why does my Tesla Model S Plaid/Refresh (2021-present) check engine light keep coming on?

Solution

1. Preparation

• Tools Required: OBD-II scanner, diagnostic software, multimeter.
• Ensure the vehicle is parked on a flat surface and turned off.
• Disconnect the high-voltage battery for safety if necessary.

2. Retrieve and Analyze Error Codes

• Connect the OBD-II scanner to the vehicle's diagnostic port.
• Power on the scanner and select the option to read diagnostic trouble codes.
• Make a note of all codes present and their definitions for further analysis.

3. Inspect and Repair Identified Issues

• For each DTC retrieved, follow the manufacturer's service procedures.
• Address wiring issues: Repair or replace any damaged wires or connectors.
• If the codes indicate a battery issue, check for electrolyte leakage or swelling.
  • If needed, replace the high-voltage battery or its components.

4. Software Update

• Connect the vehicle to a Wi-Fi network.
• Check for any available software updates through the Tesla app or vehicle settings.
• Install updates as prompted to ensure optimal performance and bug fixes.

5. Reconnect Battery and Test

• Reconnect the high-voltage battery if it was disconnected.
• Start the vehicle and verify all systems are functioning properly.
• Conduct a test drive to ensure the check engine light does not reappear.