Why does my 2021 Toyota Highlander have trouble shifting gears?

Problem Diagnosis: Trouble Shifting Gears in a 2021 Toyota Highlander

Tools Required

• OBD-II Scanner
• Transmission fluid dipstick or funnel
• Socket set (for transmission pan removal if necessary)
• Torque wrench
• Fluid pump (for adding fluid if needed)
• Safety equipment (gloves, safety glasses)

Repair Instructions

Step 1: Retrieve Diagnostic Codes

1. Connect the OBD-II scanner to the vehicle's port (usually located under the dashboard).
2. Turn the ignition to the ON position without starting the engine.
3. Follow the scanner's instructions to retrieve and note any codes related to the transmission.

Step 2: Check Transmission Fluid

1. Warm Up the Vehicle: Start the engine and let it idle for a few minutes to warm up the transmission fluid.

2. Fluid Level Check:

   • With the engine running, pull out the transmission dipstick (if equipped) and wipe it clean.
   • Reinsert the dipstick and pull it out again to check the fluid level.
   • If the fluid is low, add the appropriate type of Toyota ATF (Automatic Transmission Fluid) through the dipstick tube using a funnel.

3. Fluid Condition Check:

   • If the fluid is dark or has a burnt smell, it may need to be changed. If contaminated, consider flushing the system.

Step 3: Perform a Visual Inspection

1. Examine the transmission for leaks and the condition of the transmission pan.
2. Check the wiring connectors for the TCM and solenoids. Disconnect and inspect for corrosion or damage.

Step 4: Test the Transmission

1. If no DTCs indicate a specific issue, consider resetting the TCM by disconnecting the battery for 10 minutes.
2. Reconnect the battery and take the vehicle for another test drive to see if the shifting improves.

Step 5: Further Repair (if applicable)

• Replace Transmission Fluid: If fluid is contaminated, consider a full transmission fluid and filter change.
• Check the Filter: If you have previously changed the fluid, consider replacing the transmission filter.
• Inspect Solenoids: If issues persist, further diagnose the TCM and solenoids. You may need a professional to test these components.

Step 6: Professional Assistance

• If the problem persists despite all checks, consider taking the vehicle to a certified Toyota technician or dealership for further diagnostics or potential transmission repair/replacement.

Conclusion

Addressing shifting issues in your 2021 Toyota Highlander can often be resolved with a thorough inspection of the fluid and diagnostics with an OBD-II scanner. However, persistent issues may require more in-depth inspection or professional assistance. Always ensure that you are using the correct transmission fluid and follow manufacturer guidelines for maintenance.