how to fix P0700 transmission control system malfunction in Toyota Highlander Fourth Generation (202...

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and engage the parking brake.
• Disconnect the battery to prevent electrical shorts during repairs.

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Locate the transmission dipstick and remove it to check fluid level.
  2. If fluid is low, top off with Toyota Genuine ATF WS fluid.
  3. If fluid is dirty or burnt, drain the old fluid by removing the drain plug.
  4. Replace the transmission filter if equipped, and refill with fresh fluid.

3. Inspect and Repair Wiring

• Sub-steps:
  1. Remove the plastic cover to access the wiring harness connected to the TCM.
  2. Visually inspect the wiring for frays or breaks, and repair or replace any damaged sections.
  3. Clean any corroded connectors with electrical contact cleaner.

4. Replace TCM (if necessary)

• Sub-steps:
  1. Remove the screws or bolts securing the TCM in place.
  2. Disconnect the wiring harness from the TCM.
  3. Install the new TCM and reconnect the wiring harness.
  4. Secure the TCM with screws or bolts to ensure it is properly mounted.

5. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0700 code.
  3. Start the vehicle and perform a test drive to ensure proper shifting and operation.