how to diagnose CVT issues in Toyota Highlander Third Generation (2014-2019)

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

3 min read

565 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 CVT issues in Toyota Highlander (2014-2019). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Transmission

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Allow the engine to cool before opening the transmission fluid fill plug.

Symptoms

•Check engine light illuminated
•Slipping or harsh shifting during acceleration
•Unusual noises (grinding or whining) from the transmission
•Delayed response when shifting into drive or reverse
•Fluid leaks under the vehicle
•Overheating warning on the dashboard

Diagnostic Steps

1
Scan for trouble codes using an OBD-II scanner to identify any transmission-related error codes.
2
Check the transmission fluid level and condition; look for signs of contamination or burnt smell.
3
Inspect the CVT fluid cooler for blockages or leaks.
4
Examine the transmission wiring harness and connectors for damage or corrosion.
5
Test the CVT solenoids for proper function using a multimeter.
6
Perform a road test to assess the performance and replicate the symptoms.

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
•Transmission fluid
•Funnel
•Safety gloves

Parts Required

•Toyota-approved CVT fluid
•Replacement solenoids (if necessary)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan for trouble codes using an OBD-II scanner to identify any transmission-related error codes.
2
Check the transmission fluid level and condition; look for signs of contamination or burnt smell.
3
Inspect the CVT fluid cooler for blockages or leaks.
4
Examine the transmission wiring harness and connectors for damage or corrosion.
5
Test the CVT solenoids for proper function using a multimeter.
6
Perform a road test to assess the performance and replicate the symptoms.

Solution

1. Preparation

Gather tools: OBD-II scanner, multimeter, socket set, transmission fluid, funnel, and safety gloves.
Ensure the vehicle is parked on a level surface and the engine is turned off.
Disconnect the negative battery terminal to avoid electrical shorts.

2. Fluid Change

Sub-steps:
1. Locate the transmission drain plug and remove it using a socket wrench.
2. Allow the old CVT fluid to completely drain into a suitable container.
3. Replace the drain plug and torque it to manufacturer's specifications (typically around 30 lb-ft).
4. Remove the fill plug and use a funnel to add the new CVT fluid, ensuring to use Toyota-approved CVT fluid.
5. Start the engine and cycle through the gears to allow fluid distribution.
6. Recheck the fluid level and add more if necessary.

3. Solenoid Inspection

Sub-steps:
1. Locate the transmission solenoid assembly as per the service manual.
2. Disconnect the electrical connectors from the solenoids.
3. Use a multimeter to test for resistance according to the specifications (typically around 11-14 ohms).
4. Replace any solenoids that are out of specification.

4. Wiring Inspection

Sub-steps:
1. Visually inspect the wiring harness for frayed wires or damaged connectors.
2. Use a multimeter to check for continuity in the wiring from the transmission control module to the solenoids.
3. Repair or replace any damaged wiring or connectors.

5. Final Checks

Sub-steps:
1. Reconnect the battery terminal.
2. Start the vehicle and check for any warning lights.
3. Take the vehicle for a test drive to ensure smooth operation and no recurrence of symptoms.