my Toyota Corolla E170 (2013-2019) has a check engine light and code P0700

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to ensure safety while working on electrical components.

2. Check Transmission Fluid

• Tools Required: Transmission fluid dipstick (if applicable), funnel, clean rag.
• Remove the transmission fluid dipstick and check the fluid level and condition.
  • If low, add the appropriate transmission fluid as specified in the owner's manual.
  • If burnt or contaminated, proceed to drain and replace the fluid.
• Safety Warning: Avoid working on the transmission system while the engine is running.

3. Inspect Wiring and Connectors

• Tools Required: Multimeter, basic hand tools.
• Visually inspect the wiring harness and connectors to the TCM for any signs of wear, fraying, or disconnection.
• Use a multimeter to check for continuity in the wiring and proper voltage at the connectors. Repair or replace any damaged components.

4. Test Transmission Control Module (TCM)

• Tools Required: OBD-II scanner, multimeter.
• Reconnect the battery and use an OBD-II scanner to check for communication with the TCM.
• If communication fails, you may need to replace the TCM.

5. Check Brake Light Switch

• Tools Required: Multimeter, basic hand tools.
• Locate the brake light switch and test its operation using a multimeter.
• If faulty, replace the brake light switch to ensure proper transmission operation.