What it means
This code identifies a subfault associated with the left-front wheel-speed sensor. The base code does not specify the electrical or signal failure; consult the failure subtype and vehicle diagnostics.
How it works
The left-front wheel-speed sensor detects rotation from the tone wheel and sends that information to the ABS module. This base code identifies a left-front sensor-related subfault, but does not say whether the sensor, its circuit, or the signal conditions failed; the accompanying subtype and ABS data are needed to narrow it down.
Common causes
Most likely first.
- Faulty wheel-speed sensor
- Damaged or corroded wiring or connector
- Tone wheel or sensor air-gap problem
Symptoms
- ABS warning light
- Traction-control or stability-control warning
- ABS or stability-control function may be limited
How to diagnose it
- Read the ABS module's complete code and subtype information, then review freeze-frame data for the left-front wheel-speed reading when the fault set.
- Compare live left-front wheel speed with the other three wheels during a slow, safe rotation to identify dropouts or an implausible signal.
- Inspect the left-front sensor body, mounting, connector, and nearby harness for damage, contamination, looseness, or chafing.
- Inspect the left-front tone wheel or encoder and check sensor seating and air gap for debris or a mechanical issue.
- Test the left-front sensor and its signal wiring using the manufacturer's procedure, including checks for an open, short, or intermittent connection.
- If the sensor and wiring pass, investigate the tone-wheel signal and ABS-module input before replacing parts.
Common fixes
- Clean and secure the left-front sensor connector.
- Repair chafed, broken, or corroded left-front sensor wiring.
- Correct sensor mounting or remove debris affecting the left-front sensor gap.
- Replace the left-front wheel-speed sensor if testing confirms failure.
- Repair or replace the left-front tone wheel or encoder if its signal surface is damaged.
Can I keep driving?
The car may still brake normally, but ABS and traction or stability control can be unavailable or reduced. Drive cautiously, allow more stopping distance, and avoid conditions where those systems are especially useful.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.