C0045 — Left Rear Wheel Speed Sensor Circuit

What it means

C0045 is a generic Chassis/ABS code indicating a fault in the left-rear (LR) wheel speed sensor circuit. Typical set conditions include an open/short in the LR sensor wiring, a missing/erratic signal, or a failed sensor; some platforms also implicate the hub/encoder or, less commonly, the ABS module input channel. CarParts

Symptoms

  • ABS warning light on; traction/stability control disabled or limited.
  • Possible messages like “Service Stabilitrak/ESC.”
  • In some vehicles, speedometer or cruise issues; low-speed ABS pulsation if the signal is noisy/intermittent. Chevy Malibu Forum

Severity / priority

High (safety-related). Foundation brakes still function, but ABS/ESC capability is reduced or disabled, which can increase stopping distance and reduce stability on low-traction surfaces. Address promptly. CarParts

Common causes

  • Failed LR wheel speed sensor (internal open/short; contamination).
  • Harness/connector faults at the knuckle or intermediate junction (chafe, water intrusion, corrosion).
  • Damaged/misaligned tone ring or encoder bearing (integrated in many hubs).
  • Less common: ABS module input fault. CarParts

Diagnostic notes

  • Use a scan tool with live wheel-speed data; compare LR vs. the other three sensors during a steady roll.
  • Inspect the LR sensor seating/air gap, debris on the tip, and the short pigtail to the first connector (common failure point).
  • For active (digital) sensors, verify supply and ground; for passive (inductive), scope the AC waveform.
  • If the vehicle uses an encoder hub, check for rust jacking, cracks, or missing segments; replace the hub if the encoder is compromised. CarParts

Possible fixes

  • Clean/reseat or replace the LR wheel speed sensor; set air gap per spec.
  • Repair/replace damaged wiring or connectors; restore insulation and routing.
  • Replace the hub/bearing if the encoder/tone ring is damaged.
  • If inputs/harness test good, evaluate the ABS module per service manual procedures. CarParts

Sources: CarParts technical overview of C0045 (definition, causes, symptoms, diagnostics); community/OEM-aligned threads noting encoder/harness issues and Stabilitrak messages. CarParts+2Chevy Malibu Forum+2