Page 833 of 1184
8B–6 SUPPLEMENTAL INFLATABLE RESTRAINTS (SIR)
DAEWOO M-150 BL2
D110B002
AIRBAG DEPLOYMENT PROCEDURE
1. Non–Deployment condition
a. Initiator
b. Piston
c. Safety disc
d. Compressed Ar gas
D110B003
2. When crashing, firing current flows from the SDM to
the initiator.
3. Initiator is burning and the inside pressure is increas-
ing and the piston hits the safety disc.
D110B004
4. Safety disc is broken and the compressed Ar gas is
spouted out.
D110B005
5. Compressed Ar gas and the burned initiator are car-
bureted. And the airbag is deployed.
Page 834 of 1184
SUPPLEMENTAL INFLATABLE RESTRAINTS (SIR) 8B – 7
DAEWOO M-150 BL2
COMPONENT LOCATOR
SIR COMPONENT
(Left–Hand Drive Shown, Right–Hand Drive Similar)
D110B401
1. Driver Airbag Module
2. Passenger Airbag Module
3. Clock Spring4. Sensing and Diagnostic Module (SDM)
5. Wiring Harness
Page 835 of 1184

8B–8 SUPPLEMENTAL INFLATABLE RESTRAINTS (SIR)
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURES
D110B009A
BULB CHECK
As soon as the operating voltage is applied to the sens-
ing and diagnostic module (SDM) ignition input, the
SDM activates the warning lamp for a bulb check.
The SDM turns the lamp ON for 4 seconds, and then the
SDM turns the lamp OFF.
During the bulb check, the SDM is not ready to detect a
crash or deploy the supplemental inflatable restraints.
FAULT INDICATION
The sensing and diagnostic module records the sys-
tem’s faults in two categories:
Current faults and the fault code appears “Axx” on the
scan tool display.
Historic faults, which are those that were detected in
the past, but are no longer active. And the fault code
appears “Sxx” on the scan tool display.
The warning lamp:
Indicates a fault as soon as it occurs.
Stays ON, even if a fault is no longer active.A scan tool connected to the data link connector (DLC):
Reveals the fault codes.
Receives serial data transmission through the termi-
nal J (13) of the DLC.
Receives ground through the terminal A (4) of the
DLC.
CLEARING FAULT CODES
When the sensing and diagnostic module (SDM) re-
ceives the CODE ERASE command from the scan tool,
the SDM:
Clears the entire fault memory.
Turns OFF the warning lamp.
Resets for fault detection.
External Fault
Service personnel can reset the SDM and turn OFF the
warning lamp if the fault is an external fault.
Internal Fault
An internal fault of the SDM or a CRASH RECORDED
fault code cannot be reset.
In the case of an internal fault of the SDM or a CRASH
RECORDED fault code, the SDM must be replaced.
Voltage-Low Fault
The SDM will turn OFF the VOLTAGE LOW fault as
soon as the voltage recovers.
MICROPROCESSOR –
INDEPENDENT LAMP ACTIVATION
If the sensing and diagnostic module (SDM) electrical
connector is not properly attached, the SDM cannot
function and cannot control the warning lamp.
If this fault is present, the warning lamp will operate in-
dependently from the SDM through the use of shorting
bars that are built into the SDM connector.
Page 836 of 1184
SUPPLEMENTAL INFLATABLE RESTRAINTS (SIR) 8B–9
DAEWOO M-150 BL2
BLANK
Page 837 of 1184

8B–10 SUPPLEMENTAL INFLATABLE RESTRAINTS (SIR)
DAEWOO M-150 BL2
SYSTEM CHECK
D1AB301B
Caution: Use only the scan tool to check the airbag
modules and the sensing and diagnostic module
(SDM). Never measure the resistance of an airbag
module with an ohmmeter. An ohmmeter’s battery
can deploy the airbag and cause injury.
Caution: Before testing, disconnect the negative
battery cable. Wait 1 minute for the SDM capacitor
to discharge. The capacitor supplies reserve power
to deploy the airbags, even if the battery is discon-
nected. Unintentional deployment of the airbags
can cause injury.Caution: Do not attempt to repair the supplemental
inflatable restraints (SIR) wiring harness. An SIR re-
pair can create a high-resistance connection which
can keep the airbags from deploying when needed,
resulting in injury.
Circuit Description
When the ignition switch is turned ON, the SDM is able
to send serial data from the terminal 9 of the SDM to the
terminal J (13) of the assembly line diagnostic link.
Diagnostic System Check
Step Action Value(s) Yes No
1
1. Turn the ignition ON.
2. Check the warning lamp.
Does the warning lamp turn off after 4 seconds?
–
System OK
Go to Step 2
2
1. Connect the scan tool cable to the DLC.
2. Connect the scan tool power cable to the cigar
lighter socket.
3. Select the airbag main menu on the scan tool.
4. Select “Fail Code View & Clear “ from the
displayed menu of the diagnostic test codes
(DTC).
Are there any active fault codes?
–
Go to the DTC
table for the
fault indicated
Go to Step 3
Page 838 of 1184