System Operation; Sdm Replacement - Chevrolet Captiva Manual

System operation

The SIR system operation is comparable to the
systems used in the current Chevrolet passenger
cars. The addition of the passenger seatbelt
reminder sensor, the new pretensioners and the
curtain do not change the SIR working principle
Passenger seatbelt reminder sensor
When the pressure form the passenger's weight is
higher than a specified value, the SDM recognises
the passenger as present.
If passenger presence is recognised and passenger
seat belt is unbuckled, the SDM will have the pas-
senger warning indicator switched ON. If passen-
ger presence is not recognised, the passenger
warning indicator is switched OFF regardless of
the seat belt being buckled.
Curtain airbag
The side impact sensors trigger the SDM to deploy
the curtain airbags when the impact equals certain
conditions. The curtain airbag system is triggered
by the SDM together with the side airbag system.
Service and Diagnosis

SDM replacement

The Body Control Module (BCM) stores the vehi-
cles restraint ID from the vehicle identification
number (VIN) and the last four digits of the SDMs
part number. When the ignition is switched ON,
the SDM compares this information to the informa-
tion stored in the BCM over the CAN-BUS commu-
nication circuit.
If the information matches, the SDM is in 'Lock
mode'. The airbag warning light goes OFF after
blinking seven times at ignition ON.
If there is a mismatch between the information
stored in the SDM and BCM, DTC B1001 will be
set and the SDM will disable all deployments. The
SDM is in this case in the 'unlock mode' and the
airbag warning lamp flashes at 0.5 Hz continuously
upon switching ON the ignition. Therefore, when
replacing the SDM make sure to program the BCM
using SCAN 100.
Precautions
The SDM can maintain sufficient voltage to deploy
the airbags and pretensioners for 1 minute after
the power has been disconnected. Do not begin
service until one minute after disconnecting power
to the SIR system also known as to 'disable' the
SIR system.
Restraint System
© 2008 General Motors Corporation. All rights reserved.
The SIR system is disabled as follows:
1. Turn the steering wheel to the straight-ahead
position.
2. Turn the ignition switch to LOCK and remove
the key.
3. Remove the airbag fuses F5 and F6 from the I/P-
fuse block and wait more than one minute for
the capacitor to discharge.
The SIR system is enabled as follows:
Insert the airbag fuse F5 and F6 in the I/P-fuse
block.
Turn the ignition switch to ON and verify that the
airbag indicator flashes seven times and turns OFF
The terminals in the SIR are made of special metal
to provide the necessary contact integrity for the
sensitive, low energy circuits.
Do not repair any connectors of supplemental
inflatable restraints (SIR). Replace any damaged
connector with a new one.
Do not attempt to repair any of the SIR wires.
Always replace damaged wires with new wiring.
TRAINING
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