how to diagnose B1401 code in my Toyota Camry Eighth Generation (2018-present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to prevent electrical shock.
• Ensure the vehicle is parked on a level surface.

2. Replace Cabin Air Filter

• Tools Required: Screwdriver, replacement cabin air filter.
• Locate the cabin air filter access panel, usually found behind the glove compartment.
• Remove the screws or clips securing the panel and gently pull it down to access the filter.
• Remove the old cabin air filter and install the new one, ensuring it is oriented correctly.
• Reattach the access panel and secure it with screws or clips.

3. Inspect and Service A/C Components

• Tools Required: A/C pressure gauge, multimeter.
• Check the A/C compressor operation:
  • Start the engine and turn on the A/C to the maximum setting.
  • Use the A/C pressure gauge to verify the refrigerant pressure; it should be within manufacturer specifications.
• If refrigerant levels are low, locate and repair any leaks before refilling with the correct type and amount of refrigerant.
• Test the A/C relay and fuses:
  • Remove the relay and check for continuity with a multimeter.
  • Replace any faulty relay.

4. Repair Wiring and Connectors

• Tools Required: Wire strippers, electrical connectors, soldering iron (if needed).
• Inspect wiring harnesses and connectors for any signs of wear, fraying, or corrosion.
• Repair or replace damaged wiring and ensure all connections are secure.