what does code C1231 indicate in my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, wire strippers, and electrical cleaner.
• Ensure the vehicle is on a flat surface and safely secured with wheel chocks.

2. Inspect the Wheel Speed Sensor

• Sub-step 1: Disconnect the front left wheel speed sensor connector.
• Sub-step 2: Inspect the wiring harness for any fraying or damage. Repair as necessary using wire strippers and soldering if needed.
• Sub-step 3: Clean the connector pins with electrical cleaner to remove any corrosion.

3. Test the Wheel Speed Sensor

• Sub-step 1: Connect the multimeter to the two terminals of the front left wheel speed sensor.
• Sub-step 2: Spin the wheel and check for a voltage signal. Ensure it falls within the manufacturer’s specified range (usually around 0.5 to 1.5 volts AC).
• Sub-step 3: If the voltage is outside of the specified range, replace the wheel speed sensor.

4. Replace the Wheel Speed Sensor (if necessary)

• Sub-step 1: Remove the wheel and brake caliper for access to the wheel speed sensor.
• Sub-step 2: Remove the old wheel speed sensor by unscrewing it from its mounting bracket.
• Sub-step 3: Install the new wheel speed sensor, ensuring it is secured to the correct torque specifications (typically around 7-10 ft-lbs).
• Sub-step 4: Reattach the brake caliper and wheel.

5. Reset the ABS System

• Sub-step 1: Reconnect the OBD-II scanner and clear the C1231 code.
• Sub-step 2: Test drive the vehicle to ensure the ABS warning light does not reappear.