1995 ISUZU TROOPER Workshop Manual

Supplemental Restraint System 9J-33
SRS DIAGNOSTIC SYSTEM CHECK
STEP
ACTION YES NO
1 NOTE "AIR BAG" WARNING LAMP AS IGNITION SWITCH IS GOTOSTEP2 GOTOSTEP3 TURNED "ON."
DOES WARNING
LAMP FLASH 7 TIMES?
2 NOTE "AIR BAG" WARNING LAMP AS ENGINE IS STARTED. GOTOSTEP4 GO TO CHART D. DOES WARNING LAMP COME "ON" STEADY DURING
CRANKING?
3 DOES WARNING LAMP FLASH 4 TIMES? GOTO DTC62. GO TO STEPS.
4 NOTE "AIR BAG" WARNING LAMP AFTER STARTING. GOTOSTEP6 GOTOSTEP7 DOES WARNING LAMP FLASH 6 TIMES THEN GO "OFF"?
5 DOES WARNING LAMP COME "ON" STEADY? GO TO CHART B. GO TO CHART C.
6 IGNITION SWITCH "OFF." IF
NO SRS DIAGNOSTIC TROUBLE CODES
CONNECT SCAN TOOL TO
DATA LINK CONNECTOR, ARE DISPLAYED. GOTO STEP 8. FOLLOW DIRECTIONS AS GIVEN IN THE SCAN TOOL
INSTRUCTION MANUAL.
IGNITION SWITCH "ON."
IF HISTORY DIAGNOSTIC TROUBLE CODES
REQUEST SRS DIAGNOSTIC TROUBLE CODE DISPLAY, ARE DISPLAYED. GOTO STEP 9. RECORD ALL HISTORY DIAGNOSTIC TROUBLE CODES,
SPECIFYING AS SUCH, ON REPAIR ORDER.
7 IGNITION SWITCH "OFF." IF DIAGNOSTIC TROUBLE CODES ARE
CONNECT SCAN TOOL TO DATA LINK CONNECTOR, DISPLAYED. GOTO STEP 10. FOLLOW DIRECTIONS AS GIVEN IN THE SCAN TOOL
INSTRUCTION MANUAL. IGNITION SWITCH "ON."
REQUEST SRS DIAGNOSTIC
TROUBLE CODE DISPLAY, RECORD ALL DIAGNOSTIC TROUBLE CODES SPECIFYING
AS CURRENT OR HISTORY ON REPAIR ORDER.
8
SRS IS FUNCTIONAL AND FREE OF MALFUNCTIONS.
NO FURTHER DIAGNOSIS IS REQUIRED.
9 IGNITION SWITCH "OFP'. WHEN DTC 83 IS SET, GO TO DTC 83 CHART. WHEN DTC 84 IS SET, GO TO DTC 84 CHART. FOR ALL OTHER HISTORY DIAGNOSTIC TROUBLE CODES, REFER TO "DIAGNOSTIC AIDS" FOR THAT
SPECIFIC DIAGNOSTIC TROUBLE CODE. A HISTORY DTC INDICATES THE MALFUNCTION HAS BEEN REPAIRED OR IS INTERMITTENT.
10 DIAGNOSTIC
TROUBLE CODES ARE DISPLAYED.
IGNITION SWITCH "OFF."
WHEN DTC 51 IS SET, GO TO DTC 51 CHART. DIAGNOSE REMAINING CURRENT DIAGNOSTIC TROUBLE CODES FROM LOWEST TO HIGHEST. WHEN ONLY HISTORY DIAGNOSTIC TROUBLE CODES EXIST, REFER TO "DIAGNOSTIC AIDS" FOR THAT SPECIFIC DIAGNOSTIC TROUBLE CODE. A HISTORY DTC INDICATES THE MALFUNCTION
HAS BEEN
REPAIRED OR IS INTERMITTENT.

9J-34 Supplemental Restraint System
TABLE A
DERM INTEGRITY CHECK
CIRCUIT DESCRIPTION
When the DERM recognizes "Ignition 1" voltage, applied
to terminals "A9" and "A10", is in the normal operating
voltage range, the "AIR BAG" warning lamp is flashed 7
timestoverifyoperation. At this time the DERM performs
"Turn-ON" tests followed by "Continuous Monitoring"
tests. When no malfunctions are detected the DERM
proceeds to the
"Initiator Assembly Resistance Test."
When a malfunction
is detected the DERM sets a current
diagnostic
trouble code and illuminates the "AIR BAG"
warning lamp. The DERM will clear current diagnostic
trouble codes and move them to a history file when the
malfunction is no
longer detected and/or the ignition
switch is
cycled, except for DTC 51. DTC 51 can only be
cleared using a scan tool "Clear Codes" command.
TO IGNITION SWITCH
FUSEl SRS C-24 lOA .... R D
CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic table.
1. This test confirms a current malfunction. If no current
malfunction is occurring(history DTC set) the
"Diagnostic Aids" for the appropriate diagnostic
trouble code should be referenced. The DERM
should not be replaced for a history diagnostic
trouble code.
2. This test checks for a malfunction introduced into the
SRS during the diagnostic process. It is extremely
unlikely
that a malfunctioning DERM would cause a
new malfunction to occur during the diagnostic
process.
3. When all circuitry outside the DERM has been found
to operate
properly, as indicated by the appropriate
diagnostic chart, then and
only then should the
DERM be
replaced.
IGNITION!
IGNITION
1
DRIVER 36VLR PASS.36VLR PASS. SOURCE SENSE
PASS SlOE HIGH
PASS SIDE LOW
SPARE/LPS
--------------------~&--~/
..

STEP
2
3
Supplemental Restraint System 9J-35

TABLE A
DERM INTEGRITY CHECK
ACTION
THIS
CHART ASSUMES THAT THE "SRS DIAGNOSTIC
SYSTEM CHECK" AND EITHER A SYMPTOM CHART OR A
DIAGNOSTIC TROUBLE CODE CHART DIAGNOSIS HAVE BEEN PERFORMED. WHEN ALL CIRCUITRY OUTSIDE THE
DERM HAS BEEN FOUND TO OPERATE PROPERLY, AS
INDICATED BY THE APPROPRIATE DIAGNOSTIC CHART, AND THE SYMPTOM OR DTC REMAINS CURRENT, THE FOLLOWING.
DIAGNOSTIC PROCEDURES MUST BE PERFORMED TO VERIFY THE NEED FOR DERM REPLACEMENT. IGNITION SWITCH "OFF."
RECONNECT
ALL SRS COMPONENTS, ENSURE ALL
COMPONENTS ARE PROPERLY MOUNTED.
ENSURE THE IGNITION SWITCH HAS BEEN "OFP' FOR AT LEAST TWO MINUTES.
NOTE"AIR BAG" WARNING LAMP AS IGNITION SWITCH IS TURNED "ON."
DOES WARNING LAMP FLASH 7 TIMES THEN GO "OFF"?
USING
A SCAN TOOL REQUEST DIAGNOSTIC TROUBLE CODE DISPLAY. IS THE SAME SYMPTOM OR DTC OCCURRING AS WAS WHEN THE SRS DIAGNOSTIC SYSTEM CHECK "WAS FIRST
PERFORMED"
CLEAR SRS DIAGNOSTIC TROUBLE CODES.
"IGNITION SWITCH "OFP' FOR AT LEAST TWO MINUTES.
NOTE "AIR BAG" WARNING LAMP AS IGNITION SWITCH IS TURNED "ON."
DOES WARNING LAMP FLASH 7 TIMES THEN GO "OFF"? YES
THE SYMPTOM OR DTC IS NO LONGER
OCCURRING. CLEAR SRS
DIAGNOSTIC
TROUBLE CODES. REPEAT THE "SRS
DIAGNOSTIC SYSTEM CHECK."
GOTOSTEP3.
SRS IS
FUNCTIONAL AND
FREE OF
MALFUNCTIONS.
NO FURTHER DIAGNOSIS IS REQUIRED. NO
GOTO STEP2.
IGNITION
SWITCH
"OFF." GO
TO THE APPROPRIATE CHART FOR THE INDICATED MALFUNCTION.
IGNITION SWITCH
"OFF."
GOTO STEP4
4 REPLACE DERM. GO TO THE "SRS DIAGNOSTIC SYSTEM
RECONNECT ALL SRS COMPONENTS, ENSURE ALL CHECK"
COMPONENTS ARE PROPERLY MOUNTED.
REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK.

9J-36 Supplemental Restraint System
TABLE B
"AIR BAG" WARNING LAMP COMES "ON" STEADY
CIRCUIT DESCRIPTION
When the ignition switch is first turned "ON," "Ignition 1"
voltage is applied from the "C-21" fuse to "Redundant
Indicator Ignition 1 ,"terminal "B2", and to the "AIR BAG"
warning lamp which is connected to "SRS Indicator,"
terminal "B1". The "C-22·C-23" fuses apply system
voltage to the
"Ignition 1" inputs, terminals "A9" and
"A10". The DERM responds by flashing the "AIR BAG"
warning lamp 7 times. If "Starter" is outside of the normal
operating voltage range, the
"AIR BAG" warning lamp
will
come "ON" solid with no DTCs set. When the engine
is being cranked,
"Ignition 1" voltage is applied from the
"C-1" fuse to the DERM at the "Crank" input. The DERM
responds by grounding the
"SRS" Indicator" output until
"Starter" voltage is removed from the "Crank'' input. This
results in the
"AIR BAG" warning lamp being "ON" during
cranking.After cranking, the DERM
will flash the "AIR
BAG" warning lamp 6 times.
CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic table.
1. An open "C-22-C-23" fuses would cause the "AIR
BAG" warning lamp to come "ON" steady.
2. A disconnected DERM harness connector will cause
the warning
lamp to come "ON" steady via the
shorting clip from terminal "A1" to terminal "81".
3. This test checks whether the short to ground caused
the
"C-1" fuse to open.
4. This test checks for an open in the ground circuitry
to the DERM.
5. This test determines whether the short to ground is
due to a malfunctioning dual pole arming sensor or
a short
in the wiring.
6. This test checks for an open in the "Ignition 1"
circuitry to the DERM.
7. This test checks for a short from the "SRS Indicator''
circuit to ground.
8. This test checks for a short from the "Crank" input
circuit to 8+.
SRS-1 JOINT CONNECTION TO IGNITION FUSE SRS C·23 10A 1!015 '12 10 IGNITION I IGNITION 1 SWITCH
FUSE~ SRS C-24 10A .... R D
PASS.3eVLR PASS. SOURCE SENSE
PASS SlOE HIGH
PASS SlOE LOW
SERIAL DATA
SRS INDICATOR
..

Supplemental Restraint S~m 9J-37
TABLE B
"AIR BAG" WARNING LAMP COMES "ON" STEADY
STEP ACTION YES NO
1 WHEN MEASUREMENTS ARE REQUESTED IN THIS CHART USEJ-39200 DVM GotoStep2. GotoStep3. WITH CORRECTTERMINALADAPTER FROMJ-35616-A. WHEN A CHECK FOR PROPER CONNECTION IS REQUESTED. IGNITION SWITCH "OFF."
REMOVE AND INSPECT "C-22·C-23" FUSE.
IS FUSE GOOD?
2 INSPECT DERM HARNESS CONNECTOR CONNECTION TO DERM. GotoStep4. PROPERLY CONNECT
IS IT SECURELY CONNECTED TO THE DERM? DERM HARNESS
CONNECTOR TO DERM. INSTALL C-22·C-23 FUSE. GotoStep11.
3 REPLACEC-22·C-23 FUSE.JGNITION SWITCH "ON," WAIT 10SECONDS, THEN INSTALL C-22·C-23 Go to StepS.
IGNITION SWITCH "OFF."
FUSE.
REMOVE
AND INSPECT C-22·C-23 FUSE. IS FUSE GOOD? GotoStep11.
4 DISCONNECT DERM.CHECK FOR PROPER CONNECTION TO DERM AT Go to StepS REPLACE /SRS
TERMINALS "A1", "A9", "A10" AND "A12". HARNESS. IF OK, THEN MEASURE RESISTANCE FROM DERM HARNESS CONNECTOR RECONNECT DERM. TERMINAL "A1" TO "A2". INSTALL C-22·C-23 IS
RESISTANCE 5.00 OR LESS?
FUSE. Go to Step11.
5 DISCONNECT DUAL POLE ARMING SENSOR. REPLACE DUAL POLE REPLACE SRS REPLACE C-22·C-23 FUSE.
ARMING SENSOR. HARNESS.
IGNITION SWITCH "ON," WAIT 10 SECONDS, THEN IGNITION SWITCH "OFF .. INSTALL C-22·C-23 RECONNECT DUAL POLE
REMOVE AND INSPECT C-22·C-23 FUSE. FUSE. ARMING
IS FUSE GOOD? GotoStep11. SENSOR. REPLACE C-22·C-23 FUSE. Go to Step11.
6 INSTALL C-22·C-23 FUSE. IGNITION SWITCH GotoStep7. IGNITION SWITCH "ON."
"OFF."
MEASURE VOLTAGE FROM DERM HARNESS REPLACE SRS
CONNECTOR TERMINAL "A1"(GROUND) TO TERMINAL "A9". HARNESS.
IS VOLTAGE 1 VOLT OR LESS? RECONNECT DERM. INSTALL C-22·C-23 FUSE. GotoStep11.
7 INSTALL C-22·C-23 FUSE.DISCONNECT DRIVER AND PASSENGER GotoStep11. Go to StepS.
INFLATOR MODULES, YELLOW 2-WAY OR 4-WAY CONNECTORS LOCATED NEAR THE BASE OF STEERING COLUMN AND BEHIND THE liP COMPARTMENT DOOR ASSEMBLY.
CONNECT DERM HARNESS CONNECTOR TO J41433 SRS
DRIVER/PASSENGER LOAD TOOL.
IGNITION SWITCH "ON."
DOES "AIR
BAG" WARNING LAMP COME "ON"?
8 IGNITION SWITCH "OFF."
IGNITION SWITCH "OFF .. Go to Step10.
DISCONNECT SRS DRIVER/PASSENGER LOAD TOOL. Go to CHART A. IGNITION SWITCH "ON."
MEASURE VOLTAGE ON DERM HARNESS CONNECTOR FROM TERMINAL
"B10" TO TERMINAL "A1"(GROUND). IS VOLTAGE 1 VOLT OR LESS?
9 IGNITION SWITCH "OFF." GotoStep11. DISCONNECT SRS DRIVER/PASSENGER LOAD TOOL. REPLACE SRS HARNESS.
10 IGNITION SWITCH "OFF." Go to Step11. REPLACE SRS HARNESS.
11 RECONNECT ALL SRS COMPONENTS,
GO TO THE "SRS DIAGNOSTIC SYSTEM CHECK" ENSURE ALL COMPONENTS ARE PROPERLY MOUNTED.
REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK."