Test Notes

Normal Operation
Circuit 613 (BL/W) is riveted to the side of the rear safing sensor housing and the housing is grounded to the vehicle. A resistor inside the diagnostic monitor is connected to pin 16 (Circuit 613 (BL/W)) and a 5 volt reference voltage. If Circuit 613 (BL/W) is properly grounded, the voltage at Pin 16 will be 0 volts. If the voltage on Circuit 613 (BL/W) is greater than 0.7 volt, the diagnostic monitor may flash a code 21, indicating that the rear safing sensor is not grounded properly to the vehicle.

Possible Causes
High voltage at pin 16 can be caused by:
1. A poor connection due to loose mounting, dirt, or corrosion at the rear safing sensor mounting surface.
2. An open or damaged wire in Circuit 613 (BL/W) from pin 16 of the diagnostic monitor connector to the rear safing sensor.
3. An open wire or loose rivet inside the rear safing sensor.