Dtc C1203/59 Ecm Communication Circuit Malfunction
Check that the part number of the installed ECM is correct.
The skid control ECU detects if the brake pedal is depressed or not via this circuit.
The yaw rate sensor has a built in acceleration sensor and detects the vehicle's condition using 2 circuits (GL1, GL2).
The skid control ECU has an open detection circuit, which outputs this DTC when detecting an open in the stop light input line while the stop light switch is OFF.