my Tesla Model S Plaid/Refresh (2021-present) shows C1234 code, what does it mean?

Learn how to diagnose and fix C1234 brake issue in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, basic hand tools.
• Safety Warnings: Ensure the vehicle is on a level surface and in “Park” mode before starting any repairs.

2. Inspect and Replace Wheel Speed Sensors (if necessary)

1. Raise the Vehicle: Safely lift the vehicle using a jack and secure with jack stands.
2. Remove Wheel: Use a socket set to remove the wheel covering the affected brake assembly.
3. Disconnect Sensor: Locate the wheel speed sensor, disconnect the wiring harness carefully.
4. Unbolt Sensor: Use the appropriate socket to remove the sensor from its mounting bracket.
5. Install New Sensor: Position the new wheel speed sensor and secure it with bolts. Reconnect the wiring harness.
6. Reassemble Wheel: Reinstall the wheel and lower the vehicle back to the ground.

3. Check and Top Off Brake Fluid

1. Locate Brake Fluid Reservoir: Open the hood and find the brake fluid reservoir.
2. Inspect Fluid Level: Check the fluid level against the markings on the reservoir.
3. Add Fluid: If necessary, add the appropriate brake fluid (DOT 3 or as specified by Tesla) to the required level.
4. Close Reservoir Cap: Ensure the cap is securely fastened after checking.

4. Run Brake System Calibration

1. Connect to Service Tool: Use the Tesla service tool to access the brake calibration function.
2. Follow On-Screen Instructions: Execute the calibration procedure as prompted by the service tool.
3. Disconnect Tool: Once calibration is complete, disconnect the service tool from the vehicle.