How do I address a malfunctioning keyless entry system in a 2021 Highlander?

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

644 words

Problem Statement

Learn how to diagnose and repair a malfunctioning keyless entry system in a 2021 Toyota Highlander with step-by-step instructions.

Affected Component

Keyless Entry System

Estimated Time

2-4 hours

Symptoms

•Key fob not responding
•Vehicle not recognizing the key fob
•Intermittent operation
•No response when approaching the vehicle

Diagnostic Steps

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

•Flathead screwdriver
•Phillips screwdriver
•Key fob battery (CR2032)
•OBD-II scanner
•Multimeter
•Torx or socket set
•Owner’s manual

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Solution

Addressing a Malfunctioning Keyless Entry System in a 2021 Toyota Highlander

Tools Required

Flathead and Phillips screwdrivers
Key fob battery (CR2032)
OBD-II scanner
Multimeter
Torx or socket set (for accessing the BCM if needed)
Owner’s manual for key fob reprogramming instructions

Repair Instructions

Replace the Key Fob Battery:
- Carefully open the key fob casing using a flathead screwdriver.
- Replace the old battery with a new CR2032 battery, ensuring proper polarity.
- Reassemble the fob and test the functionality.
Reprogram the Key Fob:
- Insert the key into the ignition and turn to the "ON" position.
- Press the "LOCK" button on the fob. If successful, you will hear the locks cycle.
- Turn the ignition off and test the key fob.
Inspect and Repair Wiring:
- If you identify damaged wiring or loose connectors, repair or replace them as necessary.
- Ensure all connections are secure, especially at the BCM and antenna.
Replace the BCM (if necessary):
- Disconnect the vehicle battery for safety.
- Remove the necessary panels to access the BCM.
- Disconnect all wiring harnesses from the BCM.
- Replace with a new or refurbished BCM.
- Reconnect the battery and have the new BCM programmed to the vehicle by a dealer.
Final Testing:
- After repairs, test the keyless entry system from various distances and angles to ensure proper operation.
- Check for any persistent error codes using the OBD-II scanner.

By following these steps, you should be able to effectively diagnose and repair a malfunctioning keyless entry system in a 2021 Toyota Highlander. If problems persist, it may be beneficial to consult a professional technician or the dealership.