GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 DTC 🢒 DTC B1370

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 Descriptors

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

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 10 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

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 IGN 1 AIR BAG fuse.
  2. Ignition ON, with a DMM, test for 9-16 V between the voltage supply side and ground.
    3. ⇒If not the specified range, refer to DTC B1370.
  3. Ignition OFF, disconnect the harness connector at the SDM.
  4. Ignition OFF, disconnect the X2 harness connector at the IP fuse block.
  5. Ignition OFF, test for less than 1 ohm between the ignition 1 voltage circuit terminal 32 and the IP fuse block terminal 10 (X2).
    6. ⇒If greater then the specified range, test the circuit for an open/high resistance.
  6. Ignition ON, test for less than 1 volt between the ignition 1 voltage circuit terminal 32 and the IP fuse block terminal 10 (X2).
    7. ⇒If greater then the specified value, test the circuit for a short to voltage.
  7. 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
    •  SIR/SRS Wiring Repairs