Test Notes

Normal Operation
The air bag diagnostic monitor measures the resistance between the ground connection at its bracket and the reference ground at Pin C232-18, Circuit 570 (BK/W). If a difference of more than 3.0 ohms between the ground at Pin C232-18 and the air bag diagnostic monitor bracket ground, the air bag diagnostic monitor will store a Diagnostic Trouble Code (DTC) B1921 in memory and flash a Lamp Fault Code (LFC) 21 on the air bag indicator to indicate a possible open ground circuit. Should the difference of more than 3.0 ohms of resistance between Pin C232-18, Circuit 570 (BK/W) and the air bag diagnostic monitor bracket ground be intermittent or repaired, the air bag diagnostic monitor will store a DTC B1921 in memory.

Possible Causes
A high resistance reading at the air bag diagnostic monitor bracket ground can be caused by:
- poor attachment of the air bag diagnostic monitor due to loose mounting, dirt, or corrosion at the air bag diagnostic monitor bracket mounting surface.
- a poor reference ground at Pins C233-10 and C232-18. Circuit 570 (BK/W) of the air bag diagnostic monitor.