For 1990-2009 cars

### Circuit Description

When the ignition switch is turned ON and during vehicle operation, the SDM performs tests to detect faults. While the SDM is performing tests to detect system faults, tests are also performed on internal components of the SDM. When an internal SDM fault is detected this DTC is set.

### DTC Parameters

DTC B1000 can be set when the SDM malfunctions. The following conditions must be met to set this DTC:

• | Ignition voltage is present at the SDM and continuous.

• | The SDM has detected an internal fault or an air bag deployment has been commanded.

• | Fault is present for half a second.

### Action Taken

• | DTC B1000 will set.

• | The air bag telltale will be ON.

### Diagnostic Aids

• | Always start diagnosis of SIR DTCs with an inspection of vehicle, including its wiring and SIR components for visible damage.

• | Always replace SDMs with a DTC B1000 set, only after all collision repairs have been completed.

• | Always perform the Diagnostic System Check - SIR procedure before using this chart.