B1370 - Device Ignition 1 Circuit - SDM

DTC B1370

CIRCUIT 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.

DTC DESCRIPTOR




This diagnostic procedure supports the following DTC:
DTC B1370 Device Ignition 1 Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms refer to DTC Symptom Description in Vehicle DTC Information. DTC Symptom Description

CONDITIONS FOR RUNNING THE DTC
Ignition 1 voltage is within the normal operating range of 9-16 volts.

CONDITIONS FOR SETTING THE DTC

B1370 01
- The SDM detects a short to battery in the ignition 1 voltage circuit when the switch is in the OFF position.
- This condition is present at least 10 seconds.

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.
- This condition is present at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The SDM commands the AIR BAG indicator ON via GMLAN serial data.
- 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.

TEST DESCRIPTION

Steps 1-11:

Step 12:

The numbers below refer to the step numbers on the diagnostic table.
6. This tests the Air Bag ignition 1 voltage circuit for a short or open.
7. This tests the Run/Crank voltage circuit between the relay and fuse.
9. This tests the Run/Crank voltage circuit for an short or open.