air condition ISUZU TROOPER 1995 Workshop Manual

9B-36 CRUISE CONTROL
B REMOVAL (FIG. 98-21)
Preparation: Disconnect the battery ground cable.
Vacuum hose
Fig. 98-21
1. Pump
• Disconnect the connector.
• Disconnect the vacuum hose.
• Remove the pump fixing screws.
2. Actuator
• Disconnect the inner cables of the actuator at
the accelerator
pedal.
•
Remove the outer cable clips.
• Remove the actuator fixing screws.
E) INSTALLATION
To install, follow the removal steps in the reverse
order, noting
the following point.
1. Take care not to bend the cable excessively.
BRAKE SWITCH
~ INSPECTION
2 1
Push rod
~
~'
s ~ 1
Stoplight Depress brake pedal
(oush rod out)
Cruise Depress brake
pedal
control (push rod in)
Fig. 98-22
I B-131
2 3
o--o
4
~1. Check the installation condition of the brake
switch.
• Refer to the brake switch of "STOPLIGHT
AND REAR DEFOGGER" section in this
manual.
2. Check the continuity between the switch con­
nector terminals. (Fig. 98-22)
3. Check to see if the push rod operates
smoothly. Adjust, repair
or replace the brake switch
when the result
of inspection is found abnor­
mal.
B REMOVAL AND INSTALLATION
1·++·1 Refer to the brake switch of "STOPLIGHT AND
REAR DEFOGGER" section in this manual.
CLUTCH SWITCH
~INSPECTION
I B-161 1
rnll2a-~~
~ s 1 2
Release clutch pedal 0 ~ ~
(Push rod in)
Depress
clutch pedal
~1.
(Push rod out)
Fig. 98-23
Check the installation
condition of the clutch
switch.
• Refer to the clutch switch of "METER AND
WARNING/INDICATOR LIGHT" section in
this
manual.
2. Check the continuity between the switch con­
nector terminals. (Fig. 98-23)
3. Check to see if the push rod operates
smoothly. Adjust, repair
or replace the clutch switch
when the result of inspection is found abnor­
mal.
B REMOVAL AND INSTALLATION
1••1 Refer to the clutch switch of "METER AND ...-...
WARNING/INDICATOR"
section in this manual. ,...........

Supplemental Restraint System 9J-1
SECTION 9J
SUPPLEMENTAL RESTRAINT SYSTEM
(SRS)
WARNING: THIS VEHICLE IS EQUIPPED WITH A SUPPLEMENTAL INFLATABLE RESTRAINT SYSTEM (SRS).
REFER TO WARNING IN THIS SECTION UNDER "ON-VEHICLE SERVICE" AND THE SRS COMPONENT AND
WIRING LOCATION VIEW IN THIS SECTION BEFORE PERFORMING SERVICE ON OR AROUND SRS
COMPONENTS OR WIRING. FAILURE TO FOLLOW WARNING COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR OTHERWISE UNNEEDED SRS REPAIRS.
TABLE OF CONTENTS
SUPPLEMENTAL RESTRAINT SYSTEM
(SRS)
SECTION 1 -INTRODUCTION
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.
GENERAL DESCRIPTION • • • . • . . . . • . . . . . . . . . • . . . . • . . . . . . . . • . . . . . . . . • . . . . • . • . . 3
Restraint Devices • • • • • • • • • • • • • • • • • • • • • • • • • • .. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 3
'W' System Description • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 4
SRS Component and wiring Location View . . . . . . • . . . . . . . . . . . • . . . . • . . . . . . . . . . • • 5
COMPONENT DESCRIPTION • • . .

. .
• . . • . .
.
• . . • . . . . . . . . . . . . . . . . . • . • . • . . . . • . • • . . 6
DERM ••••••••••••••••••\
••••••••••••••••••\
••••••••••••••••••\
•••••••• ~ • • • • • 6
"AIR BAG"Warnlng Lamp • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • .. • • • • • • • • • • • • 6
Dual Pole Arming Sensor • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 6
Discriminating Sensors • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 6
SRS Coli Assembly • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 7
Inflator Modules • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 7
Steering Column • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 7
Knee Bolster • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 7
DEFINITIONS • • . • . . • • • . • • . • • • • • . • . . • • . • . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . • • • • • • 8
DIAGNOSIS • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • . • • • • • . . • • . . . . • • • • • . • • • • • • • • • • • 1 0
Diagnostic Trouble Codes • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 0
Scan Tool Diagnostic • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 0
Use of Special Tools • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 0
SRS CONNECTOR BODY FACE VIEWS . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . • . . . . . 11
REPAIRS AND INSPECTION REQUIRED AFTER AN ACCIDENT . . . . . • . . . . . . . . . . . 12
Accident With Deployment-component Replacement and Inspections • • • • • • • • • • • • • • • • • • 12
Accident With or Without Deployment-Component Inspections • • • • • • • • • • • • • • • • • • • • • • • 12
Sensor Replacement Guideline ••••••••• II • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 12
Wiring Damage ••••••••••••••••••\
••• II • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 12
SRS Conector (Plastic Body and Terminal Metal Pin) Damage • • • • • • • • • • • • • • • • • • • • • • • • • 12

9J-6 Supplemental Restraint System <
COMPONENT DESCRIPTION
DERM
CAUTION: DO NOT OPEN THE DERM CASE FOR
ANY REASON. TOUCHING THE CONNECTOR PINS
OR SOLDERED COMPONENTS MAY CAUSE
ELECTROSTATIC DISCHARGE DAMAGE. REPAIR
OF A MALFUNCTIONING DERM IS BY
REPLACEMENT ONLY.
The DERM is designed to perform the following functions
in the SRS:
1. Energy Reserve- The DERM maintains two 36-Volt
Loop Reserve(36VLR) energy supplies to provide
deployment energy when the vehicle voltage is low
or lost in a frontal crash.
2. Malfunction Detection-The DERM performs
diagnostic monitoring of SRS electrical components.
3. Malfunction Recording- The DERM provides SRS
diagnostic trouble code information through a scan
tool.
4. Driver Notification- The DERM warns the vehicle
driver of SRS malfunctions by controlling the "AIR
BAG"
warning lamp.
5. Frontal Crash Recording- The DERM records the
SRS status during a frontal crash.
The DERM is connected to the
SRS wiring harness by
a
24-way 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 DERM harness connector is
disconnected. This will cause the "AIR BAG" warning
lamp to come "ON" steady whenever the ignition switch
is at the RUN,BULB
TEST or START positions with the
DERM disconnected.
"AIR BAG"WARNING LAMP
Ignition voltage is applied to the "AIR BAG" warning lamp
when the ignition switch is at the RUN,BULB TEST or
START positions. The DERM 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 DERM operation by flashing SEVEN
times 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 non-deployment 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.
DUAL POLE ARMING SENSOR ~
The dual pole arming sensor is a protective switch
located in the high side(power side) of the deployment
loops.
The dual pole arming sensor is calibrated to close
at low level velocity changes(lower than the
discriminating sensors).
This ensures that the
inflator modules are connected
directly to the "36 VLR" outputs of the DERM or "Ignition
1" voltage
when any discriminating sensor closes.
The dual pole arming sensor consists of: a sensing
element, two sets of normally open switch contacts,
diagnostic resistors and diodes. The sensing
element
closes
both sets of switch contacts when the velocity of
the
vehicle changes at a rate indicating a potential need
for
deployment.
Two of the diagnostic resistors are connected in parallel
with the switch contacts. This allows a small amount of
current to
flow through each of the deployment loops
during normal, non-deployment operation. This current
flow results in voltage drops across each component in
the
deployment loops. The DERM monitor these voltage
drops to detect circuit or component malfunctions. There
are two
additional diagnostic resistors within the dual
pole
arming sensor which allow the DERM to monitor the
voltage supplied to the high side ofthe deployment loops.
These monitored voltages are used by the diagnostic
logic of the DERM to make a more precise determination
of the
actual deployment loop malfunction. ~
The diodes within the dual pole arming sensor provide
isolation between the "36VLR" outputs of the DERM and
the
vehicle electrical system "Ignition 1" voltage. The
presence of the diodes prevents a direct continuity
measurement through the
dual pole arming sensor
resistors to
terminals"3","4" or "5".
DISCRIMINATING SENSORS
The discriminating sensors are protective switches wired
in parallel on the low side(ground side) of the deployment
loops.
These sensors are calibrated to close with velocity
changes which are severe enough to warrant
deployment.
The discriminating sensors consist of a sensing element
and normally open switch contacts when the vehicle
velocity changes are severe enough to warrant
deployment.
A diagnostic resistor is connected in parallel with the
switch contacts within the
LH forward discriminating
sensor and
RH forward discriminating sensor. These
parallel resistors supply the ground path for the current
passing through the
deployment loops during normal,
non-deployment operation. This current flow results in
voltage drops across each component within the
deployment loops. The DERM monitors these voltage
drops to detect circuit or component malfunctions.
II

9J-8 Supplemental Restraint System
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 non-periodic
fashion,i.e.no defined time or interval.
B+-Battery voltage, 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 1
0
volts during engine cranking.
BULB
CHECK-The DERM will cause the "AIR BAG"
warning lamp to flash seven times and then go "OFF"
whenever the ignition switch transitions to the RUN
position from any other ignition switch position and no
malfunctions are detected.
"CONTINUOUS MONITORING"-Tests performed by
the DERM on the
SRS every 1 00 milliseconds while
"Ignition
1" voltage is in the normal operating voltage
range at the DERM.
DATA LINK CONNECTOR(DLC)-Formerly "ALDL'', a
connector which allows communication with an
off-board 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 inflator modules to deploy the air bag.
DERM -Diagnostic
energy reserve module which
provides reserve energy to the deployment loops and
performs diagnostic monitoring of
all SRS components.
DIAGNOSTIC TROUBLE CODE(DTC) -Formerly
"Code,"a numerical designator used by the DERM to
indicate specific
SRS malfunctions.
DRIVER CURRENT SOURCE-An output of the DERM
which injects current into the driver inflator module circuit
during the "Initiator Assembly Resistance
Test."
DRIVER INFLATOR
MODULE-An assembly located in
the steering wheel hub consisting of an inflatable air bag,
an inflator and an initiator.
DUAL
POLE ARMING SENSOR-A sensor on the high
side(power side) of the deployment loops that is
calibrated to supply voltage to the inflator modules when
the vehicle velocity changes are severe enough to
warrant arming of the air bags in preparation for
deployment.
EEPROM -Electrically Erasable Programmable Read ~
Only Memory. Memory which retains its contents when
power
is removed from the DERM.
FORWARD LH DISCRIMINATING SENSOR-A sensor
on the low side(ground side) of the deployment loops
which is calibrated to ground the inflator modules when
the vehicle velocity changes are severe enough to
warrant deployment of the air bags.
FORWARD RH DISCRIMINATING SENSOR-A sensor
on the low side(ground side) of the deployment loops
which
is calibrated to ground the inflator modules when
the vehicle velocity changes are severe enough
to
warrant deployment of the air bag.
FORWARD LH SENSOR Eng-Room HARNESS-An
assembly of two correct carrying wires which connects
the Forward
LH discriminating sensor to SRS harness.
FORWARD RH SENSOR Eng-Room HARNESS
JUMPER-An assembly of two current carrying wires
which connects the Forward
RH discriminating sensor to
the
SRS harness.
HIGHER PRIORITY FAULT-Each diagnostic trouble
code
is assigned a priority based on the detectability with
other DTCs present. The priority corresponds to the
detectability of the malfunction ONLY, and does NOT
relate to the criticality of the malfunction with respect to ~
deployment or non-deployment under any given
condition.
IGNITION CYCLE -The voltage at the PERM "Ignition
1"
inputs, with ignition switch "ON," is within the normal
operating voltage range for at least ten seconds before
turning ignition switch
"OFF."
IGNITION1
-A battery voltage(B+)circuit which is only
powered with the ignition switch in the RUN,BULB
TEST,or START positions.
INITIATOR-The electrical component inside the inflator
module 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
DERM configuration for the vehicle, shorts to
"Ignition 1"
in 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 DERM "Ignition 1" ·
terminals and "Ground" terminals is between 7.25 and 16
volts.
•

Suppleme~tralnt System
TABLE OF CONTENTS
SUPPLEMENTAL RESTRAINT SYSTEM
{SRS)
SECTION 2-SYSTEM DIAGNOSIS
9J-27
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.
HOW TO USE THIS SECTION . . . . . . . . • . . . . . . . . . . . • . . . . . . . . . • • • • • • . • . • • . . . . . • • . 30
Diagnostic Procedures • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
Diagnostic Codes • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
How to Read Trouble Codes • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
How to Clear Trouble Codes • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
Scan
Tool Diagnostics • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
Basic Knowledge Required • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
Basic Electrical Circuits • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
"Flash Code"
Diagnostics • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
SYSTEM SCHEMATIC . . • . • . . . . • • • • • • • • . • . . • . . • . • • . • • • . . . • • . . . . . . . • • . . • • • • • • • 31
SRS DIAGNOSTIC SYSTEM CHECK • . • • • . • • . • . . . . . • . • . • . • • • . . . • . • . . • . . . . . . . • . 32
,_.., TABLE A DERM INTEGRITY CHECK • . • • • . . . . . . . . . . • . • • • . • • • . • • . • . . . • . . . . . . . . . 34
TABLE B "AIR BAG" WARNING LAMP COMES "ON" STEADY . . . . . . . . . . . . . . . . • . 36
TABLE C "AIR BAG" WARNING LAMP DOES NOT COME "ON" . . . . . . . . . . . . . . . • . 38
TABLED "AIR BAG" WARNING LAMP DOES NOT COME "ON" STEADY DURING
CRANK .......................................................... .
DTC 14 DUAL POLE ARMING SENSOR DISCONNECTED ..•.••••••.•...........
DTC 15 PASSENGER INITIATOR CIRCUIT RESISTANCE HIGH •.................
DTC 16 PASSENGER INITIATOR CIRCUIT RESISTANCE LOW ...........•...••..
DTC 17 PASSENGER INITIATOR CIRCUIT OPEN ..••.•.......•.•••...•......••.
DTC 18 DISCRIMINATING SENSOR INTERCONNECT OPEN ................... .
DTC
19 PASSENGER INITIATOR CIRCUIT VOLTAGE HIGH •....•.....••.•..•.•..
DTC 21 DRIVER INITIATOR CIRCUIT RESISTANCE HIGH
DTC 22 DRIVER INITIATOR CIRCUIT RESISTANCE LOW ..••••.••.•.••..•.•.•••
DTC 23 DRIVER INITIATOR CIRCUIT VOLTAGE HIGH ........................•.
DTC 24 INITIATOR CIRCUIT VOLTAGE LOW .....••....•..•...•................
DTC 25 INITIATOR CIRCUIT SHORT TO IGNITION .............•.............•..
DTC 26 DRIVER INITIATOR CIRCUIT OPEN •.••........................••..•.••
DTC 28 CURRENT SINK OR SOURCE FAILURE ............................... .
DTC 31 DRIVER LOOP ENERGY RESERVE FEED OPEN ....................... .
40
42
44
46
48
50
52
54
56
58
60
66
70
72
74

9J-30 Supplemental Restraint System (SRS)

HOW TO USE THIS SECTION
DIAGNOSTIC PROCEDURES
WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS, DO NOT USE
ELECTRICAL TEST EQUIPMENT SUCH AS A
BATTERY-POWERED OR AC-POWERED
VOLTMETER, OHMMETR,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.
The diagnostic procedures used in this section are
designed to aid
in finding and repairing SRS problems.
Outlined below
are the steps to find and repair SRS
problems quickly
and effectively. Failure to carefully
follow these procedures may result in extended
diagnostic time, incorrect diagnosis and incorrect parts
replacement.
1. Perform the "SRS Diagnostic System Check". The
"SRS Diagnostic System Check" should always be
the starting point of any SRS diagnostics. The "SRS
Diagnostic System Check" checks for proper "AIR
BAG" indicator operation and checks for SRS trouble
codes using both "Flash Code" and "Scan Tool"
Methods.
2. Refer to the proper diagnostic chart as directed by
the
"SRS Diagnostic System Check". The "SRS
Diagnostic System Check" will lead you to the correct
chart to diagnose any
SRS problems. Bypassing
these procedures may
result in extended diagnostic
time, incorrect diagnosis and incorrect parts
replacement.
3. Repeat the "SRS Diagnostic System Check" after
any repair
or diagnostic procedures have been
performed.Performing the
"SRS Diagnostic System
Check" after all repair or diagnostic procedures will
assure that the repair has been made correctly and
that no other conditions exist.
DIAGNOSTIC CODES
The Diagnostic Energy Reserve Module (DERM)
maintains a history record of all diagnostic codes that
have been detected since the
SRS codes were last
cleared
during service.
1. Current Codes -Faults that are presently detected
this ignition
cycle. Active and Cycle codes are stored
in RAM (Random Access Memory).
2. History
Codes-All faults detected since the last time
the history
fault memory was cleared. History codes
are stored in EEPROM (Electrically Erasable
Programmable Read Only Memory )
HOW TO READ TROUBLE CODES
All codes (Active cycle and history) can be read (or
cleared) by using a Scan Tool (Portable Diagnostic Tool
[PDT)) or equivalent. If a PDT is not available, have the
vehicle serviced by a Saturn Dealer.
HOW TO CLEAR TROUBLE CODES
Trouble codes can only be cleared by using a Scan Tool.
If
a "Scan Tool" is not available, then inform the owner of
the stored codes and suggest that the codes are
cleared
upon the next visit to a ISUZU dealership.
SCAN TOOL DIAGNOSTICS
A Scan Tool can be used to read current and history
codes and to
clear all history codes after a repair is
complete. The scan tool must be updated to
communicate with the
SRS through a replaceable
cartridge or a manufacturer's update before it can be
used for
SRS diagnostics. To use the scan tool, connect
it to the ALDL connector and turn the ignition switch
"ON". Then follow the manufacturer's directions for
communication with the
SRS. The scan tool reads serial
data from the DERM "Serial Data" output (terminal A 11)
to the ALDL connector (terminal M) Via ISUZU
Convertible Connector (terminal 2).
BASIC KNOWLEDGE REQUIRED
Before using this section of the Service Manual, there is
some basic
knowledge which will be required. Without
this knowledge, you
will have trouble using the diagnostic
procedures
in this section. Use care to prevent harm or
unwanted
deployment. Read all cautions in the service
manual and on warning labels attached to SRS
components.
BASIC ELECTRICAL CIRCUITS
You should understand the basic theory of electricity
including series and parallel circuits, and understand the
voltage drops across series resistors. You should know
the meaning of
voltage (volts), current (amps), and
resistance (ohms). You should understand what
happens in a circuit with an open or a shorted wire. You
should be able to read and understand a wiring diagram.
"FLASH CODE" DIAGNOSTICS
"Flash Code" diagnostics are not implemented for SRS
diagnostic on TROOPER(UX)Vehicles.

9J-32 Supplemental Restraint System (SRS)
SRS DIAGNOSTIC SYSTEM CHECK
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.
The diagnostic procedures used in this section are
designed to find and repair
SRS malfunctions. To get the
best results, it is important to use the diagnostic charts
and
follow the sequence listed below:
A. PERFORM THE "SRS DIAGNOSTIC SYSTEM
CHECK."
The "SRS Diagnostic System Check" must be the
starting point of any
SRS diagnostics. The "SRS
Diagnostic System Check" checks for proper "AIR
BAG"
warning lamp operation, the ability of the
DERM to communicate through the
"Serial Data" line
and whether SRS diagnostic trouble codes exist.
B. REFER TO THE PROPER DIAGNOSTIC CHART
AS
DIRECTED BY THE SRS DIAGNOSTIC
SYSTEM CHECK."
The "SRS Diagnostic System Check" 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 replacement.
C. REPEAT THE "SRS DIAGNOSTIC SYSTEM
CHECK" AFTER ANY REPAIR OR DIAGNOSTIC
PROCEDURES HAVE
BEEN PERFORMED.
Performing
the "SRS Diagnostic System Check"
after all repair or diagnostic procedures will ensure
that the repair has been made correctly and that no
other malfunctions exist.
CIRCUIT DESCRIPTION
When the ignition switch is first turned "ON,""Ignition 1"
voltage is applied from the "C-22·C-23" fuse to the
DERM at the
"Ignition 1" input terminals "A9" and "A10"
and from the "C-21" fuse to the DERM at the "Redundant
Indicator Ignition 1" input terminal "B2". The DERM
responds by flashing the
"AIR BAG" warning lamp seven
times while performing tests on the
SRS.When the
engine is being cranked,
"Starter'' voltage is applied from
the
"C-1" fuse to the DERM at the "Crank" input terminal
"B10".The DERM responds by grounding the "SRS
Indicator"
output terminal "B 1" until "Starter" voltage is
removed from the "Crank" input. This results in the "AIR
BAG" warning lamp being "ON" steady during
cranking.After cranking, the DERM will flash the "AIR
BAG"
warning lamp six times and perform tests on the
SRS.
NOTES ON SYSTEM CHECK CHART ~
1. The "AIR BAG" warning lamp should flash seven
times after ignition is first turned
"ON."
2. The "AIR BAG" warning lamp should remain "ON"
steady during cranking.
3. When the "AIR BAG" warning lamp flashes four
times during
"Bulb Check" this indicates a
malfunction
in the redundant lamp driver circuitry.
These malfunctions are diagnosed by
DTC 62 chart.
4. After cranking, the "AIR BAG" warning lamp should
flash six times then go
"OFF."
5. Improper operation of the "AIR BAG" warning lamp
is indicated. This test differentiates a warning lamp
stays
"ON" condition from a warning lamp does not
come
"ON" condition.
6. This test checks for the proper operation of the
"Serial Data" line. This test will also determine
whether history diagnostic trouble codes are stored
and, if so, identify them.
7. This test checks for proper operation of the
"Serial
Data"
line. This test will also identify the stored
diagnostic trouble codes and
whether they are
current or history.
~
DIAGNOSTIC AIDS
The order in which diagnostic trouble codes are
diagnosed is very important. Failure to diagnose the
diagnostic trouble codes in the order specified may result
in extended diagnostic time, incorrect diagnosis and
incorrect parts replacement.

9J-42 Supplemental Restraint System
DTC 14
DUAL
POLE ARMING SENSOR DISCONNECTED
CIRCUIT DESCRIPTION
The DERM monitors the voltage at the "Driver Source
Sense" terminal
"AS", the "Passenger Source Sense"
terminal "AS",
the "Driver Side High" terminal "B9", the
"Passenger
Side High" terminal "A7'', the "Driver Side
Low" terminal
"88" and the "Passenger Side Low"
terminal "87" during the "Continuous Monitoring" tests.
When
all voltages are simultaneously below a specified
value for 500 milliseconds DTC 14 sets.DTC will set
when: The voltages at terminals "A5","A6","B9",
"A7","B8" and "B7'' of the DERM harness connector are
simultaneously below a specified value for 500
milliseconds.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
diagnostic
trouble code.
DTC WILL CLEAR WHEN
The voltage at terminal "A5","A6","B9","A7","B8" and
"87'' of the DERM harness connector is above specified
value for 500 milliseconds.
~~ 10A 1101 RD
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for a situation which prevents a
proper connection of the
dual pole arming sensor to
the wiring harness.
DIAGNOSTIC AIDS
It is highly unlikely that an intermittent condition has set
this diagnostic
trouble code as this would require a poor
connection at
terminal"1", "2" and "3" or at terminal "4"
, "5" ,
"6" and "7" of Dual Pole Arming Sensor Connector.
IGNmDNt
PASS.38VLR PASS. SOURCE SENSE
PASS SIDE HIGH
PASS SIDE LOW
SERIAL DATA
SRS INDICATOR
Ill

9J-44 Supplemental Restraint System
DTC 15
PASSENGER INITIATOR CIRCUIT RESISTANCE HIGH
CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the
DERM grounds the
"Driver Side Low" terminal "BB" and
turns "ON" the passenger current source at the
"Passenger Side High" terminal "A7". This causes a
known amount of current to
flow through the passenger
initiator circuit. By monitoring the difference between the
voltage at the "Passenger Side High" terminal "A7" and
the "Passenger
Side Low" terminal "B7" the DERM
calculates the combined resistance of the passenger
inflator module, harness wiring CKTs IB21, IB22 and
IB24 and connector terminal contact.
DTC WILL SET WHEN
The combined resistance of the passenger inflator
module,
harness wiring CKT's IB21, IB22, and IB24 and
connector
terminal contact is above a specified value.
This test is run once each ignition cycle during the
"Initiator Assembly Resistance Tesf' when: 1) No "higher
priority faults" are detected during "Turn-ON," 2) No
"higher priority faults" are detected during "Continuous
Monitoring for one second, 3) No "Crank" signal present,
4) "Ignition 1" voltage is above a specified value.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic
trouble code.
DTC WILL CLEAR WHEN
The ignition switch is turned "OFF."
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test determines whether the malfunction is in
the passenger inflator module circuitry or in the
DERM wiring harness circuitry.
3. This test determines whether the malfunction is an
open in CKT's IB"21, IB22, IB24.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection to the passenger
inflator module terminal "2"
or terminal "3" or a poor connection to the DERM at
terminal "A7''. The test for this diagnostic trouble code is
only run while the "AIR BAG" warning lamp is performing
the
bulb check. When a scan tool "Clear Codes"
command is issued and the malfunction is still present,
the
DTC will not reappear until the next ignition cycle.
DRIVER 36VLR PASS. 36VLR PASS. SOURCE SENSE
REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
SERIAL DATA
SRS INDICATOR
Ill

9J-46 Supplemental Restraint System
DTC 16
PASSENGER INITIATOR CIRCUIT RESISTANCE LOW
CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the
DERM grounds the "Driver
Side Low" terminal "B8" and
turns "ON" the passenger current source at the
"Passenger Side High" terminal "A7". This causes a
known amount of current to
flow through the passenger
initiator circuit. By monitoring the difference between the
voltage at the "Passenger Side High" terminal "A7" and
the "Passenger
Side Low" terminal "B7" the DERM
calculates the combined resistance of the passenger
inflator module, harness wiring CKTs IB21, IB22 and
IB24 and connector terminal contact.
DTC WILL SET WHEN
The combined resistance of the passenger inflator
module,
harness wiring CKT's IB21, IB22, and IB24 and
connector
terminal contact is below a specified value.
This test is run once each ignition cycle during the
"Initiator Assembly Resistance Test" when: 1) No "higher
priority
faults" are detected during "Turn-ON," 2) No
"higher priority
faults" are detected during "Continuous
Monitoring" for one second,
3) No "Crank" signal present,
4)
"Ignition 1" voltage is above a specified value.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic
trouble code.
1805
DTC WILL CLEAR WHEN
The ignition switch is turned "OFF."
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. DTC 16 and 22 will set simultaneously when the
"Driver Side High" circuit is shorted to the
"Passenger Side High" circuit due to parallel current
paths.
3. This test determines whether the malfunction is in
the passenger inflator module circuitry or in the
DERM wiring harness circuitry.
4. This test checks for a short from the "Passenger Side
High" circuit to the "Passenger Side Low" circuit.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a short
between CKT's
IB15, IB21, IB24 and CKT's IB10, IB16,
IB19
or CKT's IB17, IB18, IB20, IB22, IB25, IB36. The
test for this diagnostic
trouble code is only run while the
"AIR BAG" warning lamp is performing the bulb check.
When a scan
tool "Clear Codes" command is issued and
the
malfunction is still present, the DTC will not reappear
until the next ignition cycle.
SRS·1 JOINT CONNECTION 12 10 LBOe TO FUSE 1807 ~~~2~--SR~SC~-2+21-0A--~~--~---
IGNITION 1 IGNITION1 1111 1812 1813 DRIVER JeVLR
PASS. 36VLR
PASS. SOURCE
SENSE
REDUNDAT
INDICATOR
GROUND
PASS SIDE HIGH
PASS SIDE LOW
SERIAL DATA
SRS INDICATOR
•