Opel Frontera UBS. Manual - part 2913

SUPPLEMENTAL RESTRAINT SYSTEM

9J–5

1. Energy Reserve — The SDM maintains 24–Volt Loop

Reserve (24VLR) energy supply to provide
deployment energy when ignition voltage is lost in a
frontal crash.

2. Frontal Crash Detection — The SDM monitors

vehicle velocity changes to detect frontal crashes
which are severe enough to warrant deployment.

3. Air Bag Deployment — When a frontal crash of

sufficient force is detected, the SDM will cause
enough current to flow through the air bag assembly
to deploy the air bag.

4. Malfunction Detection — The SDM performs

diagnostic monitoring of SRS electrical components
and sets a diagnostic trouble code when a
malfunction is detected.

5. Frontal Crash Recording — The SDM records

information regarding SRS status during frontal
crash.

6. Malfunction Diagnosis — The SDM displays SRS

diagnostic trouble codes and system status
information through the use of a scan tool.

7. Driver Notification — The SDM warns the vehicle

driver of SRS malfunctions by controlling the “Air
Bag” warning lamp.

The SDM is connected to the SRS wiring harness by a
24–pin connector.  This harness connector uses a
shorting clip across certain terminals in the contact area.
This shorting clip connects the “AIR BAG” warning lamp
to ground when the SDM harness connector is
disconnected or CPA (Connector Position Assurance) is
not inserted even if completely connected.  This will
cause the “AIR BAG” warning lamp to come “ON” steady
whenever the ignition switch is at the ON or START
positions with the SDM disconnected.

827RW044

Legend

(1) SDM
(2) SRS Harness
(3) Connector Position Assurance

“Air Bag” Warning Lamp

Ignition voltage is applied to the “AIR BAG” warning lamp
when the ignition switch is at the ON or START positions.
The SDM controls the lamp by providing ground with a
lamp driver.  The “AIR BAG” warning lamp is used in the
SRS to do the following:

1. Verify lamp and SDM operation by turn on 3.5

seconds and then turns “OFF” when the ignition
switch is first turned “ON”.

2. Warn the vehicle driver of SRS electrical system

malfunctions which could potentially affect the
operation of the SRS.  These malfunctions could
result in nondeployment in case of a frontal crash or
deployment for conditions less severe than intended.

The “AIR BAG ” warning lamp is the key to driver
notification of SRS malfunctions.  For proper lamp
operation, refer to the “SRS Diagnostic System Check” in
this section.

821RW037

SRS Coil Assembly

The SRS coil assembly consists of two current carrying
coils.  This is attached to the steering column and allow
rotation of the steering wheel while maintaining
continuous contact of the driver deployment loop to the
driver air bag assembly.
There is a shorting clip on the yellow 2–pin connector near
the base of steering column which connects the SRS coil
to the SRS wiring harness.
The shorting clip shorts to the SRS coil and driver air bag
assembly when the yellow 2–pin connector is
disconnected.  The circuit to the driver air bag assembly is
shorted in this way to help prevent unwanted deployment
of the air bag when servicing the steering column or other
SRS components.

SUPPLEMENTAL RESTRAINT SYSTEM

9J–6

825RS017

Air Bag Assemblies

The air bag assembly consist of an inflatable air bag
assembly and an inflator (a canister of gas–generating
material and an initiating device).  When the vehicle is in a
frontal crash of sufficient force.
The SDM causes current flow through the deployment
loops.  Current passing through the inflator ignites the
material in the air bag assembly.  The gas produced from
this reaction rapidly inflates the air bag assembly.
There is a shorting clip on the driver air bag assembly
connector which connects the SRS coil assembly.  The
shorting clip shorts across the driver air bag assembly
circuits when driver air bag assembly connector is
disconnected.
The circuit to the driver air bag assembly is shorted in this
way to help prevent unwanted deployment of the air bag
when servicing the driver air bag assembly, the steering
column or other SRS components.

827RS008

There is a shorting clip on the passenger air bag
assembly connector which connects to the SRS harness.

The shorting clip shorts across the passenger air bag
assembly circuit when the passenger air bag assembly
connector is disconnected.  The circuit to the passenger
air bag assembly is shorted in this way to help prevent
unwanted deployment of the air bag when servicing the
passenger air bag assembly, the instrument panel or
other SRS components.

827RS001

Seat Belt with Pretensioner (If so
equipped)

The seat belt comprises a seat belt and a cylinder (a
cylinder filled with powder and an ignition device).  In
cases of frontal collision which cause a shock exceeding
a specified level, the controller lets current flow to the
inflation circuit.  The current ignites the cylinder of the seat
belt, producing gas.  The gas helps tighten the seat belt to
restrain firmly the driver’s upper half in his seat.

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SUPPLEMENTAL RESTRAINT SYSTEM

9J–7

Steering Column

The steering column absorbs energy and is designed to
compress in a frontal crash to decrease the chance of
injury to the driver.

431RW019

Knee Bolster

The knee bolsters are used to absorb energy to protect
knees and control the forward movement of the vehicle’s
front seat occupants during a frontal crash, by limiting leg
movement.

740RT015

Definitions

Air Bag
An inflatable cloth cushion designed to deploy in certain
frontal crashes.  It supplements the protection offered by
the seat belts by distributing the impact load more evenly
over the vehicle occupant’s head and torso.

Asynchronous
Performed in a nonperiodic fashion, (i.e., no defined time
or interval).

B+
Battery voltage, (B+) The voltage available at the battery
at the time of the indicated measurement.  With the key
“ON” and the engine not running, the system voltage will
likely be between 12 and 12.5 volts.  At idle, the voltage
may be 14 to 16 volts.  The voltage could be as low as 10
volts during engine cranking.

Bulb Check
The SDM will cause the “AIR BAG” warning lamp to turn
on 3.5 seconds and then go “OFF” whenever the ignition
switch transitions to the ON position from any other
ignition switch position and no malfunctions are detected.

“Continuous Monitoring”
Tests performed by the SDM on the SRS every 100
milliseconds while “Ignition 1” voltage is in the normal
operating voltage range at the SDM.

Data Link Connector (DLC)
Formerly “DLC” a connector which allows communication
with an external computer, such as a scan tool.

Datum Line
A base line parallel to the plane of the underbody or frame
from which all vertical measurements originate.

Deploy
To inflate the air bag.

Deployment Loops
The circuits which supply current to the air bag
assemblies to deploy the air bag.

Diagnostic Trouble Code (DTC)
Formerly “Code”, a numerical designator used by the
SDM to indicate specific SRS malfunctions.

Driver Current Source
An output of the SDM which applies current into the driver
air bag assembly circuit during the “Initiator Assembly
Resistance Test”.

Driver Air Bag Assembly
An assembly located in the steering wheel hub consisting
of an inflatable bag, an inflator and an initiator.

EEPROM
Electrically Erasable Programmable Read Only Memory.
Memory which retains its contents when power is
removed from the SDM.

Ignition Cycle
The voltage at the SDM “Ignition 1” inputs, with ignition
switch “ON”, is within the normal operating voltage range
for at least ten seconds before turning ignition switch
“OFF”.

Ignition 1
A battery voltage (B+) circuit which is only powered with
the ignition switch in the ON, or START positions.

Initiator
The electrical component inside the air bag assembly
which, when sufficient current flows, sets off the chemical
reaction that inflates the air bag.

“Initiator Assembly Resistance Test”
Tests performed once each ignition cycle when no
malfunctions are detected during “Turn–ON” or
“Continuous Monitoring”. This test checks for the correct
SDM configuration for the vehicle, shorts to “Ignition 1” in

SUPPLEMENTAL RESTRAINT SYSTEM

9J–8

the deployment loops, high resistance or opens in the
“Driver Side High”, “Driver Side Low”, “Passenger Side
High” and “Passenger Side Low” circuits and measures
the resistance of the inflator assembly consisting of 1)
Initiators, 2) SRS coil assembly (driver side only), 3)
Connectors and associated wiring.

Normal Operating Voltage Range
The voltage measured between the SDM “Ignition 1”
terminals and “Ground” terminals is between 9 and 16
volts.

Passenger Current Source
An output of the SDM which applies current into the
passenger air bag assembly circuit during the “Initiator
Assembly Resistance Test”.

Passenger Air Bag Assembly
An assembly located in the right side of the instrument
panel consisting of an inflatable bag, an inflator and an
initiator.

Scan Tool
An external computer used to read diagnostic information
from on–board computers via the data link connector.

SDM
Sensing and Diagnostic Module which provides reserve
energy to the deployment loops, deploys the air bags
when required and performs diagnostic monitoring of all
SRS components.

Serial Data
Information representing the status of the SRS.

SRS
Supplemental Restraint System.

SRS Coil Assembly
An assembly of two current–carrying coils in the driver
deployment loop that allows the rotation of the steering
wheel while maintaining the continuous contact of the
driver deployment loop to the driver air bag assembly.

SRS Wiring Harness
The wires and connectors that electrically connect the
components in the SRS.

“Turn–ON”
Test which the SDM performs on the SRS once during
each ignition cycle immediately after “Ignition 1” voltage
is applied to the SDM and before “Continuous
Monitoring”.

Diagnosis

WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS, DO NOT USE
ELECTRICAL TEST EQUIPMENT SUCH AS A
BATTERY–POWERED OR AC–POWERED
VOLTMETER, OHMMETER, ETC., OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN THAT
SPECIFIED IN THIS MANUAL.  DO NOT USE A
NONPOWERED PROBE–TYPE TESTER.
INSTRUCTIONS IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE PERSONAL
INJURY MAY RESULT.

Diagnostic Trouble Codes

The “SRS Diagnostic System Check” must always be the
starting point of any SRS diagnosis.  The “SRS
Diagnostic System Check” checks for proper “AIR BAG”
warning lamp operation and checks for SRS diagnostic
trouble codes using the scan tool.

1. Current diagnostic trouble codes – Malfunctions that

are presently being detected. Current diagnostic
trouble codes are stored in RAM (Random Access
Memory).

2. History diagnostic trouble codes – All malfunctions

detected since the last time the history memory was
cleared.  History diagnostic trouble codes are stored
in EEPROM.

Scan Tool Diagnostics

A scan tool is used to read current and history diagnostic
trouble codes and to clear all diagnostic trouble codes
after a repair is completed.  The scan tool must be
updated to communicate with the SRS through a
replaceable cartridge before it can be used for SRS
diagnostics.  To use the scan tool, connect it to the data
link connector and turn the ignition switch “ON”. The scan
tool reads serial data from the SDM “Serial Data” line
terminal “24” to the data link connector terminal “9”.

Use Of Special Tools

WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS, DO NOT USE
ELECTRICAL TEST EQUIPMENT SUCH AS A
BATTERY–POWERED OR AC–POWERED
VOLTMETER, OHMMETER, ETC, OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN THAT
SPECIFIED IN THIS MANUAL.  DO NOT USE A NON
POWERED PROBE–TYPE TESTER. INSTRUCTIONS
IN THIS MANUAL MUST BE FOLLOWED
CAREFULLY, OTHERWISE PERSONAL INJURY MAY
RESULT.  YOU SHOULD BE FAMILIAR WITH THE
TOOLS LISTED IN THIS SECTION UNDER THE
HANDLING SRS SPECIAL TOOLS.

You should be able to measure voltage and resistance.
You should be familiar with proper use of a scan tool such
as the Tech 2 Diagnostic Computer, SRS
Driver/Passenger Load Tool 5–8840–2421–0, Connector
Test Adapter Kit 5–8840–0385–0, and the DVM (Digital
Multimeter) 5–8840–0285–0.