What does code C0040 mean?

Q: What does code C0040 mean?

Left Rear Wheel Speed Sensor Circuit. C0040 means the antilock brake system (ABS) module has detected an abnormal signal from the left rear wheel speed sensor circuit, which can include an open circuit, short to ground or power, or an erratic signal. The computer compares that signal with the other three wheel speed sensors and sets this code when the left rear reading is missing, implausible, or inconsistent.

DTC codes / C00xx · Brakes, steering and suspension / C0040

C0040Left Rear Wheel Speed Sensor Circuit

C0040 means the antilock brake system (ABS) module has detected an abnormal signal from the left rear wheel speed sensor circuit, which can include an open circuit, short to ground or power, or an erratic signal. The computer compares that signal with the other three wheel speed sensors and sets this code when the left rear reading is missing, implausible, or inconsistent.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.