System: Chassis (C-Code)
SAE Standard (Generic)
Family: Wheel Speed Sensor Circuit
Code C0031: Left Front Wheel Speed Sensor
Diagnostic & Technical Explanation
Code C0031 (Left Front Wheel Speed Sensor) sets when the ABS module loses a valid electrical signal from a wheel speed sensor -- the circuit reads open, shorted low or high, drops out intermittently, fails to correlate with the other three wheels, or reports an incorrect component installed. The diagnosis and repair are identical at every corner: a corroded or unplugged connector, a chafed harness conductor rubbing on the strut or subframe, or a failed Hall-effect/variable-reluctance sensor element. This is distinct from a tone-ring or mechanical fault, where the wiring and sensor test fine but the signal is noisy or absent because of physical damage at the reluctor wheel.
First-listed procedure
Rank #1
Inspect wheel speed sensor connector and harness routing
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 3 procedure(s) are in the licensed dataset. Ordering context.
Full family: Wheel Speed Sensor Circuit
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)