For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category

### DTC Descriptors

DTC B1370 01: Device Ignition 1 Circuit Short to Battery
DTC B1370 06: Device Ignition 1 Circuit Short to Ground or Open

### DTC Descriptor

DTC B1370 06: Device Ignition 1 Circuit Short to Ground or Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | B1370 06 | B1370 06 | -- | --

### Circuit/System Description

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.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

The SDM detects a short to ground or an open in the ignition 1 voltage circuit for at least 2 seconds when the ignition switch is in RUN or CRANK.

### Action Taken When the DTC Sets

• | 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.

### Conditions for Clearing the DTC

• | The condition for setting the DTC no longer exists.

• | A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

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

1. Ignition OFF, disconnect the X1 harness connector at the SDM and the X2 harness connector at the underhood fuse block.
2. Ignition OFF, test for greater than 1 ohm between the ignition 1 voltage circuit terminal 21 X1 and ground.

⇒ | If less then the specified value, test the circuit for a short to ground.

3. Ignition OFF, test for less than 1 ohm between the ignition 1 voltage circuit terminal 21 X1 and the underhood fuse block terminal 17 X2.

⇒ | If greater then the specified range, test the circuit for an open/high resistance.

4. If all circuits test normal, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SDM replacement, setup, and programming