OBD-II code · Chassis
C0509 Right Front Wheel Speed Sensor A Circuit High
Right-front WSS 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 C0509?
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 Rf, Sensor Wiring
Related codes
- C065BRight Front Wheel Speed Sensor B Circuit High
- C0506Right Front Wheel Speed Sensor A Circuit/Open
- C0507Right Front Wheel Speed Sensor A Range/Performance
- C0508Right Front Wheel Speed Sensor A Circuit Low
- C050ARight Front Wheel Speed Sensor A Intermittent/Erratic
- C050BRight Front Wheel Speed Sensor A Correlation
- C050CLeft Rear Wheel Speed Sensor A Circuit/Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.