U1040 CHEVROLET – SCP Invalid or Missing Data for Vehicle Speed

U1040 CHEVROLET Possible Symptoms

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

U1040 CHEVROLET Possible Causes

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

U1040 CHEVROLET 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. The Powertrain Control Module (PCM) communicates over the Serial Communication Protocol (SCP) bus network, or J1850 bus. This is a medium-speed bus communication system and is fault tolerant, which means any type of intermittent/loose connection at these controllers will cause this code to set in memory, but will still operate, provided a data path is available. When the PCM is unable to communicate with any other controller at any time while the ignition switch is turned on, code U1040 will set. This is the typical reason for this code to set.