F 150 4WD V8-4.6L VIN 8 (2010)
Trailer Brake Control Module: Initial Inspection and Diagnostic Overview
Special Tools Used With Diagnostics
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Principles of Operation
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Principles of Operation
The Trailer Brake Control (TBC) module is an integrated electronic control device that is designed to provide variable braking power to the
electric-actuated drum brakes on a towed trailer (1 to 4 axles only). The braking energy that is provided to the trailer is varied with a Pulse Width
Modulated (PWM) voltage that switches between 0 volt and battery voltage, the higher the duty cycle the more braking power available.
The TBC module receives information from 2 different brake pedal inputs: a Brake Pedal Position (BPP) switch (also known as the stoplamp switch) and
a brake pressure transducer. The BPP switch provides the PCM with current brake pedal position. This information is sent to the PCM as a voltage input
and is then transmitted to the TBC module over the High Speed Controller Area Network (HS-CAN) bus. The brake pressure transducer provides a
signal to the ABS module that varies with the force applied to the brake pedal. This information is also transmitted to the TBC module over the HS-CAN
bus.
The TBC module also receives additional vehicle information over the HS-CAN bus. These inputs are from the PCM, the Instrument Cluster (IC) and
the ABS module. These inputs are then used to determine the amount of braking power required for the trailer. The TBC module will also transmit
information to the ABS module and the IC in regards to trailer connectivity and current TBC system status. System status information that is sent to the
IC will be displayed in the IC message center to alert the driver of any potential concerns.
TBC module output to the trailer can be adjusted by the driver through the use of the manual slide lever and the 2 gain buttons. Pressing a gain button
with a trailer connected to the vehicle will adjust the TBC output to the trailer brakes to set the maximum assistance while making sure the trailer wheels
do not lock while braking. The maximum setting is 10.0 and the minimum setting is 0.0. The manual control lever is used to manually apply the trailer
brakes, independent of the vehicle brakes, in order to calibrate the trailer gain setting to the specific trailer loading and road conditions. For information
on setting trailer gain, refer to the Owner's Literature.
