how to resolve the P0456 code in my Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

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

2. Inspect and Replace the Gas Cap

• Tools Required: None specifically for this step.
• Instructions:
  1. Remove the gas cap and inspect the rubber seal for cracks or wear.
  2. If damaged, replace it with a new gas cap that matches the specifications for the vehicle.

3. Inspect and Replace EVAP Hoses

• Tools Required: Pliers, socket set.
• Instructions:
  1. Locate the EVAP hoses connected to the fuel tank, purge valve, and vent valve.
  2. Check for any cracks or loose connections.
  3. If any hoses are damaged, remove them using pliers and replace with new hoses that meet OEM specifications.
  4. Ensure all connections are tight and secure.

4. Test and Replace EVAP Valves

• Tools Required: Multimeter, socket set.
• Instructions:
  1. Identify the EVAP purge and vent valves.
  2. Disconnect the electrical connectors and use a multimeter to test continuity.
  3. If either valve is defective, remove it by unbolting it from its mounting location and replace it with a new valve.
  4. Reconnect the electrical connectors and ensure the valves operate correctly.

5. Smoke Test for Leaks

• Tools Required: Smoke machine.
• Instructions:
  1. Connect the smoke machine to the EVAP service port.
  2. Activate the smoke machine to introduce smoke into the EVAP system.
  3. Observe for any smoke escaping from hoses, connections, or the fuel tank.
  4. Repair any identified leaks as necessary.

6. Reconnect Battery and Clear Codes

• Instructions:
  1. Reconnect the negative battery terminal.
  2. Use an OBD-II scanner to clear the P0456 code from the vehicle's memory.