how to fix P0700 transmission fault code in Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Disconnect the vehicle's battery negative terminal to ensure safety while working on electrical components.

2. Inspect and Replace Transmission Fluid

• Tools Required: Socket set, fluid pump, drain pan.
• Sub-steps:
  1. Locate the transmission fluid drain plug and place the drain pan underneath.
  2. Remove the drain plug and allow the fluid to completely drain.
  3. Inspect the old fluid; if it appears dark or has a burnt smell, it needs replacement.
  4. Reinstall the drain plug and torque it to the manufacturer's specifications.
  5. Use a fluid pump to fill the transmission with new fluid according to the specifications in the owner's manual.

3. Check and Repair Electrical Connections

• Tools Required: Multimeter, wire brush, dielectric grease.
• Sub-steps:
  1. Inspect the wiring harness and connectors leading to the TCM for signs of wear or damage.
  2. Clean corroded connectors using a wire brush.
  3. Apply dielectric grease to prevent future corrosion.
  4. Ensure all connectors are secure and properly seated.

4. Replace Transmission Control Module (if necessary)

• Tools Required: Socket set, screwdrivers.
• Sub-steps:
  1. Locate the TCM, usually found near the transmission or under the dashboard.
  2. Disconnect the electrical connectors from the TCM.
  3. Remove any mounting bolts or screws securing the TCM.
  4. Install the new TCM by reversing the removal steps.
  5. Reconnect all electrical connectors securely.

5. Reconnect Battery and Clear Codes

• Reconnect the battery's negative terminal.
• Use the OBD-II scanner to clear the P0700 code and any associated codes.