how to diagnose error code B1242 on Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather necessary tools and safety equipment.
• Disconnect the vehicle's battery to prevent electrical shock.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks.

2. Inspect and Replace Fuses

• Locate the fuse box (usually under the dashboard or in the engine compartment).
• Remove the cover and check the relevant fuses for the A/C system.
• Replace any blown fuses with new ones of the correct amperage.

3. Repair Wiring and Connectors

• Inspect the wiring harness leading to the A/C inverter.
• If damage or corrosion is found, repair or replace the affected wiring and connectors.
• Ensure all connections are secure and free of debris.

4. Test and Replace A/C Inverter

• If the previous steps do not resolve the issue, test the A/C inverter using a multimeter for proper amperage and voltage.
• If the inverter is faulty, remove it by disconnecting the wiring harness and unscrewing it from its mount.
• Install the new A/C inverter by securing it in place and reconnecting the wiring.

5. Refill Refrigerant (if necessary)

• Connect a refrigerant gauge set to the A/C system service ports.
• Check the pressure readings and refill the system with the manufacturer-recommended refrigerant type if levels are low.

6. Reassemble and Test

• Reconnect the battery and start the vehicle.
• Activate the A/C system and monitor for proper operation and any reappearance of the error code.