Pinpoint Test As : The TBM (Trailer Brake Control Module) Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

AS1 CHECK THE TBM (TRAILER BRAKE CONTROL MODULE) VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect: TBM C2142 .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2142-8	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to AS2

No	VERIFY the BJB fuse 24 (30A) is OK. If OK, REPAIR the circuit. If not OK, Refer to the Wiring Diagram Information to identify the possible causes of the circuit short.

AS2 CHECK THE TBM (TRAILER BRAKE CONTROL MODULE) GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2142-3	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to AS3

No	REPAIR the circuit.

AS3 CHECK THE HS-CAN2 (HIGH-SPEED CONTROLLER AREA NETWORK 2) CIRCUITS BETWEEN THE TBM (TRAILER BRAKE CONTROL MODULE) AND THE DLC (DATA LINK CONNECTOR) FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2142-10	Courtesy of FORD MOTOR COMPANY	C251-3
C2142-11	Courtesy of FORD MOTOR COMPANY	C251-11

Are the resistances less than 3 ohms?

Yes

GO to AS4

No	REPAIR the circuit in question.

AS4 CHECK FOR CORRECT TBM (TRAILER BRAKE CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect the TBM connector.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the TBM connector. Make sure it seats and latches correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable service articles: TSB, General Service Bulletin (GSB), SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new TBM. REFER to: Trailer Brake Control Module (TBM) .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.