Pinpoint Test B: The Trailer Brakes Are Inoperative
WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
NOTE:
Make sure the trailer brakes are electric-magnet actuated drum-type brakes before proceeding with this pinpoint test.
- B1 CHECK FOR ANY PCM DTCs
- Ignition ON.
- Allow at least 10 seconds for all modules to wake up and prove out.
- Enter the following diagnostic mode on the scan tool: Self Test - PCM Key ON Engine OFF (KOEO).
- Retrieve and record any PCM DTCs.
Are any PCM DTCs retrieved?
- Yes : REFER to ELECTRONIC ENGINE CONTROLS .
- No : GO to B2 .
- B2 CHECK FOR ANY ABS MODULE DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Retrieve and record any ABS module DTCs.
Are any ABS module DTCs retrieved?
- Yes : REFER to ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL .
- No : GO to B3 .
- B3 CHECK FOR SCAN TOOL COMMUNICATION WITH THE TBC MODULE
- Using a scan tool, carry out the network test.
Did the TBC module pass the network test?
- Yes : GO to B4 .
- No : REFER to MODULE COMMUNICATIONS NETWORK .
- B4 CHECK FOR TBC MODULE DTCs
- Review the DTCs retrieved and recorded during TBC module self-test.
Are any TBC module DTCs present?
- Yes : REFER to the TRAILER BRAKE CONTROL (TBC) MODULE DTC CHART .
- No : GO to B5 .
- B5 CHECK THE TBC MODULE FOR MAXIMUM OUTPUT NOTE: Battery voltage must be greater than 10 volts.
- Ignition ON.
- Set a gain of 10 in the TBC module.
-
NOTE: If the manual slider switch is held to the full left position for more than 5 to 20 minutes, the TBC module automatically shuts down.
Have an assistant press the manual slider switch fully to the left with a gain of 10 on the TBC module.
- Measure the voltage between trailer tow 7-pin trailer tow connector electric brake supply pin, component side and ground.
Is the voltage greater than 10-12 volts?
- Yes : The TBC module is operating correctly. SEND the trailer to an authorized camper/trailer repair center for an overload condition.
- No : GO to B6 .
- B6 CHECK THE TRAILER TOW CONNECTOR FOR AN OPEN
- Ignition OFF.
- Disconnect: Trailer Tow Connector C439A .
- Ignition ON.
- Have an assistant press the manual slider switch fully to the left with a gain of 10 on the TBC module.
- Measure the voltage between the trailer tow connector C439A-3 , circuit CAT19 (BU), harness side and ground.
Is the voltage greater than 10 volts?
- Yes : INSTALL a new trailer tow connector. CLEAR the DTCs. TEST the system for normal operation.
- No : GO to B7 .
- B7 CHECK THE TBC MODULE PWM OUTPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the trailer tow connector C439A-3 , circuit CAT19 (BU), harness side and TBC module C2142-14 , circuit CAT19 (BU), harness side.
Is the resistance less than 5 ohms?
- Yes : GO to B8 .
- No : REPAIR the circuit. TEST the system for normal operation.
- B8 CHECK THE BATTERY VOLTAGE TO THE TBC MODULE
- Ignition OFF.
- Measure the voltage between TBC module C2142-8 , circuit SBB17 (RD), harness side and ground.
Is the voltage greater than 10 volts?
- Yes : GO to B9 .
- No : VERIFY the BJB fuse 17 (30A) is OK. If OK, REPAIR circuit SBB17 (RD) for an open. TEST the system for normal operation.
- B9 CHECK FOR CORRECT TBC MODULE OPERATION
- Disconnect the TBC module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the TBC module connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
- Yes : INSTALL a new TBC module. REFER to TRAILER BRAKE CONTROL (TBC) MODULE . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.