What it means
The ABS module detects a fault associated with the left rear tone wheel used to generate wheel speed information. It sets the code when the wheel speed signal pattern is missing or inconsistent with expected rotation.
How it works
The left-rear tone wheel or encoder creates the pattern read by the left-rear wheel-speed sensor. The ABS module compares that signal with expected wheel rotation and sets this code when the left-rear pattern is missing or inconsistent, though the sensor or wiring may be responsible.
Common causes
Most likely first.
- Damaged or cracked tone wheel
- Rust or debris affecting the tone wheel
- Incorrect wheel bearing installation
- Excessive sensor-to-wheel gap
- Wheel speed sensor or wiring fault
Symptoms
- ABS warning light
- Traction control warning
- Stability control warning
- ABS may not operate correctly
How to diagnose it
- Read ABS-module codes and freeze-frame data, focusing on the left-rear wheel-speed value and any related sensor faults.
- Compare live left-rear speed with the other wheels during slow rotation to locate dropouts or an uneven signal.
- Inspect the left-rear tone wheel or encoder for cracks, rust, debris, looseness, or damage.
- Check left-rear sensor seating and gap, including whether recent bearing or hub work could have affected alignment.
- Inspect the left-rear sensor connector and harness for corrosion, damage, or snagging near the suspension.
- Test the left-rear sensor output and wiring using the manufacturer's procedure before considering the ABS module.
Common fixes
- Clean rust or debris from the left-rear tone-wheel area.
- Repair damaged or corroded left-rear sensor wiring or connector contacts.
- Correct the left-rear sensor position or gap according to the manufacturer's procedure.
- Replace the damaged left-rear tone wheel or encoder, including its integrated bearing assembly if applicable.
- Replace the left-rear sensor if testing confirms it is not reading the target correctly.
Can I keep driving?
ABS, traction control, or stability control may be limited, while basic braking can remain available. Drive carefully with extra stopping distance and avoid slippery roads until the left-rear signal is reliable.
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.