how to fix P0700 transmission trouble code on Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, and screwdrivers.
• Ensure the vehicle is parked on a level surface and the engine is turned off before starting work.

2. Transmission Fluid Inspection and Change

• 1.1. Remove the transmission dipstick and check fluid level.
• 1.2. If fluid is low, top off with Toyota Type T-IV transmission fluid.
• 1.3. If fluid is dirty or burnt, drain the transmission fluid by removing the drain plug.
• 1.4. Replace with new Toyota Type T-IV fluid, ensuring proper amount based on the vehicle's specifications (approximately 4-5 quarts for a drain and refill).

3. Wiring and Connector Inspection

• 3.1. Carefully inspect the wiring harness connected to the TCM for any frays or signs of wear.
• 3.2. Disconnect the connectors, clean them with electrical contact cleaner, and reconnect securely.
• 3.3. Replace any damaged wiring or connectors as necessary.

4. TCM Testing

• 4.1. Using a multimeter, check the voltage at the TCM harness while the ignition is in the ON position (should be around 12V).
• 4.2. If voltage is not present, trace the wiring back to the battery and fuse box for any breaks.
• 4.3. If voltage is present but the P0700 persists, consider replacing the TCM.

5. Transmission Range Sensor Check

• 5.1. Locate the transmission range sensor and check for proper alignment and secure mounting.
• 5.2. Test the sensor's output voltage while moving the gear selector through all positions with a multimeter.
• 5.3. Replace the sensor if readings are out of spec or if it fails to return to the neutral position.