1995 ISUZU TROOPER Workshop Manual

, Supplem~l Restraint System
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.
SRS DRIVER/PASSENGER LOAD TOOL
The SRS Driver/Passenger Load Tool J-41433 is used
only when called for in this section. It is used as a
diagnostic aid and safety device to prevent inadvertent
inflator
module deployment.
The
load tool has four yellow connectors attached to its
case.
The three
small connectors are electrically functional
and serve as resistive
load substitutions. The large
dummy connector does not serve as a load substitution
but
merely takes the physical place of the DERM
connector when needed.
No more than two connectors are used at any time.
One
of the small connectors is used to substitute for the load
of the driver inflator module when it is connected at the
top of the
column to the SRS coil assembly. Another
small connector is used to substitute for the load of the
driver inflator
module and the SRS coil assembly when
it is connected at the base of the
column to the SRS
wiring harness. The third small connector is used to
substitute for the
load of the passenger inflator module
when connected to the passenger inflator module
harness connector.
By substituting the resistance of the
load tool when called
for, a determination can be made as to whether an
inflator circuit component is causing system malfunction
and which component is causing the malfunction. The
load tool should be used only when specifically called for
in the diagnostic procedures.
9J-25

9J-26 Supplemental Restraint System
J 39200 DVM
The J 39200 DVM is the preferred DVM for use in SRS ~
diagnosis and repair. However, J 34029-A may be used
if
J 39200 is not available. No other DVMs are approved
for
SRS diagnosis and repair.
SCAN TOOL
The Tech 1 is used to read and clear SRS Diagnostic
Trouble Codes (DTCs). Refer to the Tech 1 Operator's
Manual for specific information on how to use the Tech
1.
Scan tools from other manufacturers may be used. Refer
to the Operator's Manual for the tool for specific
instructions.
J 35616-A CONNECTOR TEST ADAPTER
KIT
The J 35616-A Connector Test Adapter Kit must be used
whenever a diagnostic procedure requests checking or
probing a
terminal. Using the appropriate adapter will
ensure that no damage to the terminal will occur from the
DVM prove, such as spreading or bending. The adapter
will also give an idea of whether contact tension is
sufficient,
helping to find an open or intermittent open due
to poor
terminal contact.
J-41434 SRS DEPLOYMENT TOOL
J 41497 SRS DEPLOYMENT FIXTURE

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-28 Supplemental Restraint System

DTC 34 DUAL POLE ARMING SENSOR IGNITION FEED OPEN •••••••.••• \> ...... .
DTC 35 DISCRIMINATING SENSOR OPEN OR MISSING •••••••••••••••••.•\
•••••
DTC 36 PASSENGER LOOP ENERGY RESERVE FEED OPEN ••••••••••••••..•••
76
78
~
80
DTC 37 HYBRID INFLATOR LOW PRESSURE . . • • • • • • • • . • • • • • • • • • • . • • • . .

.
• • • • . . 82
DTC 42
LOOP ENERGY RESERVE VOLTAGE LOW • • • • • • • • • • • • • . • • • • . .

.
• . • . . • • • 84
DTC 43
DRIVER SOURCE FEED LOW • • . • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • . • • • • • • • 86
DTC 44
PASSENGER SOURCE FEED LOW • . • • . • • • • • • • • • • • • • • • . . • . • . • . . • • . . . • • 88
DTC
51 FRONTAL CRASH DETECTED • • • • • . • • • • • • • • . • • • • • • • • • • • • • • • . . • • • . • • • • 90
DTC 52 DATA AREA FULL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
DTC 53 DRIVER SIDE LOW HIGH RESISTANCE • • • • • • • • • • • • • • • • • • • . • • • • • . • • • • . • 94
DTC 54
PASSENGER SIDE LOW HIGH RESISTANCE • • • • . • • • • • • . • • • • • . . • . • . . • . • 96
DTC 55 DERM
INCOMPATIBILITY • • • • . • • • . • . • • • • • • • • • • • • • • • • • • • • • . . • . . • . • • • • . • 98
DTC
61 SRS INDICATOR CIRCUIT FAILURE • • • • • • • • • • • • • • • • • • • • • • • • . • • • . • • • • • • 100
DTC 62 REDUNDANT SRS INDICATOR CIRCUIT FAILURE • • • • • • • . .

. .
• . .
. . . .
• • . • 102
DTC 71 AND/OR 75 INTERNAL DERM FAULTCIRCUIT • • • • • • • • • • • • • • • . • • • • • • • . . • 104
DTC 81 DRIVER IGNITION DIODE OPEN • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 106
DTC 82 PASSENGER IGNITION DIODE OPEN • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • . • 108
HISTORY
DTC 83 DRIVER RESERVE DIODE SHORTED • • • • • • • • • • • • • . • • . • • • . • • • 110
HISTORY
DTC 84 PASSENGER RESERVE DIODE SHORTED •••••••••.•••.•..•••

MEMO
\ Supplemental Restraint Systern 9J-29 ( \,

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.