how to troubleshoot my Toyota Highlander Fourth Generation (2020-present) if it won’t unlock with th...

Toyota Highlander Fourth Generation (2020-present)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

575 words

Problem Statement

Learn how to troubleshoot and fix your Toyota Highlander key fob not unlocking the doors. Step-by-step guide with diagnostic steps and solutions.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Ensure the vehicle is in a secure location while testing the key fob functions to prevent accidental locking.

Symptoms

•Remote key fob does not unlock the doors
•Indicator lights on the fob do not illuminate when buttons are pressed
•Vehicle unlocks manually but not with the remote
•Repeated attempts to unlock with the fob yield no response
•Other remote functions, such as panic alarm, may also be non-functional

Diagnostic Steps

1
Check the battery level of the key fob by replacing it with a new battery.
2
Verify the fob is properly programmed to the vehicle using the owner's manual instructions.
3
Inspect the remote fob for physical damage or water intrusion.
4
Attempt to unlock the vehicle using a different key fob, if available.
5
Check the vehicle's battery voltage to ensure it is sufficient to power the locking system.
6
Scan the vehicle's Body Control Module (BCM) for any diagnostic trouble codes (DTCs) related to the keyless entry system.

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

•Small flathead screwdriver or coin
•Multimeter
•OBD-II scanner

Parts Required

•Key fob battery (CR2032 or equivalent)
•Replacement key fob (if necessary)

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Symptoms

•Remote key fob does not unlock the doors

•Indicator lights on the fob do not illuminate when buttons are pressed

•Vehicle unlocks manually but not with the remote

•Repeated attempts to unlock with the fob yield no response

•Other remote functions, such as panic alarm, may also be non-functional

Diagnostic Steps

1
Check the battery level of the key fob by replacing it with a new battery.
2
Verify the fob is properly programmed to the vehicle using the owner's manual instructions.
3
Inspect the remote fob for physical damage or water intrusion.
4
Attempt to unlock the vehicle using a different key fob, if available.
5
Check the vehicle's battery voltage to ensure it is sufficient to power the locking system.
6
Scan the vehicle's Body Control Module (BCM) for any diagnostic trouble codes (DTCs) related to the keyless entry system.

Solution

1. Battery Replacement

Remove the key fob cover using a small flathead screwdriver or a coin.
Extract the old battery (CR2032 or similar) and replace it with a new one, ensuring correct polarity.
Reassemble the key fob and test the unlocking function.

2. Reprogramming the Key Fob

Sit in the vehicle with all doors closed.
Insert the key into the ignition and turn it to the "ON" position without starting the engine.
Press the "LOCK" button on the key fob within 5 seconds.
Turn the ignition key to "OFF" and then back to "ON" to complete the programming process.
Test the fob to confirm functionality.

3. Inspecting the Key Fob

Visually examine the fob for cracks or signs of damage.
Open the fob and check for any corrosion or moisture inside.
If damage is found, consider replacing the key fob.

4. Testing with Another Key Fob

If available, test a different key fob to see if it unlocks the vehicle.
If the second fob works, the original key fob may need replacement.

5. Checking Vehicle Battery

Open the hood and use a multimeter to check the voltage of the vehicle battery; it should read between 12.4V to 12.7V for a fully charged battery.
If the battery is low, charge or replace it as necessary.

6. Scanning for DTCs

Use an OBD-II scanner to check for any trouble codes related to the BCM or keyless entry system.
Address any codes found according to manufacturer specifications.