C0518 code meaning
Left Front Wheel Speed Sensor - Mechanical
What C0518 means
C0518 points to a mechanical rather than electrical problem at the left front speed sensor: wrong part, wrong position, a damaged or soiled encoder, or play in the hub. No manufacturer documents this exact code publicly; GM's tables and Mitsubishi's index file such faults under range or correlation codes instead. The mechanics are well described elsewhere. GM bulletin PIT5950 for Silverado and Sierra 1500 warns that left and right front sensors look alike, that a swapped part keeps setting codes, and that the flat side of the tip must face the magnetic encoder ring on the wheel bearing. An Infiniti bulletin asks technicians to check the sensor head and the encoder for dirt, cracks, missing teeth, corrosion and looseness, since contamination alone can cause intermittent faults.
C0518 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of C0518
- ABS and stability lamps on, often recurring after a repair
- Uneven or missing left front speed reading at low speed
Common causes of C0518
- Most likelyMagnetic encoder or tone ring dirty, cracked or missing teeth
- PossibleSensor for the other side fitted or tip turned away from the encoder
- PossibleWorn or loose left front hub bearing changing the air gap
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Wss lfTone ring lf
What each part of C0518 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 18 | The exact fault in that area. |
What to do next
- Note C0518 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 C0518
What does C0518 mean?
C0518 means "Left Front Wheel Speed Sensor - Mechanical". C0518 points to a mechanical rather than electrical problem at the left front speed sensor: wrong part, wrong position, a damaged or soiled encoder, or play in the hub. It is a generic code, so it means the same on every make.
Is it safe to drive with C0518?
Drive gently and only to a workshop. With C0518 the car can go into limp mode (reduced power) to protect itself.
Will C0518 fail an emissions test?
C0518 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 C0518 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0518 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.