how to diagnose U0401 code on Tesla Model S Plaid/Refresh (2021-present)

• •Check engine light illuminated
• •Reduced power output or performance
• •Erratic behavior of electronic components (e.g., display issues)
• •Possible warnings on the dashboard related to powertrain or safety systems
• •Inconsistent vehicle response during acceleration or braking

1. 1Scan for error codes using an OBD-II scanner to confirm U0401 and check for any additional codes.
2. 2Inspect the vehicle's wiring harness and connectors associated with the powertrain control module for signs of damage or corrosion.
3. 3Verify the battery voltage and health, ensuring it is within the manufacturer's specifications.
4. 4Check the software version of the vehicle's firmware; ensure it is up to date.
5. 5Perform a visual inspection of the control modules for any physical damage or signs of overheating.
6. 6Use a diagnostic tool to monitor live data from the affected control modules to identify irregularities.

After completing the repair, verify that the issue has been resolved:

• ✓Test the affected component to ensure it functions correctly
• ✓Check for any error codes or warning lights
• ✓Monitor the vehicle for a few days to ensure the issue does not recur

To prevent this issue from occurring again:

• •Follow the manufacturer's recommended maintenance schedule
• •Address warning signs early before they develop into major issues
• •Use quality parts and fluids recommended for your vehicle
• •Keep detailed records of all repairs and maintenance

• •OBD-II scanner
• •Multimeter
• •Socket set
• •Torque wrench
• •Tesla diagnostic tool

• •Replacement control module (if diagnosed as faulty)
• •Wiring harness (if damaged)