how to fix Tesla Model 3 Original (2017-2023) that won't unlock

Tesla Model 3 Highland (2024-present)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

502 words

Problem Statement

Learn how to diagnose and fix unlocking issues in Tesla Model 3 (2017-2023). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the vehicle's 12V battery before performing any electrical work to avoid shocks or short circuits.

Symptoms

•Key fob not responding to unlock commands
•Mobile app not able to unlock the vehicle
•Physical door handles not extending
•No response from the vehicle when attempting to unlock
•Dashboard displays 'Key not detected' message

Diagnostic Steps

1
Verify the battery level of the key fob using the Tesla app.
2
Check for software updates in the Tesla mobile app or vehicle display.
3
Inspect the key fob for physical damage or water exposure.
4
Test the key fob by holding it against the B-pillar to see if the car responds.
5
Check the vehicle’s 12V battery voltage using a multimeter.
6
Inspect for any blown fuses related to the unlocking mechanism.

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
•Fuse puller
•Small flathead screwdriver
•Socket set

Parts Required

•Key fob battery (CR2032)
•12V battery (if required)

Related Faults

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Diagnostic Steps

1
Verify the battery level of the key fob using the Tesla app.
2
Check for software updates in the Tesla mobile app or vehicle display.
3
Inspect the key fob for physical damage or water exposure.
4
Test the key fob by holding it against the B-pillar to see if the car responds.
5
Check the vehicle’s 12V battery voltage using a multimeter.
6
Inspect for any blown fuses related to the unlocking mechanism.

Solution

1. Preparation

Tools Required: OBD-II scanner, multimeter, fuse puller.
Ensure the vehicle is in a safe and accessible location, preferably outdoors.
Disconnect the vehicle’s 12V battery to avoid any electrical issues during repair.

2. Replace Key Fob Battery

Sub-steps:
1. Open the key fob using a small flathead screwdriver to pry it apart gently.
2. Remove the old battery (usually a CR2032) and replace it with a new one, ensuring correct polarity.
3. Snap the key fob back together securely.

3. Check and Replace 12V Battery

Sub-steps:
1. Access the 12V battery located in the front trunk (frunk).
2. Using a multimeter, check the voltage; it should be around 12.6 volts when fully charged.
3. If below 12V, remove the old battery using a socket set and replace it with a new, compatible 12V battery.
4. Reconnect the battery terminals, ensuring they are tight.

4. Reset Key Fob

Sub-steps:
1. With the vehicle powered on, press the brake pedal and place the key fob against the B-pillar.
2. Use the touchscreen to navigate to “Controls” and then “Key Fob.”
3. Select “Remove Key Fob” if it is displayed, then confirm.
4. Follow the prompts to re-add the key fob.