C0502 code meaning
Left Front Wheel Speed Sensor A Circuit Low
Chassis system Generic code C05xx codes Check engine light
What C0502 means
C0502 reports the left front sensor circuit below its valid level, mostly a grounded wire or a supply that has sagged. In GM's 2019 tables (19OBDG03D) the brake module's Polaris ASIC sets C0502 for three conditions: the low side shorted to ground, tested only at power-up or after clearing codes (100 ms); sensor undervoltage (20 ms); and, unusually, an open sensor drawing under 3.5 mA, which other GM tables file as C0500. All are Type A. Audi bulletin 2061331/1 for 2017–2021 A4, A5, S and RS models stores C050200 as short to ground: a wire was poorly crimped in the front sensor connector, and the remedy is a new speed sensor and pad-wear harness. Mitsubishi's C1061-11 covers short and open circuits and even lights the parking brake warning.
C0502 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0502
- ABS and ESC lamps on right after starting
- Parking brake warning or electric parking brake functions restricted on some models
Common causes of C0502
- Most likelySensor wire chafed through to ground or poorly crimped in the connector
- PossibleSensor supply voltage too low (battery, fuse or module output)
- Less likelyInternal short in the left front sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Wss lfSensor wiring
What each part of C0502 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 02 | The exact fault in that area. |
What to do next
- Note C0502 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0502
What does C0502 mean?
C0502 means "Left Front Wheel Speed Sensor A Circuit Low". C0502 reports the left front sensor circuit below its valid level, mostly a grounded wire or a supply that has sagged. It is a generic code, so it means the same on every make.
Is it safe to drive with C0502?
Drive gently and only to a workshop. With C0502 the car can go into limp mode (reduced power) to protect itself.
Will C0502 fail an emissions test?
C0502 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0502 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0502 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.