U1040 GMC - SCP Invalid or Missing Data for Vehicle Speed
- 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)
Tech notesThis is typically an electrical wiring connection issue, either at the engine controller or at the sensors being monitored by the manufacturer.
It can occur if:
Wiring to the vehicle speed sensor breaks or the sensor itself has issues.
When is the code detected?When the PCM is unable to communicate with any other controller on the bus network at any time while the ignition switch is in the “Run” position.
- Engine Light ON (or Service Engine Soon Warning Light)
- O/D Light Flashes Continuously
- Speedometer does not register
U1040 Gmc DescriptionThis 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.
Need more help?Get the U1040 Gmc code diagnosed by a professional: Find a repair shop in your area
U1040 GMC CommentsHelp us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the U1040 Gmc code? Have you replaced any parts?
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