how to fix P0700 transmission code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Transmission Fluid

• Tools Required: Socket set, torque wrench, funnel, transmission fluid pump.
• Check the transmission fluid level using the dipstick. If low, add manufacturer-recommended transmission fluid (typically Toyota ATF WS).
• If fluid is dirty or burnt, drain and replace it:
  1. Remove the transmission pan bolts (use a socket wrench).
  2. Carefully lower the pan and drain the old fluid into a container.
  3. Clean the pan and replace the filter if equipped.
  4. Reinstall the pan with a new gasket, tightening bolts to the manufacturer’s torque specifications.
  5. Refill with new transmission fluid through the dipstick tube.

3. Inspect and Repair Electrical Connections

• Tools Required: Multimeter, wire strippers, soldering kit.
• Visually inspect the wiring harness and connectors going to the TCM for damage.
• Use a multimeter to check for continuity in the wiring.
• Repair any damaged wires using appropriate connectors or soldering.

4. Replace Transmission Control Module (if necessary)

• Tools Required: Torque wrench, socket set.
• If diagnostics indicate a faulty TCM:
  1. Locate the TCM (usually under the dashboard or near the transmission).
  2. Disconnect the battery and remove the TCM connectors.
  3. Unbolt the TCM from its mounting location.
  4. Install the new TCM in reverse order, securing it with bolts to manufacturer specifications.
  5. Reconnect the battery.