F 550 2WD Super Duty V10-6.8L (2009)
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Is the resistance less than 5 ohms?
Yes
GO to F9.
No
REPAIR circuit CAT19 (BU). CLEAR the DTCs. REPEAT the self-test.
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F9 CHECK FOR CORRECT TBC MODULE OPERATION
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Disconnect the TBC module connector.
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Check the connector for:
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corrosion.
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pushed-out pins.
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spread terminals.
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Connect the TBC module connector and make sure that it is seated correctly.
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Operate the system and verify the concern is still present.
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Is the concern still present?
Yes
INSTALL a new TBC module. REFER to Trailer Brake Control (TBC) Module See: Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. INSPECT the 7-pin trailer tow connector for evidence of water intrusion or corrosion. INSPECT the trailer
tow C4099 harness for evidence of chaffed wiring or improper wire repair. REPAIR wiring as necessary. CLEAR the DTCs. REPEAT the self-test.
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Pinpoint Test G: The Trailer Brakes Are Inoperative
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Pinpoint Tests
Pinpoint Test G: The Trailer Brakes are Inoperative
NOTE: Carry out all pinpoint tests without a trailer connected to the vehicle.
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. See: Diagrams/Electrical Diagrams/Diagrams By
Number
Normal Operation
The braking energy that is provided to the trailer is varied with a Pulse Width Modulated (PWM) signal along circuit CAT19 (BU) that switches between
0 volt and battery voltage, the higher the duty cycle the more braking power available. The Trailer Brake Control (TBC) module varies the PWM signal
based on various inputs such as the brake pressure transducer, the manual slider switch and the gain buttons. With the vehicle stationary and with the
manual slider switch fully to the left with a gain of 10, there should be greater than 10-12 volts supplied to trailer tow C4099-3 circuit CAT19 (BU).
The TBC module also receives information from the brake pressure switch (also called the speed control deactivation switch) and the Brake Pedal
Position (BPP) (stoplamp) switch from the PCM over the High Speed Controller Area Network (HS-CAN) bus. The TBC module also receives
information from the ABS module over the HS-CAN bus. If there is a problem in the ABS module that is preventing this information from being sent to
the TBC module, the TBC module will enter a limited operating mode. The TBC module receives fused battery voltage from Battery Junction Box
(BJB) fuse 5 (30A) along circuit SBB05 (GY/RD) and fused ignition voltage from Smart Junction Box (SJB) fuse 33 (10A) along circuit CBP33
