E 450 V8-5.4L (2009)
Trailer Brake Control Module: Pinpoint Tests
Pinpoint Test A: DTC B1863
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Pinpoint Tests
Pinpoint Test A: DTC B1863
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. See: Diagrams/Electrical Diagrams/Diagrams By
Number
Normal Operation
When a trailer is connected to the vehicle through the 7-pin trailer connector, the Trailer Brake Control (TBC) module will utilize the trailer as a
secondary ground. When the brake pedal is applied, the TBC module will send a Pulse Width Modulated (PWM) voltage to the brake solenoids on the
trailer to activate the trailer brakes. Releasing the brake pedal creates a feed-back voltage spike that is monitored by the TBC module. Normally, this
voltage travels through a diode inside the module and is grounded into the vehicle along circuit GD116 (BK/VT). However, if a condition should occur
that prevents the voltage from grounding along circuit GD116 (BK/VT), this feed-back voltage will create a voltage potential in the TBC module, this
voltage potential is detected by the module and, if the potential is greater than 19 volts, DTC B1863 will be set.
When DTC B1863 is set, the TBC module will disable trailer braking in order to protect the module from additional voltage spikes and the module will
also send a TBC FAULT message to the message center.
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B1863 TBC Ground Open Circuit - An open circuit condition in GD116 (BK/VT) or an internal failure of the TBC module will cause DTC B1863
to set. Unlike the other TBC module DTCs, a trailer must be connected to the 7-pin trailer connector for DTC B1863 to set during an on-demand
self test.
This pinpoint test is intended to diagnose the following:
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Wiring, terminals or connectors
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TBC module
PINPOINT TEST A: DTC B1863
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
NOTE: A trailer must be connected to the 7-pin trailer connector for DTC B1863 to set during the on-demand self test.
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A1 CHECK THE TBC MODULE GROUND CIRCUIT FOR AN OPEN
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Ignition OFF.
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Disconnect: TBC Module C2142.
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Measure the resistance between TBC module C2142-11, circuit GD116 (BK/VT), harness side and ground.
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Is the resistance less than 5 ohms?
Yes
GO to A2.
No
