how to resolve P0700 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather required tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Check and Replace Transmission Fluid

• Tools Required: Socket set, transmission fluid pump, fluid catch pan.
• Remove the transmission fluid drain plug and allow old fluid to drain completely into a catch pan.
• Replace the drain plug and torque to manufacturer's specifications.
• Using a transmission fluid pump, refill the transmission with the correct type of fluid as specified in the owner's manual until it reaches the proper level.

3. Inspect and Repair Wiring/Connectors

• Visually inspect the wiring harness and connectors leading to the transmission control module.
• If any wiring is frayed or connectors are corroded, repair or replace as necessary.
• Ensure all connections are secure.

4. Replace Transmission Control Module (if necessary)

• Tools Required: Socket set, trim removal tool.
• Locate the TCM (typically near the transmission or under the dashboard).
• Disconnect the wiring harness from the TCM.
• Remove the TCM mounting bolts and carefully take out the module.
• Install the new TCM, ensuring it is seated properly, and reconnect the wiring harness.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the vehicle and allow it to idle for a few minutes.
• Shift through all gears to ensure proper operation of the transmission.