| • | Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure. | 
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. | 
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. | 
Circuit  | Short to Ground  | High Resistance  | Open  | Short to Voltage  | Signal Performance  | 
|---|---|---|---|---|---|
Ignition 1 Voltage  | B1370 06  | --  | B1370 06  | --  | B1370 06  | 
Run/Crank Relay Coil Control  | 1  | --  | 1  | 1  | 1  | 
1. A fault in this circuit will cause multiple symptoms including no start and may cause B1370 in the SDM.  | |||||
The inflatable restraint sensing and diagnostic module (SDM) monitors the ignition 1 signal from the ignition switch. When the vehicle ignition switch is placed in the RUN or CRANK position, the switch supplies voltage to the SDM ignition 1 input terminal. If an open or short to ground in this SDM ignition 1 circuit is detected, then DTC B1370 will set.
Ignition voltage is between 9-16 volts.
The SDM detects a short to ground or an open in the ignition 1 voltage circuit for at least 10 seconds when the ignition switch is in RUN or CRANK.
| • | The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator. | 
| • | The SDM determines its power mode only from the GMLAN power mode messages and discards the ignition 1 input for the remainder of the ignition cycle. | 
| • | The condition for setting the DTC no longer exists. | 
| • | A history DTC will clear once 100 malfunction-free ignition cycles have occurred. | 
SIR System Description and Operation
Control Module References for scan tool information
Important: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected.
   •  SDM     •  SDM wiring harness 
| ⇒ | If not within the specified range, refer to DTC B1370. | 
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. | 
| ⇒ | If greater than the specified value, test the circuit for a short to voltage. | 
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for SDM replacement, setup, and programming |