PRB System
The RBM module is located behind the rear passenger seat back. It is powered by BJB fuse F89 (40A) and grounded at G200. The RBM receives vehicle occupant input for the desired mode via MS-CAN from the IPC . The different modes are as follows:
The RBM controls the PRB position depending on occupant input as well as vehicle information data for automatic control. The RBM sets Continuous Memory Diagnostic Trouble Codes (DTCs) to aid in system diagnostics.
The PRB system will reverse PRB direction if there is an object interfering with movement or if there is excessive resistance due to debris or corrosion.
Component Description
PRB
The Power Running Boards (PRBs) are attached to the vehicle body with 2 PRB hinges with the front PRB hinge having the PRB motor attached. The front PRB hinge and PRB motor are serviced as an assembly. There is a PRB connecting rod between the front and rear PRB hinge that makes the PRB move evenly and smooth during operation. There are also 2 end caps on each PRB . The PRB torsion bars and end caps are serviced individually.
RBM
The RBM determines the need to move the LH or RH PRB and applies voltage and ground on only 2 circuits to the PRB motor in order to stow (retract) or deploy (extend) the PRB . To stow the PRB , the RBM applies voltage on the RB STOW circuit and ground on the RB DEPLOY circuit. To deploy the PRB the RBM switches the voltage and ground so the voltage is applied to the RB DEPLOY circuit and ground to the RB STOW circuit. The RBM monitors the movement and position of PRB with a hall-effect switch that is part of the PRB motor. The RBM supplies a 10 volt controlled voltage and a ground circuit to the PRB motor hall-effect sensor and receives a sensor signal from the hall-effect sensor.
PRB Motor
The PRB motor is a reversible motor that incorporates an internal hall-effect sensor for monitoring the position and movement of the PRB . The PRB motor is serviced as an assembly with the front PRB hinge.
Symptom Chart(s)
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
Symptom Chart - Differential
Symptom Chart - Differential