how to fix U0140 code in Tesla Model 3 Original (2017-2023)

Tesla Model 3 Highland (2024-present)

Error Codes

1-3 hours

Time

medium

Difficulty

high

Severity

Error Code: U0140

3 min read

534 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix U0140 electrical communication issues in Tesla Model 3 (2017-2023). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

U0140

Affected Component

Electrical

Estimated Time

1-3 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the vehicle from any power source before working on electrical systems.

Symptoms

•Check engine light illuminated
•Inoperative electronic accessories (e.g., windows, locks)
•Loss of functionality in dashboard displays
•Unexpected battery drain
•Error messages on the vehicle’s interface

Diagnostic Steps

1
Scan the vehicle using an OBD-II scanner to confirm U0140 code and check for any additional codes.
2
Inspect the wiring harness and connectors associated with the BCM for damage, corrosion, or loose connections.
3
Verify the voltage and ground at the BCM using a multimeter to ensure proper power supply.
4
Check for software updates for the BCM and other related modules via Tesla service.
5
Perform a reset of the vehicle's systems by powering down and restarting the vehicle.
6
If possible, check the status of the CAN (Controller Area Network) bus for communication errors.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

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

Prevention Tips

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

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Basic hand tools (screwdrivers, socket set)

Parts Required

•Replacement wiring harness (if damaged)
•New connectors (if corrosion is found)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan the vehicle using an OBD-II scanner to confirm U0140 code and check for any additional codes.
2
Inspect the wiring harness and connectors associated with the BCM for damage, corrosion, or loose connections.
3
Verify the voltage and ground at the BCM using a multimeter to ensure proper power supply.
4
Check for software updates for the BCM and other related modules via Tesla service.
5
Perform a reset of the vehicle's systems by powering down and restarting the vehicle.
6
If possible, check the status of the CAN (Controller Area Network) bus for communication errors.

Solution

1. Preparation

Gather tools and safety equipment.
Tools Required: OBD-II scanner, multimeter, basic hand tools (screwdrivers, socket set).
Ensure the vehicle is parked on a level surface and in "Park" mode.

2. Inspect Wiring and Connections

Sub-steps:
1. Remove the cover panel to access the BCM (typically located under the dashboard).
2. Visually inspect the wiring harness for any signs of wear, fraying, or corrosion.
3. Disconnect and reconnect the connectors to ensure a secure fit.

3. Check Power and Ground

Sub-steps:
1. With the multimeter, check the voltage at the BCM connection; it should read between 12V and 14V.
2. Check the ground connection by measuring resistance to the vehicle chassis; it should be less than 5 ohms.
3. If the readings are out of spec, trace the wiring back to the power source to identify any faults.

4. Update Software

Sub-steps:
1. Connect to the Tesla service portal or app to check for software updates for the BCM.
2. Follow the prompts to update if an update is available.

5. Reset Vehicle Systems

Sub-steps:
1. Power down the vehicle completely by turning it off and waiting for a few minutes.
2. Restart the vehicle and observe if the U0140 code reappears.