C1128moderate severityChassis
Rear Left ABS Sensor Signal Abnormal
on 2020 Subaru Legacy 2.5L H4 · AWD
What this code means
The ABS module is receiving an erratic signal from the rear left wheel speed sensor. Similar to OBD code C0045. Commonly due to a dirty tone ring or a weakening sensor.
Symptoms
- ABS light illuminated
- Traction control disabled
- Erratic wheel speed readings
Common causes
- Faulty rear left wheel speed sensor
- Dirty or damaged tone ring
- Damaged sensor wiring
- Excessive wheel bearing clearance
Diagnostic steps
- Scan for ABS trouble codes
- Inspect rear left sensor and harness
- Clean and check tone ring
- Scope the sensor signal while turning wheel
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Other Chassis codes on this vehicle
C0021
LF Wheel Speed Sensor Range/Performance
C0022
RF Wheel Speed Sensor Range/Performance
C0023
LR Wheel Speed Sensor Range/Performance
C0024
RR Wheel Speed Sensor Range/Performance
C0025
LF Wheel Speed Sensor Circuit Intermittent
C0026
RF Wheel Speed Sensor Circuit Intermittent
C0027
LR Wheel Speed Sensor Circuit Intermittent
C0028
RR Wheel Speed Sensor Circuit Intermittent
C0035
Left Front Wheel Speed Sensor Circuit
C0036
Left Front Wheel Speed Signal Erratic