E 450 V8-5.4L (2009)
B6 CHECK FOR CORRECT TBC MODULE OPERATION
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Check the TBC module 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: TBC Module C2142.
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Make sure the connector is seated correctly, then 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. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the
self-test.
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Pinpoint Test C: The Message Center Displays Trailer Fault
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Pinpoint Tests
Pinpoint Test C: The Message Center Displays TRAILER FAULT
NOTE: Carry out all pinpoint tests without a trailer connected to the vehicle. See:
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 pin 3 of trailer tow connector C4099 along
circuit CAT19 (BU).
When there is no input from the stoplamp switch or manual slider lever, the TBC module continually sends a low voltage (approximately 0.3 volt) along
circuit CAT19 (BU) to pin-3 of the 7-pin trailer tow connector. Then, once every 4 seconds, this voltage is momentarily increased (approximately 0.5
volt) to determine whether or not a trailer is connected.
The factory 7-pin trailer tow connector is attached with a bracket to the rear bumper of the vehicle or to the trailer hitch (if equipped). The 7-pin trailer
tow connector acts as a jumper connection between C4099 (female) and the trailer electrical connector (female).
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DTC C2806 (Trailer Brakes Wiring Circuit Short to Voltage) If the TBC module output along circuit CAT19 (BU) is equal to or greater than 9
volts while not braking for 200 ms or more, the TBC module sends the TRAILER FAULT message to the Instrument Cluster (IC), shuts off trailer
brake output and then shuts down.
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DTC C2807 (Trailer Brakes Wiring Circuit Short to Ground) If battery voltage drops by more than 20% for 200 ms or more during a braking
event, or for 1.5 ms or more during an on-demand self test, the TBC module sends the TRAILER FAULT message to the IC, shuts off trailer brake
output and then shuts down. This DTC can also be set if the trailer brakes draw more than 28 amps for 20 ms or more.
This pinpoint test is intended to diagnose the following:
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Wiring, terminals or connectors
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TBC module
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Customer trailer
PINPOINT TEST C: THE MESSAGE CENTER DISPLAYS TRAILER FAULT
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
