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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, fluid catch pan, funnel, rags.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Address Fluid Issues

• Check and Replace Fluid:
  1. Remove the transmission dipstick and check fluid level.
  2. If low, add the recommended ATF (Toyota WS fluid) to the appropriate level.
  3. If fluid is contaminated or burnt, proceed with fluid replacement.
  4. Drain the old fluid using a catch pan, replace the transmission pan gasket if necessary, and refill with new fluid.

3. Repair or Replace Components

• Transmission Filter Replacement:
  1. Remove the transmission pan bolts using a socket set.
  2. Carefully lower the pan; allow any remaining fluid to drain.
  3. Remove the old transmission filter and replace it with a new one.
  4. Reinstall the transmission pan with a new gasket and torque bolts to manufacturer specifications (typically around 8 ft-lbs).

4. Electrical Inspection

• Repair Electrical Components:
  1. Inspect wiring harness and connectors for breaks or corrosion.
  2. If damaged, repair or replace the affected wiring or connectors.
  3. Clear any DTCs using the OBD-II scanner.

5. Test Drive

• After completing repairs, conduct a test drive to ensure that the transmission operates smoothly without slipping or harsh shifting.