ABS and Traction Control Lights On in 2022 Highlander Limited

ClearTheCode admin answer:

When both the ABS and Traction Control (TRAC OFF) lights illuminate, it typically indicates a fault within the vehicle's anti-lock braking system or a related sensor. Since these systems are interconnected, a problem in one often affects the other.

1. Common Causes for Both Lights On:

   • Wheel Speed Sensor Failure: This is the most frequent cause. Each wheel has a sensor that monitors its rotational speed. If a sensor is dirty, damaged, or has a wiring issue, the ABS/Traction Control module loses crucial data, triggering the lights. OBD-II codes like C0031 (Front Left Wheel Speed Sensor), C0032 (Front Right), C0033 (Rear Left), or C0034 (Rear Right) are common.
   • ABS Module Malfunction: Less common, but the ABS control module itself can fail. This is usually a more expensive repair.
   • Low Brake Fluid: While less likely to trigger both simultaneously without other symptoms, extremely low brake fluid can sometimes cause issues.
   • Faulty Wiring/Connectors: Corrosion or damage to the wiring harness leading to the wheel speed sensors or ABS module can interrupt signals.
   • Steering Angle Sensor: A fault in the steering angle sensor can also affect traction control and stability systems.
   • Recent Tire Work: If tires were recently replaced or rotated, an improperly seated sensor or damaged wiring could occur.

2. Initial Steps & Diagnostics:

   • Check Brake Fluid Level: Ensure your brake fluid reservoir is at the proper level.
   • Visual Inspection: Look around each wheel for any obvious damage to the wheel speed sensor wires or connectors. Heavy rain could potentially dislodge or short a connection if there's existing damage.
   • OBD-II Scan: The most crucial step is to get the vehicle scanned for diagnostic trouble codes (DTCs). Even if your check engine light isn't on, an advanced scanner can read ABS-specific codes that will pinpoint the exact issue.

3. When to See a Shop:

   • You should get your Highlander to a qualified mechanic or dealership as soon as possible. While the regular brakes may still function, the ABS and Traction Control systems are disabled, meaning you won't have their assistance in emergency braking or slippery conditions. A professional can accurately read the codes, diagnose the specific sensor or module fault, and perform the necessary repairs to restore these critical safety features.