Chevrolet Cruze manuals

Chevrolet Cruze Repair Manual: Frontal SIR System Description

The frontal supplemental inflatable restraint (SIR) system consists of the following components:

A frontal collision of sufficient force will deploy the frontal air bags and/or pretensioners. The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts vehicle velocity changes to an electrical signal. The SDM compares these signals to values stored in memory. If the signals exceed a stored value, the SDM will determine the severity of the impact and either cause current to flow through the frontal deployment loops deploying the frontal air bags and pretensioners, or it will deploy the pretensioners only. The SDM, instrument panel module, steering wheel module, steering wheel module coil, seat belt retractor pretensioners, and the connecting wires make up the frontal deployment loops. The SDM continuously monitors the deployment loops for malfunctions and illuminates the AIR BAG indicator if a fault is detected.

Inflatable Restraint Sensing and Diagnostic Module (SDM)

The inflatable restraint sensing and diagnostic module (SDM) is a microprocessor and the control center for the supplemental inflatable restraint (SIR) system. The SDM contains internal sensors along with several external sensors, if equipped, mounted at strategic locations on the vehicle. In the event of a collision, the SDM compares the signals from the internal and external sensors to a value stored in memory. When the generated signals exceed the stored value, the SDM will cause current to flow through the appropriate deployment loops to deploy the air bags. The SDM records the SIR system status when a deployment occurs and illuminates the AIR BAG indicator located in the instrument cluster. The SDM performs continuous diagnostic monitoring of the SIR system electrical components and circuitry when the ignition is turned ON. If the SDM detects a malfunction, a DTC will be stored and the SDM will request the instrument cluster to illuminate the AIR BAG indicator, notifying the driver that a malfunction exists. In the event that ignition positive voltage is lost during a collision, the SDM maintains a 23-volt loop reserve for deployment of the air bags. It is important when disabling the SIR system for servicing or rescue operations to allow the 23-volt loop reserve to dissipate, which could take up to 1 minute.

SIR System Description and Operation
SIR System Overview The supplemental inflatable restraint (SIR) system supplements the protection offered by the occupants Seat Belt System (2). The SIR system may contain several inflator mod ...

Inflatable Restraint Passenger Presence Detection System - If Equipped
Note: The passenger presence detection system includes an ECU and a sensor mat that can be serviced separately. After repairing or replacing any part of the passenger presence detection system, the ...

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Installation Procedure
Note: If the location of the original plug weld holes can not be determined, space the plug weld holes every 40 mm (1½ in). Drill 8 mm (5/16 in) for plug welding along the edges of the body rear end panel as noted  from the original panel. Clean and prepare the attaching s ...

Driver Seat Frame Replacement
Removal Procedure Remove front seat cushion cover (1) and pad (2) from frame (3). Refer to Front Seat Cushion Cover and Pad Replacement Remove the wire harness (1), if equipped. Remove front seat back cushion cover (1) and pad (2) from frame (3). Refer to Driver or ...

Installation Procedure
Create 6 x 20 mm (4/16 x 11/16 in) slots for MIG-brazing along the upper edges of the service panel as noted from the original panel. Clean and prepare the attaching surfaces for brazing and spot welding. Position the body lock pillar inner panel on the vehicle. Verify the ...

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