SCP Bus Communication Failure U1173

The U1173 code indicates a communication failure on the SCP (Standard Corporate Protocol) network, which uses the SAE J1850 PWM physical protocol. This code is triggered when a control module receives invalid data or no data at all from the door panel or center console module responsible for managing remote control buttons (such as window, mirror, or memory function controls). This error is very common in Ford, Lincoln, and Mercury vehicles, where the network architecture relies on the J1850 bus to interconnect secondary modules with the main control module (PCM) or network interface module. Signal loss can be due to physical disconnection, a short circuit on the communication bus, or an internal failure in the transmitting module.