Some 2021-2023 F-150 vehicles may exhibit DTCs B1D08 And/Or B1D09 stored in the trailer module (TRM) with a Trailer Brake System Fault See Manual message in the instrument panel cluster (IPC) when a trailer is not connected to the vehicle. This may be due to water intrusion at the back side of the trailer tow connector. Disconnect connector C4099 from the back of the trailer tow connector (14489). Inspect connector C4099 and the mating socket on the back of the trailer tow connector for signs of corrosion or damage. If corrosion or damage is present at either connector, replace both the female side of the C4099 connector using service pig tail kit (3U2Z-14S411-JXC) and the trailer tow connector. If corrosion or damage is not present, refer to the Workshop Manual (WSM) Section 417-01 Exterior Lighting, Diagnosis and Testing for additional diagnosis. For claiming, use causal part 13A576 and applicable labor operations in Section 01 of the Service Labor Time Standards (SLTS) Manual.
