Symptom Chart: Trailer Brake System
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .
| Condition | Possible Sources | Actions |
|---|---|---|
| A module does not respond to the diagnostic scan tool | Fuse Wiring, terminals or connectors Communication network concern TBM |
REFER to: Communications Network . |
| The trailer brakes are inoperative | Refer to the Pinpoint Tests | GO to Pinpoint Test A |
| The trailer brakes are always engaged | Refer to the Pinpoint Tests | GO to Pinpoint Test B |
| The message center displays TRAILER BRAKE MODULE FAULT | Diagnostic Trouble Codes (DTCs) present in the TBM | RETRIEVE and RECORD the Diagnostic Trouble Codes (DTCs). GO to the DTC Chart: TBM |
| The message center displays TRAILER BRAKE MODULE FAULT when the vehicle is not equipped with a TBM | Incorrect IPC configuration | CONFIGURE the IPC car configuration parameters. REFER to: Module Configuration - System Operation and Component Description . |
| The message center displays TRAILER DISCONNECTED, TRAILER GAIN XX.XX, NO TRAILER after a trailer is connected to the vehicle and the manual slider switch is moved or a gain button is pressed. | The TBM requires a minimum of 5 seconds after a trailer is connected to "detect" the trailer. This learning process requires no input from the brake pedal, TBM manual slider switch or gain buttons. If the brake pedal is pressed, the manual slider switch is moved or a gain button is pressed, the learning process is stopped and the TBM cannot detect the trailer. | INFORM the customer of the learning process and they must wait at least 5 seconds after connecting a trailer before pressing the brake pedal, moving the manual slider switch or pressing the gain buttons. |
| The message center intermittently displays TRAILER DISCONNECTED or WIRING FAULT ON TRAILER while towing a trailer | Refer to the Pinpoint Tests | GO to Pinpoint Test C |
| The message center displays WIRING FAULT ON TRAILER | Refer to the Pinpoint Tests | GO to Pinpoint Test C |
| No power at 7 way power/charge wire | Fuse Wiring, terminals or connectors Communication network concern TRM |
REFER to: Trailer Lamps . |
| The message center displays TRAILER CONNECTED when no trailer is connected | Refer to the Pinpoint Tests | GO to Pinpoint Test D |
| The message center does not display a TRAILER CONNECTED message when a trailer is connected | Refer to the Pinpoint Tests | GO to Pinpoint Test D |