Restraint System Diagnosis

DTC B1370

DTC DESCRIPTOR

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






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

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 via serial data communications.
- 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.

CIRCUIT/SYSTEM TESTING
1. Ignition ON, use the scan tool checks for DTCs. Verify that DTC P2535 in the BCM does not set.
- The SDM module
- The SDM wiring harness connector
- If DTC P2535 is current go to DTC P2535.

IMPORTANT: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

2. Ignition OFF, remove the Air Bag fuse from the BCM fuse center. Ignition ON, engine OFF test the voltage side of the Air Bag fuse with a DMM. Measure the voltage of the Air Bag fuse voltage side and ground. The voltage should read 9-16 volts.
- If the voltage is less than 9-16 volts refer to DTC B1370.
3. Remove the SDM connector.
4. With the Air Bag fuse removed, test the ignition 1 voltage circuit between the BCM fuse center and the SDM for a short to voltage or an open. Verify that a short to voltage or an open does not exist.
- If any of the above conditions are found make the appropriate repair.
5. If all circuits test normal then replace the SDM.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for BCM and SDM replacement, setup, and programming.