Supplemental Inflatable Restraints
DTC B1370
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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 requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
* The SDM stores DTC to memory.
* 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
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
Diagnostic Aids
A history DTC maybe caused by an intermittent short or open in the ignition 1 circuit.
Reference Information
Schematic Reference
SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
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 component/connector.
* SDM module
* SDM wiring harness connector
1. Ignition OFF, remove the AIR BAG fuse from the BCM fuse center. Ignition ON, engine OFF, test for 9-16 volts between the voltage supply side of the fuse and ground.
• If not within the specific range, refer to DTC B1370-B1379, B1380-B1389, or B1440-B1443 (B1370).
2. Disconnect the SDM harness connector.
3. Disconnect the BCM harness connector X3.
4. Ignition OFF, test for less than 1 ohm between the BCM ignition 1 voltage circuit terminal D7 X3 and the SDM terminal 33.
• If greater then the specified range, test the circuit for an open/high resistance.
5. Test for infinite resistance between the SDM ignition 1 voltage circuit terminal 33 and ground.
• If less than the specified range, test the circuit for short to ground.
6. Ignition ON, test for less than 1 volt between the SDM ignition 1 voltage circuit terminal 33 and ground.
• If greater then the specified value, test the circuit for a short to voltage.
7. If all circuits test normal then replace the SDM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* SIR/SRS Wiring Repairs (SIR/SRS Wiring Repairs)
* Programming and Relearning (Programming and Relearning) for BCM and SDM replacement, setup, and programming