1995 ISUZU TROOPER Workshop Manual

PASSENGER CURRENT SOURCE -An output of the
DERM which injects current into the passenger inflator
module circuit during the
~Initiator Assembly Resistance
'--"" Test."
PASSENGER INFLATOR MODULE -An assembly
located in the right side of the 1/P consisting of an
inflatable bag, an inflator and an initiator.
SCAN TOOL -An off-board computer used to read
diagnostic information from on-board computers via the
data
link connector.
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 inflator module.
SRS WIRING HARNESS-The wires and connectors
that electrically connect the components in the
SRS.
1 Supplemental Restraint System 9J-9
"10 MINUTE LOOP TEST' -Portions of the "Initiator
Assembly Resistance Test" are repeated every ten
minutes during an ignition cycle. These are the check for
shorts to
"Ignition 1" in the deployment loops and the
check for an open discriminating sensor interconnect
circuit.
''TURN-ON" -Test which the DERM performs on the
SRS once during each ignition cycle immediately after
"Ignition 1" voltage is applied to the DERM and before
"Continuous Monitoring."
36VLR-The 36-volt loop reserve energy supplies from
the DERM which provide deployment power when
vehicle voltage is
low or lost in a frontal crash.
36 VLR DELAY
-Changing of the 36 VLR power supplies
is
inhibited briefly during "Turn-ON." This allows
detection of certain malfunctions related to "Ignition 1"
voltage which cannot be tested with 36 volts present.

9J-10 Supplemental Restraint System
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
NON-POWERED 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 DERM
"Serial Data" line
terminal
"A11" to the data link connector terminal "2".
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 HEADING 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 1 Diagnostic Computer TK-O, SRS
Driver/Passenger Load Tool J-41433, Connector Test
Adapter Kit J-35616-A, and the DVM(Digital
Multimeter)J-39200.
•

Supplemental Restraint System 9J-11
SRS CONNECTOR BODY FACE VIEWS
DUAL POLE ARMING SENSOR
DERM
DRIVER INFLATOR PASSENGER INFLATOR
FORWARD DISCRIMINATING SENSOR-LH FORWARD DISCRIMINATING SENSOR-RH

9J-12 Supplemental Restraint System

REPAIRS AND INSPECTIONS REQUIRED AFTER AN
ACCIDENT
NOTE
• If
any SRS components are damaged, they must be
replaced. If SRS component mounting points are
damaged, they must be
replaced.
•
Never use SRS parts from another vehicle. This
does not
include remanufactured parts purchased
from an authorized
dealer; they may be used for SRS
repairs.
• Do not attempt to service discriminating sensors, the
dual pole arming sensor, the DERM, the SRS coil
assembly,
or the inflator modules. Service of these
items is by
replacement only.
•
Verify the part number of replacement inflator
modules.
CAUTION: PROPER OPERATION OF THE
SENSORS AND SUPPLEMENTAL RESTRAINT
SYSTEM (SRS) REQUIRES THAT ANY REPAIRS TO
THE VEHICLE STRUCTURE RETURN IT TO THE
ORIGINAL PRODUCTION CONFIGURATION.
DEPLOYMENT REQUIRES, AT A MINIMUM,
REPLACEMENT OF THE SENSORS, THE INFLATOR
MODULE,
AND DIMENSIONAL INSPECTION OF THE
STEERING COLUMN. ANY VISIBLE DAMAGE TO
THE DERM MOUNTING BRACKET(S) REQUIRES
REPLACEMENT, SENSORS MUST BE REPLACED,
AND THE
STEERING COLUMN MUST BE
DIMENSIONALLY INSPECTED, WHETHER
DEPLOYMENT
OCCURRED OR NOT.
ACCIDENT WITH DEPLOYMENT-COMPONENT
REPLACEMENT AND
INSPECTIONS
Certain SRS components must be replaced for damage
after a
frontal crash involving air bag deployment. Those
components are:
• Inflator modules.
• All
sensors. It is include among the Dual pole Arming
Sensor.
CAUTION
•
Refer to "Sensor Replacement Guidelines"
below for Important Information on sensor
replacement In both deployment and
non-deployment crashes.
• SRS coil assembly, Inspect wiring and connector for
any signs of scorching,
melting, or damage due to
excessive heat.
Replace if damaged. Refer to this in
section
3.
ACCIDENT WITH OR WITHOUT DEPLOYMENT­
COMPONENT INSPECTIONS
Certain SRS and restraint system components must be
inspected after any crash, whether the air bag
deployed
or not. Those components are:
• Steering column-Dimensionally inspect per
"Checking Steering Column for Accident Damage" in
section 3.
• Sensors, if in the area of accident damage. If with
deployment, All sensors must be replaced.
CAUTION
•
Refer to "Sensor Replacement Guidelines"
below for Important information on sensor
replacement in both deployment and
non-deployment crashes.
• Knee bolsters and mounting points-Inspect for any
distortion, bending, cracking, or other damage.
• 1/P steering column reinforcement plate-Inspect for
any distortion, bending, cracking, or other damage.
• liP braces-Inspect for any distortion, bending,
cracking, or other damage.
~
• Seat belts and mounting points-Refer to "Seat Belts"
in SECTION 10.
SENSOR REPLACEMENT GUIDELINES
SRS sensor replacement policy requires replacement of
the all sensors, after crash Involving Air Bag
Deployment.
WIRING DAMAGE
If any SRS wire harness is damaged, it should be
replaced. Don't repair SRS HARNESS. It is replace only.
SRS CONNECTOR {PLASTIC BODY AND
TERMINAL METAL PIN) DAMAGE
If any connector or terminal in the SRS wire harness
(except
pigtails) is damaged, it should be replaced.
SRS WIRE PIGTAIL DAMAGE
If the wiring pigtail (a wire or wires attached directly to the
device,
not by a connector)is damaged, the entire
component(with pigtail)must be replaced. Examples of
"pigtail" components are the driver inflator module, the
passenger
inflator module, the discriminating sensors,
the
dual pole arming sensor and the SRS coil assembly. ~
SRS WIRE DAMAGE
If any wire except the pigtail is damaged, the wire should
be replaced.
Ill