how to diagnose B1650 code on a Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery (negative terminal) to ensure safety while working on the airbag system.

2. Inspect and Repair Wiring

• Remove the passenger seat to access the wiring harness.
• Check for any damaged wires or connectors in the harness leading to the occupant classification sensor.
• Repair or replace damaged wiring as needed.
• Ensure all connectors are securely attached and free from corrosion.

3. Replace Occupant Classification Sensor (if necessary)

• If the occupant classification sensor is found to be faulty, proceed with replacement:
  • Disconnect the wiring harness from the old sensor.
  • Remove the old sensor by unscrewing it from its mounting location.
  • Install the new sensor by reversing the removal steps.
  • Reconnect the wiring harness to the new sensor.

4. Reassemble Components

• Reinstall the passenger seat, ensuring all bolts are tightened to the manufacturer's torque specifications (typically around 30-50 ft-lbs).
• Reconnect the vehicle's battery (positive terminal first, then negative).

5. Clear Codes and Test

• Use the OBD-II scanner to clear the B1650 code.
• Perform a road test to ensure that the airbag system functions correctly and the warning light does not illuminate.