1998 ISUZU TROOPER check oil

SUPPLEMENTAL RESTRAINT SYSTEM9J±5
1. Energy Reserve Ð 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 Ð The SDM monitors
vehicle velocity changes to detect frontal crashes
which are severe enough to warrant deployment.
3. Air Bag Deployment Ð 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 Ð The SDM performs
diagnostic monitoring of SRS electrical components
and sets a diagnostic trouble code when a
malfunction is detected.
5. Frontal Crash Recording Ð The SDM records
information regarding SRS status during frontal
crash.
6. Malfunction Diagnosis Ð The SDM displays SRS
diagnostic trouble codes and system status
information through the use of a scan tool.
7. Driver Notification Ð The SDM warns the vehicle
driver of SRS malfunctions by controlling the ªAir
Bagº 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 ªAIR BAGº 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 ªAIR BAGº warning lamp to come ªONº 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
ªAir Bagº Warning Lamp
Ignition voltage is applied to the ªAIR BAGº 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 ªAIR BAGº 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 ªOFFº when the ignition
switch is first turned ªONº.
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 ªAIR BAG º warning lamp is the key to driver
notification of SRS malfunctions. For proper lamp
operation, refer to the ªSRS Diagnostic System Checkº 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±8
the deployment loops, high resistance or opens in the
ªDriver Side Highº, ªDriver Side Lowº, ªPassenger Side
Highº and ªPassenger Side Lowº 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 ªIgnition 1º
terminals and ªGroundº 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 ªInitiator
Assembly Resistance Testº.
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.
ªTurn±ONº
Test which the SDM performs on the SRS once during
each ignition cycle immediately after ªIgnition 1º voltage
is applied to the SDM and before ªContinuous
Monitoringº.
Diagnosis
WARNING: T O AV O I D D E P L O Y M E N T W H E N
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 ªSRS Diagnostic System Checkº must always be the
starting point of any SRS diagnosis. The ªSRS
Diagnostic System Checkº checks for proper ªAIR BAGº
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 ªONº. The scan
tool reads serial data from the SDM ªSerial Dataº line
terminal ª24º to the data link connector terminal ª9º.
Use Of Special Tools
WARNING: T O AV O I D D E P L O Y M E N T W H E N
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.

SUPPLEMENTAL RESTRAINT SYSTEM 9J±10
Accident With Deployment ± Component
Replacement And Inspections
Certain SRS components must be replaced or inspected
for damage after a frontal crash involving air bag
deployment. Those components are:

Air bag assembly

SDM
CAUTION: Refer to ªSDM Replacement Guidelinesº
below for important information on SDM
replacement in both deployment and non
deployment crashes.

SRS coil assembly Ð Inspect wiring and connector
for any signs of scorching, melting, or damage due to
excessive heat. Replace if damaged. Refer to
section ªSRS Coil Assemblyº in this manual.
Accident With or Without Deployment ±
Component Inspection
Certain SRS system components and rotation parts must
be inspected after any crash, whether the air bag
deployed or not. Those components are:

Steering column Ð Refer to Inspection Required
ªAfter an Accidentº in this manual.

Knee bolsters and mounting points Ð Inspect for any
distortion, bending, cracking, or other damage.

I/P steering column reinforcement plate Ð Inspect for
any distortion, bending, cracking, or other damage.

I/P braces Ð Inspect for any distortion, bending,
cracking, or other damage.

Seat belts and mounting points Ð Refer to ªSeat
Beltsº in Section ªSeat Beltº of this workshop manual.
SDM Replacement Guidelines
SDM replacement policy requires replacement of SDM,
after crash involving air bag deployment when ªSRS
Warning Lampº turn ªONº, ªSRS Diagnosisº should be
done according to Section ªRestraint Control System.º
If accident without deployment air bag, it is not necessary
replacement of SDM when do not indicate to replace the
SDM by scan tool after SRS system check.
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
ªpigtailº components are the driver air bag assembly, the
passenger air bag assembly, and the SRS coil assembly.
On±Vehicle Service
Service Precaution
WARNING: WHEN PERFORMING SERVICE ON OR
AROUND SRS COMPONENTS OR SRS WIRING,
FOLLOW THE PROCEDURES LISTED BELOW TO
TEMPORARILY DISABLE THE SRS. FAILURE TO
FOLLOW PROCEDURES COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY OR OTHERWISE UNNEEDED SRS REPAIRS.
The SDM in Driver±Passenger SRS can maintain
sufficient voltage to cause a deployment for up to 15
seconds after the ignition switch is turned ªOFF,º the
battery is disconnected, or the fuse powering the SDM is
removed.
Many of the service procedures require removal of the
ªC±21º fuse, and disconnection of the air bag assembly
from the deployment loop to avoid an accidental
deployment. If the air bag assembly is disconnected from
the deployment loop as noted in the ªDisabling the SRSº
procedure that follows, service can begin immediately
without waiting for the 15 second time period to expire.
Disabling The SRS
Removal
Turn the ignition switch to ªLOCKº and remove key.
1. Remove SRS fuse C±21, from left dash side lower
fuse block or disconnect battery.
2. Disconnect yellow 2±pin connector at the base of
steering column.
3. Remove glove box assembly, refer to ªPassenger Air
Bag Assembly Replacementº in this manual.
4. Disconnect yellow 2±pin connector behind the glove
box assembly.
CAUTION: W i t h t h e ª C±21º fuse removed and
ignition switch ªONº, the ªAIR BAGº warning lamp
will be ªONº. This is normal operation and does not
indicate an SRS malfunction.
Enabling The SRS
Installation
CAUTION: Never use the air bag assembly from
another vehicle. Use only the air bag assembly for
Trooper.
Turn ignition switch to ªLOCKº and remove key.
1. Connect yellow 2±pin connector passenger air bag
assembly.
2. Install glove box assembly. Refer to ªPassenger air
bag assembly replacementº in this manual.
3. Connect yellow 2±pin connector at the base of
steering column.
4. Install ªAIR BAGº fuse C±21 to left dash side lower
fuse block or connect battery.
Turn ignition switch to ªONº and verify that the ªAIR BAGº
warning lamp turn on 3.5 seconds and then turns ªOFF.º If
it does not operate as described, perform the ªSRS
Diagnostic System Checkº in this manual.

SUPPLEMENTAL RESTRAINT SYSTEM 9J±30
Service Precautions for SRS
Component Service
CAUTION: When fasteners are removed, always
reinstall them at the same location from which they
were removed. If a fastener needs to be replaced, use
the correct part number fastener for that application.
If the correct part number fastener is not available, a
fastener of equal size and strength (or stronger) may
be used. fasteners that are not reused, and those
requiring thread locking compound will be called
out. The correct torque value must be used when
installing fasteners that require it. If the above
conditions are not followed, parts or system damage
could result.
WARNING: WHEN PERFORMING SERVICE ON OR
AROUND SRS COMPONENTS OR SRS WIRING,
FOLLOW THE PROCEDURES LISTED BELOW TO
TEMPORARILY DISABLE THE SRS. FAILURE TO
FOLLOW PROCEDURES COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY OR OTHERWISE UNNEEDED SRS REPAIRS.
The SDM in Driver±Passenger SRS can maintain
sufficient voltage to cause a deployment for up to 15
seconds after the ignition switch is turned ªOFF,º the
battery is disconnected, or the fuse powering the SDM is
removed.
Many of the service procedures require removal of the
ªC±21º fuse, and disconnection of the air bag assembly
from the deployment loop to avoid an accidental
deployment. If the air bag assembly is disconnected from
the deployment loop as noted in the ªDisabling the SRSº
procedure that follows, service can begin immediately
without waiting for the 15 second time period to expire.
Disabling The SRS
Removal
Turn the ignition switch to ªOFFº and turn the steering
wheel so that the vehicle's wheels are pointing straight
ahead.
1. Remove SRS fuse ªC±21º from left dash side lower
fuse block or disconnect battery.
2. Disconnect yellow 2±pin connector at the base of
steering column.
3. Remove glove box assembly; Refer to ªPassenger air
bag assembly replacementº in this section.
4. Disconnect passenger air bag assembly yellow 2±pin
connector behind the glove box assembly.
CAUTION: W i t h t h e ª C±21º fuse removed and
ignition switch ªON,º the ªAIR BAGº warning lamp
will be ªON.º This is normal operation and does not
indicate an SRS malfunction.
Enabling The SRS
Installation
Turn ignition switch to ªLOCKº and remove key.
1. Connect yellow 2±pin connector passenger air bag
assembly.2. Install glove box assembly. Refer to ªPassenger Air
Bag Assembly Replacementº in this section.
3. Connect yellow 2±pin connector at the base of the
steering column.
4. Install ªAIR BAGº fuse ªC±21º to left dash side lower
fuse block or connect battery.
Turn ignition switch to ªONº and verify that the ªAIR BAGº
warning lamp turn on 3.5 seconds and then turns ªOFF.º If
it does not operate as described, perform the ªSRS
Diagnostic System Checkº in this section.
Handling / Installation / Diagnosis
1. Air bag assembly should not be subjected to
temperatures above 93
C (200
F).
2. Air bag assembly, and SDM should not be used if they
have been dropped from a height of 100 centimeters
(3.28 feet) or more.
3. When a SDM is replaced, it must be oriented with the
arrow on the SDM pointing toward the front of the
vehicle. It is very important for the SDM to be located
flat on the mounting surface, parallel to the vehicle
datum line. It is important that the SDM mounting
surface is free of any dirt or other foreign material.
4. Do not apply power to the SRS unless all components
are connected or a diagnostic chart requests it, as
this will set a diagnostic trouble code.
5. The ªSRS Diagnostic System Checkº must be the
starting point of any SRS diagnostics. The ªSRS
Diagnostic System Checkº will verify proper ªAIR
BAGº warning lamp operation and will lead you to the
correct chart to diagnose any SRS malfunctions.
Bypassing these procedures may result in extended
diagnostic time, incorrect diagnosis, and incorrect
parts replacements.
Inspections Required After An Accident
CAUTION: C e r t a i n S R S c o mponents must be
replaced after a frontal crash involving air bag
deployment.
In all types of accidents regardless of ªAir Bagº
deployment, visually inspect all of the following
components and replace as required:
Ð Driver air bag assembly
Ð Passenger air bag assembly
Ð Driver pretensioner assembly
Ð Passenger pretensioner assembly
Ð Steering wheel
Ð SRS coil assembly
Ð Steering column
Ð Knee bolster and instrument panel mounting
attachments
Ð Driver seat and belt
Ð Passenger seat and belt
Ð SDM
SDM always should be checked according to ªSDM
Replacement Guidelines.º

SUPPLEMENTAL RESTRAINT SYSTEM9J±31
CAUTION: Refer to ªSDM Replacement Guidelinesº
below for important information on SDM
replacement in both deployment and
non±deployment crashes.
Inspect SRS coil assembly wiring and steering wheel for
any sign of scorching, melting, or damage due to
excessive heat. If coil assembly wire or steering wheel is
damaged, replace them. The steering column and wheel
must be dimensionally checked to determine if they are
damaged. Refer to steering wheel of in this manual.
Never use SRS parts from another vehicle. This does not
include remanufactured parts purchased from an
authorized Isuzu Retailer; they may be used for SRS
repairs.
Do not attempt to repair the SDM, the SRS harness, the
SRS coil assembly, the air bag assembly, the steering
wheel, or the steering column. Service of these items is
replacement only. Verify replacement part numbers.
CAUTION: P r o p e r o p e r a t i o n o f t h e S D M a n d
supplemental restraint system (SRS) requires that
any repairs to the vehicle structure return it to its
original production configuration.
SRS Connectors
CAUTION:The special yellow color connectors are
used for supplemental restraint system air bag circuit.
When removing the oable harnese, do not pull the cables
otherwile, cable disconnection may occur. When connect
the SRS connector, insert the connector completely.
Imperfect locking may cause malfunction of SRS circuit.
Removal
To remove the connector, hold the cover insulator (1) and
pull it. The cover insulator slides and lock will be released.
Do not hold the socket insulator (2).
827RW028

9J1±9
RESTRAINT CONTROL SYSTEM
Chart B ªAIR BAGº warning lamp comes ªONº Steady
StepActionYe sNo
11. When measurements are requested in this chart use
5±8840±0285±0 DVM with correct terminal adapter from
5±8840±0385±0.
2. Ignition switch ªOFF.º
3. Connect scan tool to data link connector, follow directions as
given in the scan tool instruction MANUAL.
4. Ignition switch ªON.º
5. Request SRS diagnostic trouble code display.
Dose scan tool indicate ªNo Data Receivedº?
Go to Step 2Go to Step 3
21. Ignition switch ªOFFº.
2. Inspect SDM harness connector connection to SDM.
Is it securely connected to the SDM?
Ignition switch
ªOFFº
Replace SDM
Go to Step 5
Connect SDM
securely to
de±activate
shorting clip in
SDM harness
connector
Go to Step 5
3Using scan tool, request SRS data list.
Is ªignitionº less than 9 volts?
Go to Step 4
Ignition switch
ªOFFº
Replace SDM
Go to Step 5
41. Ignition switch ªOFF.º
2. Disconnect SRS coil and passenger air bag assemblies.
yellow 2±pin connector located at base of steering column and
behind the glove box assembly.
Disconnect SDM.
3. Disconnect the connector of ªSRS Warning Lampº of
instrument cluster.
4. Measure resistance from SDM harness connector terminal ª7º
to ground ª6º.
Does 5±8840±0285±0 display ªOLº (Infinite)?
Go to Chart A
Replace SRS
harness
Go to Step 5
5Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished?Repeat the ªSRS
Diagnostic
System Checkº
Go to Step 5

9J1±11
RESTRAINT CONTROL SYSTEM
Chart C ªAIR BAGº Warning Lamp Does Not Come ªONº Steady
StepActionYe sNo
11. When measurements are requested in this chart,use
5±8840±0285±0 DVM with correct terminal adapter from
5±8840±0385±0.
2. Ignition switch ªOFF.º
3. Remove and inspect ªC±10º fuse (meter) to the ªAIR BAGº
warning lamp.
Is fuse good?
Go to Step 2Go to Step 7
21. Ignition switch ªOFF.º
2. Disconnect SRS coil and passenger air bag assemblies.
Yellow 2±pin connector located at base of steering column and
behind the glove box assembly.
3. Disconnect SDM.
4. Ignition switch ªON.º
5. Measure voltage on SDM harness connector from terminal ª7º
to terminal ª6º (ground).
Is system voltage present on terminal ª7º?
Go to Step 4Go to Step 3
31. Ignition switch ªOFF.º
2. Remove instrument meter cluster.
3. Check for proper connection to instrument cluster at
IB04±WHT/RED terminal.
4. If ok, then remove and inspect ªAIR BAGº bulb.
Is bulb good?
Go to Step 5
Replace bulb
Go to Step 6
41. Ignition switch ªOFF.º
2. Disconnect instrument meter cluster harness connector.
3. Ignition switch ªON.º
4. Measure voltage on SDM harness connector from terminal ª7º
to terminal ª6º (GROUND).
Is voltage 1 volt or less?
Go to Chart A
Replace SRS
harness
Go to Step 6
51. Install bulb.
2. Measure resistance from instrument meter cluster harness
connector IB04±WHT/RED terminal to SDM harness
connector terminal ª7º.
Is resistance 5.0 ohms or less?Service
instrument meter
cluster
Install instrument
meter cluster
Go to Step 6
Replace SRS
harness
Go to Step 6
6Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished?Repeat the ªSRS
Diagnostic
System Checkº
Go to Step 6
7Perform chart C.
Was this step finished?
Go to Step 8Go to Step 1
81. Replace ªC±10º fuse.
2. Ignition switch ªONº wait 10 Seconds then ignition switch ªOff.º
3. Remove and inspect ªC±10º fuse.
Is fuse good?
Install ªC±10º
fuse
Go to Step 10
Go to Step 9

RESTRAINT CONTROL SYSTEM 9J1±12
Chart C ªAIR BAGº Warning Lamp Does Not Come ªONº Steady (Cont'd)
StepNo Ye s Action
91. Disconnect SRS coil and passenger air bag assemblies.
Yellow 2±pin connectors located at base of steering column
and behind the glove box assembly.
2. Disconnect SDM.
3. Replace ªC±10º fuse.
4. Ignition switch ªONº wait 10 seconds.
5. Ignition switch ªOFFº.
6. Remove and inspection ªC±10º fuse.
Is fuse good?
InstallªC±10º fuse
Go to Chart A
Replace SRS
harness
Replace ªC±10º
fuse
Go to Step 10
10Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished?Repeat the ªSRS
Diagnostic
System Checkº
Go to Step 10