U1123 Code: Meaning, Causes, and Symptoms | OBD2 Codes

U1123 – SCP Invalid or Missing Data for Odometer


U1123 Possible Symptoms


Engine Light ON (or Service Engine Soon Warning Light),O/D Light Flashes Continuously,Speedometer does not register


U1123 Possible Causes


Faulty / intermittent vehicle speed sensor / connections,J1850 / SCP / CAN Bus wiring intermittently open, shorted to power or ground,Faulty / intermittent connection at the Powertrain Control Module (PCM),Faulty / intermittent connection at the Anti-Lock Brake Module (ABS)


U1123 Description


This is a manufacturer specific fault code and can be used for several different faults, depending upon what the manufacturer wants to use it for. Controllers communicate over the Serial Communication Protocol (SCP) bus network, also known as J1850 bus, or Controller Area Network or CAN Bus. These bus communication systems may or may not be fault tolerant, which means any type of intermittent/loose connection between these controllers could cause communication to stop. When these controllers are unable to communicate with each other at any time while the ignition switch is turned on, code U1123 will set.