Supplemental Inflatable Restraints

DTC B1370

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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

Diagnostic Fault Information






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, short to voltage, 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 following conditions exist for at least 10 seconds.

B1370 01

The SDM detects a short to battery in the ignition 1 voltage circuit when the switch is in the OFF position.

B1370 06

The SDM detects a short to ground or an open in the ignition 1 voltage circuit 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 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.

Diagnostic Aids

A history DTC maybe caused by an intermittent short or open in the ignition 1 circuit.

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 AIR BAG IGN fuse 39.
2. Ignition ON, test for 9-16 V between the voltage supply side and ground.

• If not within the specified range, refer to DTC B1370.

3. Ignition OFF, remove the SDM harness connector.
4. Ignition OFF, test for less than 1 ohm between the ignition 1 voltage circuit terminal 32 and the underhood fuse block terminal G2 (X5).

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

5. Ignition ON, test for less than 1 volt between the SDM harness connector ignition 1 voltage circuit terminal 32 and the underhood fuse block terminal G2 (X5).

• If greater then the specified value, test the circuit for a short to voltage.

6. If all circuits test normal, reconnect all connectors, replace fuse, clear all DTCs. If DTC B1370 stays current, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* SIR/SRS Wiring Repairs