Circuit Description
When the ignition switch is turned ON and during vehicle operation, the SDM
performs tests to detect system faults. One test the SDM performs is to monitor the
driver deployment loop high circuit and driver deployment loop low circuit voltage
difference. By monitoring voltage difference, the SDM is able to calculate the driver
loop resistance. A low loop resistance indicates the two driver circuits are shorted
together.
DTC Parameters
DTC B0022 can be set when the driver loop resistance is low. The following
conditions must be met to set this DTC:
| • | Ignition voltage is present at the SDM and continuous. |
| • | The driver deployment loop resistance is under 1.3 ohms. |
| • | Fault is present for half a second. |
Action Taken
| • | The air bag telltale will be ON. |
Diagnostic Aids
| • | When attempting to diagnose an intermittent driver loop fault, use the
scan tool to monitor current DTCs. Wiggle wires, turn steering wheel, and check connections
while watching for a current DTC to appear and/or disappear on the scan tool. |
| • | Always start diagnosis of SIR DTCs with an inspection of wiring and components
for visible damage. |
| • | A malfunctioning shorting bar at the driver inflator module or lower steering
column connector could cause this DTC. |
