For 1990-2009 cars

### Diagnostic Instructions

• | 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.

### DTC Descriptor

DTC B1370 06: Device Ignition 1 (On and Start) Circuit Short to Battery

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | B1370 06 | B1370 06 | -- | --
Run/Crank Relay Coil Control | 1 | 1 | 1 | --
1. A fault in this circuit will cause multiple symptoms including no start and may cause B1370 in the SDM.

### Circuit/System Description

The inflatable restraint sensing and diagnostic module (SDM) monitors the ignition 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 input terminal. If an open or short to ground in this SDM ignition 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 voltage circuit for greater than 10 seconds when the ignition switch is in RUN or CRANK.

### Action Taken When the DTC Sets

• | The SDM commands the AIR BAG indicator ON.

• | The SDM determines its power mode only from the serial data power mode messages and discards the ignition 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

#### Description and Operation

SIR System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Connector 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, remove the underhood AIRBAG fuse.
2. Ignition ON, connect a test lamp between the B+ side to the fuse and ground. The test lamp should illuminate.

⇒ | If the test lamp does not illuminate, refer to DTC B1370-B1379, B1380-B1389, or B1440-B1443.

3. Ignition OFF, install the underhood AIRBAG fuse.
4. Disconnect the harness connector at the SDM.
5. Ignition ON, verify a test lamp illuminates between ignition circuit terminal 33 and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for short to ground or an open/high resistance.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | SIR/SRS Wiring Repairs

• | Control Module References for SDM replacement, setup, and programming