what to do if my Toyota Highlander electric power steering stops working

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

critical

Severity

3 min read

561 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 electric power steering failure in Toyota Highlander. Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

Steering

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the vehicle to cool down if the engine has been running before servicing.

Symptoms

•Steering wheel feels heavy or unresponsive
•Warning light on the dashboard (EPS or power steering warning light)
•No assist when turning the wheel
•Increased effort required to maneuver the vehicle, especially at low speeds
•Noise coming from the steering column or motor area

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for any related trouble codes.
2
Inspect the EPS fuse for any blown fuses that could interrupt power to the system.
3
Check the wiring harness for any damaged or disconnected electrical connections related to the EPS motor.
4
Examine the EPS motor for any visible signs of wear, damage, or overheating.
5
Perform a voltage test on the EPS motor to ensure it is receiving adequate power.
6
Test the EPS control module for proper function and communication with the vehicle’s computer 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

•OBD-II scanner
•Multimeter
•Socket set
•Screwdriver set
•Torque wrench

Parts Required

•EPS fuse (if blown)
•EPS motor (if faulty)
•Wiring harness (if damaged)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for any related trouble codes.
2
Inspect the EPS fuse for any blown fuses that could interrupt power to the system.
3
Check the wiring harness for any damaged or disconnected electrical connections related to the EPS motor.
4
Examine the EPS motor for any visible signs of wear, damage, or overheating.
5
Perform a voltage test on the EPS motor to ensure it is receiving adequate power.
6
Test the EPS control module for proper function and communication with the vehicle’s computer system.

Solution

1. Preparation

Gather all necessary tools and parts.
Disconnect the battery negative terminal to prevent electrical shocks.
Ensure the vehicle is on a flat surface and securely supported.

2. Inspect and Replace the EPS Fuse

Locate the fuse box (refer to the owner's manual for exact location).
Remove the fuse related to the electric power steering.
Check if the fuse is blown. If it is, replace it with a new fuse of the same amperage.
Reconnect the battery and test the steering.

3. Repair Wiring Issues

Inspect the wiring harness connected to the EPS motor.
Look for any signs of fraying, corrosion, or disconnection.
If damaged, repair or replace the wiring harness as necessary.
Ensure all connections are secure and test the system again.

4. Replace the EPS Motor (if faulty)

Disconnect the battery negative terminal again.
Remove any covers or components obstructing access to the EPS motor.
Detach the EPS motor from the steering column by unscrewing bolts and disconnecting electrical connectors.
Install the new EPS motor by reversing the removal process, ensuring all connections are secure.
Reconnect the battery.

5. Test the System

Reconnect the battery and turn the ignition on.
Check for any warning lights on the dashboard.
Test the steering response by turning the wheel at various speeds.