Test Notes

Fault Code 21-LH Cowl Side Panel Air Bag Sensor Not Mounted to Vehicle Properly

Normal Operation

Circuit 613 (DB/W) is riveted to the side housing of LH cowl side air bag sensor and bracket. The housing is grounded to the vehicle. A resistor inside the air bag diagnostic monitor is connected to pin 16 (circuit 613 DB/W) and a 5-volt reference voltage. If circuit 613 is properly grounded, the voltage at pin 16 will be 0 volts. If the voltage on circuit 613 is greater than 0.7 volts, the air bag diagnostic monitor may flash diagnostic trouble code 21, indicating that the LH cowl side air bag sensor and bracket 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 sensor mounting surface.
2. An open or damaged wire in circuit 613 (DB/W) from pin 16 of the diagnostic monitor connector to the LH cowl side air bag sensor and bracket.
3. An open wire or loose rivet inside the LH cowl side air bag sensor and bracket.