OBD-II code · Chassis
C0503 Left Front Wheel Speed Sensor A Circuit High
Left-front wheel speed sensor A signal voltage above expected range. Wheel-speed signals feed ABS, ESC, traction control, transmission and odometer — a single dropped signal disables all of these safety functions until repaired.
Is it safe to drive with C0503?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySignal wire open or short to power
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Wss Lf, Sensor Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.