Diagnostic Instructions
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
| Short to Ground
| High Resistance
| Open
| Short to Voltage
| Signal Performance
|
Ignition 1 Circuit
| B1370 06
| --
| B1370 06
| B1370 01
| B1370 06
|
Circuit/System Description
The inflatable restraint sensing and diagnostic module (SDM) monitors the ignition 1 signal from the ignition switch. The SDM also compares the ignition 1 input to the power mode message communicated over the vehicle bus. When the vehicle
ignition switch is placed in the RUN or CRANK position, voltage is applied to the SDM ignition 1 input terminal. If a fault is detected in the SDM ignition 1 circuit, 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. |
| • | The SDM sees that the vehicle power mode message is Run/Crank but does not detect the Run/Crank voltage on the ignition 1 input. |
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
The SIR fuse could be open and DTC B1370 will set if the low reference circuit is shorted to voltage/battery with no sensor code set for one of the following sensors:
| • | Right or Left front end sensors |
| • | Right or Left side impact sensors |
Reference Information
Electrical Information Reference
Circuit/System Testing
Important: When removing the connectors inspect for damage or corrosion. Damage or corrosion to the following requires repair or replacement of the affected component/connector:
| • | SDM wiring harness connector |
- Ignition OFF, remove the AIR BAG/DISPLAY fuse at the underhood fuse block.
- Ignition ON, with a DMM, test for 9-16 volts between the voltage supply side of the AIR BAG fuse and ground.
| ⇒ | If not the specified range, refer to
DTC B1370. |
- Ignition OFF, disconnect the harness connector at the SDM.
- Ignition OFF, test for infinite resistance between the ignition 1 voltage circuit terminal 32 and ground.
| ⇒ | If not the specified value, test the B+ circuit for a short to ground. |
- Ignition ON, test for less than 1 volt between the ignition 1 voltage circuit terminal 32 and ground.
| ⇒ | If greater than the specified range, test the B+ circuit for a short to voltage. |
- Ignition OFF, test for less than 1 ohm between the ignition 1 voltage circuit terminal 32 and the AIR BAG fuse terminal K4 C4 at the underhood fuse block.
| ⇒ | If greater than the specified range, test the B+ circuit for an open/high resistance. |
- If all circuits test normal, replace the SDM.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
