how to diagnose the B0520 code in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, basic hand tools, and a wiring diagram for reference.
• Disconnect the vehicle battery to ensure safety while working on the airbag system.

2. Inspect Wiring and Connectors

• Remove the passenger seat to gain access to the wiring harness and connectors.
• Visually inspect the wiring for any signs of damage, such as frays or cuts.
• Ensure all connectors are securely fastened and free of corrosion.

3. Test Occupancy Sensor

• Locate the passenger seat occupancy sensor and disconnect it from the wiring harness.
• Use a multimeter to test the resistance of the sensor according to the specifications in the wiring diagram.
• If the sensor is faulty, replace it with a new one.

4. Reconnect and Reassemble

• Reconnect all wiring and connectors that were previously disconnected.
• Reinstall the passenger seat securely, ensuring all bolts are torqued to the manufacturer’s specifications (typically around 25-30 ft-lbs).
• Reconnect the vehicle battery.

5. Clear Codes and Test

• Use the OBD-II scanner to clear any stored codes.
• Start the vehicle and check for the airbag warning light and the passenger airbag status light operation.
• Conduct a test drive to ensure the B0520 code does not reappear.