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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the battery to prevent electrical shorts during repair.

2. Fluid Change

1. Drain Transmission Fluid

   • Place a drain pan under the transmission pan.
   • Remove the transmission pan bolts and carefully lower the pan to drain the fluid completely.
   • Tools Required: Socket set, drain pan.

2. Replace Transmission Filter

   • Remove the old filter and replace it with a new one.
   • Ensure the filter is properly seated.
   • Tools Required: Socket set, new transmission filter.

3. Reinstall Transmission Pan

   • Clean the transmission pan and gasket surfaces.
   • Apply a thin bead of RTV gasket maker or use a new gasket.
   • Torque the pan bolts to the manufacturer's specifications (usually around 7-10 ft-lbs).
   • Tools Required: Socket set, torque wrench.

3. Inspect and Repair Wiring

1. Check Wiring Harness
   • Inspect the TCM wiring harness for frays or breaks.
   • Repair or replace any damaged wiring.
   • Tools Required: Wire cutter, soldering iron, heat shrink tubing.

4. TCM Replacement (If Necessary)

1. Remove Old TCM

   • Locate the TCM, typically found near the transmission or under the dashboard.
   • Disconnect the electrical connectors and unscrew the TCM from its mount.
   • Tools Required: Socket set.

2. Install New TCM

   • Position the new TCM and secure it with screws.
   • Reconnect the electrical connectors.
   • Tools Required: Socket set.

5. Final Checks

1. Refill Transmission Fluid
   • Refill the transmission with the appropriate type and amount of fluid as specified in the owner's manual.
   • Tools Required: Funnel.