how to troubleshoot blind spot monitoring not working in Toyota Highlander Fourth Generation (2020-p...

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

578 words

Problem Statement

Learn how to troubleshoot and fix blind spot monitoring issues in the 2020-present Toyota Highlander. Step-by-step guide with diagnostic and repair instructions.

Affected Component

Electrical

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on any electrical system to avoid accidental shorts

Symptoms

•Blind spot monitoring warning lights not illuminating
•No audible alerts when vehicles are detected in blind spots
•Malfunction indicator lamp illuminated on the dashboard
•Inconsistent operation of the system (works intermittently)
•Decreased or no response from the blind spot monitoring system when changing lanes

Diagnostic Steps

1
Scan for error codes using OBD-II scanner
2
Inspect the blind spot sensors for dirt, debris, or damage
3
Check the wiring harness for wear, damage, or loose connections
4
Verify that the blind spot monitoring feature is enabled in the vehicle's settings menu
5
Perform a system reset by disconnecting and reconnecting the vehicle's battery
6
Test the vehicle's electrical system at the blind spot sensors using a multimeter

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
•Socket set
•Torque wrench
•Cleaning supplies (soft cloth and water)

Parts Required

•Blind spot monitoring sensor (if faulty)

Related Faults

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Symptoms

•Blind spot monitoring warning lights not illuminating

•No audible alerts when vehicles are detected in blind spots

•Malfunction indicator lamp illuminated on the dashboard

•Inconsistent operation of the system (works intermittently)

•Decreased or no response from the blind spot monitoring system when changing lanes

Diagnostic Steps

1
Scan for error codes using OBD-II scanner
2
Inspect the blind spot sensors for dirt, debris, or damage
3
Check the wiring harness for wear, damage, or loose connections
4
Verify that the blind spot monitoring feature is enabled in the vehicle's settings menu
5
Perform a system reset by disconnecting and reconnecting the vehicle's battery
6
Test the vehicle's electrical system at the blind spot sensors using a multimeter

Solution

1. Preparation

Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, cleaning supplies (like a soft cloth and water).
Safety Warnings: Disconnect the battery before working on any electrical system to avoid accidental shorts.

2. Inspect and Clean Sensors

Sub-steps:
1. Locate the blind spot monitoring sensors on the rear bumper.
2. Clean the sensor areas with a soft cloth to remove any dirt or debris that may obstruct the sensors.
3. Inspect for any physical damage to the sensors or bumper area; replace if necessary.

3. Check and Repair Wiring

Sub-steps:
1. Remove the rear bumper if necessary to access the wiring harness.
2. Inspect the wiring for any frays or breaks; repair or replace as needed.
3. Ensure all connectors are secure and free of corrosion.

4. Reset System

Sub-steps:
1. Disconnect the negative terminal of the battery and wait for at least 10 minutes.
2. Reconnect the battery terminal securely.
3. Start the vehicle and check if the blind spot monitoring system is functioning properly.

5. Replace Sensors (if necessary)

Sub-steps:
1. If the sensors are found to be faulty through testing, remove the damaged sensor using a socket set.
2. Install the new sensor, ensuring it is aligned properly.
3. Torque the mounting bolts to the manufacturer's specifications (typically around 5-10 Nm).
4. Reconnect any wiring harnesses to the new sensor.