my Toyota Highlander Third Generation (2014-2019) doesn’t engage in 4WD what should I check

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

3 min read

538 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 the 4WD engagement issue in Toyota Highlander 2014-2019. Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

Transmission

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems to avoid shocks or shorts.
•Allow the vehicle to cool down if working on the drivetrain components.

Symptoms

•4WD indicator light does not illuminate on the dashboard
•No change in traction or handling when attempting to engage 4WD
•Abnormal noises when switching to 4WD
•Warning lights related to the drivetrain illuminated
•Difficulty in navigating slippery surfaces indicating a lack of 4WD functionality

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for any related fault codes.
2
Inspect the 4WD control switch for any visible damage or signs of malfunction.
3
Check the transfer case fluid level and condition; low or contaminated fluid can affect operation.
4
Examine the wiring and connectors to the transfer case motor for damage or corrosion.
5
Test the transfer case actuator for functionality using a multimeter.
6
Inspect the front and rear differentials for any signs of damage or excessive wear.

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
•Socket set
•Multimeter
•Trim removal tool
•Torque wrench

Parts Required

•Transfer case fluid (Toyota ATF WS)
•4WD control switch (if faulty)
•Transfer case actuator (if faulty)

Related Faults

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Symptoms

•4WD indicator light does not illuminate on the dashboard

•No change in traction or handling when attempting to engage 4WD

•Abnormal noises when switching to 4WD

•Warning lights related to the drivetrain illuminated

•Difficulty in navigating slippery surfaces indicating a lack of 4WD functionality

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for any related fault codes.
2
Inspect the 4WD control switch for any visible damage or signs of malfunction.
3
Check the transfer case fluid level and condition; low or contaminated fluid can affect operation.
4
Examine the wiring and connectors to the transfer case motor for damage or corrosion.
5
Test the transfer case actuator for functionality using a multimeter.
6
Inspect the front and rear differentials for any signs of damage or excessive wear.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a flat surface and the engine is off.
Disconnect the battery to prevent electrical shorts.

2. Check and Replace Transfer Case Fluid

Sub-steps:
1. Locate the transfer case drain plug and remove it using a socket wrench.
2. Drain the old fluid into a suitable container.
3. Inspect the fluid for metal shavings or a burnt smell; replace if necessary.
4. Refill with manufacturer-recommended transfer case fluid (Toyota ATF WS).
5. Reinstall the drain plug and torque it to the manufacturer’s specifications.

3. Inspect and Replace 4WD Control Switch

Sub-steps:
1. Remove the center console panel using a trim tool.
2. Disconnect the wiring harness from the 4WD control switch.
3. Test the switch for continuity using a multimeter.
4. If faulty, replace the switch with an OEM part.
5. Reconnect the wiring and reassemble the console.

4. Test Transfer Case Actuator

Sub-steps:
1. Locate the transfer case actuator on the transfer case.
2. Disconnect the electrical connector from the actuator.
3. Use a multimeter to check for voltage at the connector when the 4WD switch is activated.
4. Replace the actuator if it does not receive power or fails to engage.
5. Reconnect the actuator and check for proper operation.