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 the voltage difference, the SDM is able to calculate the
driver loop resistance. A low loop resistance indicates the two driver cirucits are
shorted together.
Conditions for Setting the DTC
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. |
| • | The Fault is present for half a second. |
Action Taken When the DTC Sets
| • | The air bag telltale will be on. |
Diagnostic Aids
| • | When attempting to diagnose an intermittent driver loop fault, use the
scan tool to monitor the current DTCs. Wiggle the wires, turn the steering wheel,
and check connections while watching for a current DTC to appear and/or disappear
on the scan tool. |
| • | Always start diagnosis of the SIR DTCs with an inspection of the wiring
and components for the visible damage. |
| • | A malfunctioning shorting bar at the driver inflator module or lower steering
column connector could cause this DTC. |
B0022
