how to troubleshoot P0700 code on Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, and transmission fluid.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to prevent any electrical shorts while working.

2. Inspect and Replace Transmission Fluid

1. Remove the transmission dipstick and check fluid level.
2. If fluid is low or contaminated:
   • Raise the vehicle using jack stands.
   • Place a drain pan under the transmission pan.
   • Remove the transmission pan bolts using a socket wrench.
   • Carefully lower the pan and drain the fluid.
   • Clean the pan and replace the filter if applicable.
   • Reinstall the pan, torque bolts to manufacturer specifications (typically 8-10 ft-lbs).
   • Fill the transmission with the correct type of fluid (refer to owner’s manual).

3. Check and Repair Wiring/Connectors

1. Locate the transmission control module and associated wiring harness.
2. Inspect for any frayed wires or corroded connectors.
3. Repair or replace damaged wiring and connectors as necessary.
4. Ensure all connections are secure and free of debris.

4. Test Transmission Control Module

1. Reconnect the battery.
2. Use a multimeter to check the voltage and ground at the TCM.
3. If the TCM is not functioning within the specified voltage range, replace it according to the manufacturer’s instructions.

5. Clear Codes and Test Drive

1. Use the OBD-II scanner to clear the P0700 code and any other related codes.
2. Test drive the vehicle to ensure proper shifting and operation of the transmission.
3. Monitor for the reappearance of the check engine light.