what does code C1201 mean on my Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, and cleaning supplies.
• Ensure the vehicle is parked on a level surface and the ignition is turned off.
• Disconnect the battery to prevent electrical shorts while working on the ABS system.

2. Inspect and Clean ABS Wheel Speed Sensors

• Locate the ABS wheel speed sensors at each wheel hub.
• Remove the sensor mounting bolts using a socket set and carefully pull the sensor from its housing.
• Clean the sensor tip and surrounding area with a non-corrosive cleaner to remove any dirt or debris.
• Reinstall the sensor and torque the mounting bolts to the manufacturer's specifications.

3. Check Wiring and Connectors

• Inspect the wiring harnesses leading to the ABS sensors for any signs of wear, fraying, or corrosion.
• Disconnect the connectors and use electrical contact cleaner to clean the terminals.
• Reconnect the connectors securely and ensure they are locked in place.

4. Test Wheel Speed Sensors

• With the multimeter, measure the resistance across the wheel speed sensor terminals.
• Compare the readings to the specifications provided in the vehicle's service manual.
• If any sensor is out of specification, replace it.

5. Check ABS Control Module

• Reconnect the battery and use the OBD-II scanner to clear the C1201 code.
• Start the vehicle and perform a test drive to monitor for any reoccurrence of the code.
• If the code returns, the ABS control module may need to be tested for proper operation or replaced.