ISUZU TROOPER 1995 Workshop Manual

Supplemental Restraint System 9J-97
DTC54
PASSENGER SIDE LOW HIGH RESISTANCE
STEP
ACTION YES NO
1 WAS THE "SRS
DIAGNOSTIC
SYSTEM CHECK" GOTOSTEP2. GO TO THE "SRS PERFORMED? DIAGNOSTIC
SYSTEM CHECK."
2
WHEN MEASUREMENTS ARE REQUESTED IN THIS CHART GO TO CHART A. GOTOSTEP3.
USE J 39200 DVM WITH CORRECT TERMINAL ADAPTER FROM J 35616-A. IGNITION SWITCH "OFF."
DISCONNECT DRIVER
AND PASSENGER INFLATOR
MODULES, YELLOW 2-WAY OR 4-WAY CONNECTORS LOCATED AT THE TOP OF THE STEERING COLUMN AND BEHIND THE 1/P COMPARTMENT DOOR ASSEMBLY. DISCONNECT DERM. CHECK FOR
PROPER CONNECTION TO DERM AT TERMINAL "B7".
IF
OK THEN MEASURE RESISTANCE FROM DERM HARNESS
CONNECTOR TERMINAL "B7" TO PASSENGER INFLATOR
MODULE HARNESS CONNECTOR TERMINAL "3".
IS
RESISTANCE S.OilOR LESS?
3 REPLACE
SRS HARNESSRECONNECT ALL SRS GO TO THE "SRS DIAGNOSTIC SYSTEM
COMPONENTS,
ENSURE ALL COMPONENTS ARE CHECK". PROPERLY MOUNTED. CLEAR SRS DIAGNOSTIC TROUBLE CODES. REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK."

9J-98 Supplemental Restraint System
DTC55
DERM INCOMPATIBILITY
CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the
DERM grounds the "Passenger
Side Low" terminal "B7"
and measures the voltage at "Driver Source Sense"
terminal "AS" , "Passenger Source Sense" terminal "A6"
and "Driver Side Low" terminai"B8". The DERM monitors
"Driver
Source Sense" to ensure that "Driver 36 VLR" is
fully charged and supplying voltage to the high side of the
driver deployment loop. When this condition is met, the
measurement at "Passenger
Source Sense" indicates
no voltage is being
supplied to the high side of the
passenger deployment loop and grounding "Passenger
Side Low'' does no ground "Driver Side Low," DTC 55 is
set.
DTC WILL SET WHEN
The conditions described above indicate a driver only
DERM has been installed in the vehicle. This test is run
once each ignition cycle during the
"Initiator Assembly
Resistance
Test" when: 1)No "higher priority faults" are
detected during
"Tum-oN," 2)No "higher priority faults"
are detected during "Continuous Monitoring
" for one
second, 3}No
"Crank" signal present, 4)"1gnition 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 due
to a high resistance
or open in the "DIAGNOSTIC
CODES REQUEST"
circuit between the DERM and
the ground.
3. This test determines whether the malfunction

is due
to a high resistance or open in the
"DIAGNOSTIC
CODES REQUEST"
circuit between the DERM and
the ground.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection at DERM terminal
"AS" or an open in CKT
IY06.
The test for this diagnostic trouble code is run only
while the "AIR BAG" warning lamp is performing
command is issued and the malfunction is still present,
the
DTC will not reappear until the next ignition cycle. ~
PASS.:MVUI PASS. SOURCe SENSE
PASS SlOE HIGH PASS SlOE LOW
SERIAL DATA
•

Supplemental Restraint System 9J-99
DTC55
DERM INCOMPATIBILITY
STEP ACTION YES NO
1
WAS THE "SRS DIAGNOSTIC SYSTEM CHECK'' GOTOSTEP2. GO TO THE "SRS
PERFORMED? DIAGNOSTIC
SYSTEM CHECK."
2 WHEN MEASUREMENTS ARE REQUESTED IN THIS CHART
REPLACE DERM. GOTO STEP3
USE
J-39200 DVM WITH CORRECT TERMINAL ADAPTER REPEAT THE "SRS
FROM J-35616-A. DIAGNOSTIC
IGNITION SWITCH
"OFF"DISCONNECT DRIVER AND SYSTEM CHECK."
PASSENGER INFLATOR MODULES.
YELLOW 2-WAY OR 4-WAY CONNECTORS LOCATED AT THE TOP OF THE STEERING COLUMN AND BEHIND THE liP COMPARTMENT DOOR ASSEMBLY. DISCONNECT DERMCHECK FOR PROPER CONNECTION
TO DERM AT TERMINAL "AS". IF OK THEN MEASURE RESISTANCE ON DERM HARNESS CONNECTOR FROM TERMINAL "AS" TO TERMINAL "A1".
IS RESISTANCE 5.00 OR LESS?
3 MEASURE RESISTANCE ON DERM HARNESS CONNECTOR REPLACE DERM. GOTO STEP4.
FROM TERMINAL "AS" TO TERMINAL "A 12".
REPEAT THE "SRS
IS RESISTANCE 5.00 OR LESS? DIAGNOSTIC
SYSTEM CHECK."
4 ·REPLACE SRS HARNESS RECONNECT ALL SRS GO TO THE "SRS DIAGNOSTIC SYSTEM
COMPONENTS
ENSURE ALL COMPONENTS ARE CHECK". PROPERLY MOUNTED.
CLEAR SRS DIAGNOSTIC TROUBLE CODES. REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK."

9J-1 00 Supplemental Restraint System
DTC61
SRS
INDICATOR CIRCUIT FAIL E
CIRCUIT DESCRIPTION
When the ignition switch is first turned "ON" battery
voltage is applied to the
"AIR BAG" warning lamp and to
the
"Ignition 1" input terminals "A9" and "A10". The
DERM responds by flashing the
"AIR BAG" warning lamp
seven
times alternating between the primary and
redundant lamp drivers. The DERM monitors the primary
lamp driver output by comparing the output state at
"SRS
Indicator" terminal "B1" to the microprocessor
commanded state. When "Ignition 1" is above a specified
value and the output state does not match the
commanded state of the primary lamp driver for 400
milliseconds DTC61 is set.
DTC WILL SET WHEN
"Ignition 1" voltage is above a specified value and the
output state at the
"SRS Indicator" terminal "B1" does not
match the commanded state of the primary lamp driver
for 400 milliseconds. This test is run every 100
milliseconds during "Continuous Monitoring" tests.
ACTION TAKEN
DERM attempts to turn "ON" the "AIR BAG" warning
lamp using
the redundant lamp driver 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. When the DERM is configured for a serial data
controlled warning lamp (smart cluster) DTC61 will
set. Clearing
SRS diagnostic trouble codes will reset
the DERM allowing the DERM to control the
"AIR
BAG"
warning lamp.
DIAGNOSTIC AIDS
Refer to CHARTS B and C to diagnose warning lamp
circuit malfunctions.
Ill

Supplemental Restraint System 9J-101
DTC61
CATOR CIRCUIT FAILURE
STEP ACTION YES NO
1 WAS THE "SRS
DIAGNOSTIC SYSTEM CHECK" GOTO STEP2. GO
TO THE "SRS
PERFORMED? DIAGNOSTIC
SYSTEM CHECK."
2 MALFUNCTIONS WITHIN THE "AIR BAG" WARNING LAMP IGNITION SWITCH REPEAT THE "SRS
CIRCUITRY WILL SET THIS DIAGNOSTIC TROUBLE CODE. "OFF." DIAGNOSTIC
THESE MALFUNCTIONS
ARE ADDRESSED IN THE "SRS GO TO CHART A. SYSTEM CHECK."
DIAGNOSTIC SYSTEM CHECK" VIA
CHART BAND CHART C. FAILURE TO PROPERLY PERFORM THE "SRS DIAGNOSTIC
SYSTEM CHECK'' MAY RESULT IN MISDIAGNOSIS OF A MALFUNCTIONING DERM.
IGNITION SWITCH "ON". CLEAR SRS DIAGNOSTIC TROUBLE CODES.
IS DTC 61 SET?

9J-102 Supplemental Restraint System
DTC62
REDUNDANT SRS INDICATOR CIRCUIT FAIL RE
CIRCUIT DESCRIPTION
When the ignition switch is first turned "ON" battery
voltage is applied to the
"AIR BAG" warning lamp and to
the
"Ignition 1" input terminals "A9" and "A10". The
DERM responds by flashing the
"AIR BAG" warning lamp
seven
times alternating between the primary and
redundant lamp drivers. The DERM monitors the
redundant lamp driver output by comparing the output
state at "SRS Indicator" terminal "B1" to the
microprocessor commanded state. When
"lgnition1" is
above a specified value and the output state does not
match the commanded state of the redundant lamp
driver for
400 milliseconds DTC 62 is set.
DTC WILL SET WHEN
"Ignition 1" voltage is above a specified value and the
output state at the
"SRS Indicator'' terminal "B 1" does not
match the commanded state of the redundant lamp
driver for
400 milliseconds. This test is run every 100
milliseconds during "Continuous Monitoring" tests.
FUSE
ACTION TAKEN
DERM attempts to turn "ON" the "AIR BAG" warning
lamp using the primary lamp driver 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 checks for an open in the "Redundant
Indicator Ground"
circuit.
3. This test determines whether the malfunction is due
to
an open in the "Redundant Indicator Ignition 1"
circuit.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection to the DERM at terminal
"A2" or "B2", an open
in
CKT IY05 or an open in CKT IB03.
SRS-1 JOINT CONNECTION ___ sR~SrC~·23~1_M ___ ,PNK:----~"~~------------~"~~~~18~~~--TO IGNITION SWITCH IGNITION 1
FUSE!
SRS C-24 lOA 1800 RED
WKT/RED IGJ~oN --- REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
DRIVER SEAT BELT
CRANK
SERIAL DATA
DRIVER SIDE HIGH DRIVER SIDE LOW REDUNDANT INDICATOR
IGNITION 1
SRS INDICATOR

Supplemental Restraint System 9J-103
DTC62
REDUNDANT SRS INDICATOR CIRCUIT FAILURE
STEP
ACTION YES NO
1 WAS THE "SRS
DIAGNOSTIC
SYSTEM CHECK'' GOTOSTEP2. GO TO THE "SRS PERFORMED? DIAGNOSTIC
SYSTEM CHECK."
2 IS DTC 61 ALSO SET? GOTO DTC61. GOTOSTEP3.
3
WHEN MEASUREMENTS ARE REQUESTED IN THIS CHART GOTOSTEP4. GOTOSTEP5.
USE J-39200 DVM WITH CORRECT TERMINAL ADAPTER FROM J-35616-A. IGNITION SWITCH "OFF."
DISCONNECT DRIVER
AND PASSENGER INFLATOR
MODULES, YELLOW 2-WAY OR 4-WAY CONNECTORS
LOCATED AT THE TOP OF THE STEERING COLUMN AND BEHIND THE 1/P COMPARTMENT DOOR ASSEMBLY.
DISCONNECT DERM. CHECK FOR PROPER CONNECTION
TO DERM AT TERMINAL "A2" AND AT TERMINAL "B2".
IF OK THEN MEASURE RESISTANCE ON DERM HARNESS
CONNECTOR FROM TERMINAL
"A2"
(GROUND) TO
TERMINAL "A 12" (GROUND). IS RESISTANCE 5.00 OR LESS?
4 IGNITION SWITCH "ON." GOTOSTEP6. GNITION SWITCH MEASURE
VOLTAGE ON DERM HARNESS CONNECTOR "OFF."
FROM TERMINAL "B2" TO TERMINAL "A12" (GROUND). GO TO CHART A.
IS VOLTAGE 1 VOLT OR LESS?
5 REPLACE SRS HARNESS. GOTOSTEP7.
6 IGNITION SWITCH "OFF."REPLACE SRS HARNESS. GOTOSTEP7.
7 RECONNECT ALL SRS COMPONENTS, ENSURE ALL GO TO THE "SRS DIAGNOSTIC SYSTEM
COMPONENTS ARE PROPERLY MOUNTED. CHECK".
CLEAR SRS DIAGNOSTIC TROUBLE CODES. REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK."

9J-1 04 Supplemental Restraint System
DESCRIPTION
DTC 71 AND/OR 75
INTERNAL DERM FAULT CIRCUIT
ACTION TAKEN
DTC 71 and/or DTC 75 is an indication of an internal
DERM malfunction and
will set if any of the following
conditions are detected:1 )DERM energy reserve voltage
discharge time failure for three consecutive ignition
cycles("Turn-ON" test), 2)DERM is unable to read from
or write to EEPROM(tested during
"EEPROM read/write
cycle"), 3)Either
"36 VLR" power supply voltage is above
a specified value for
500 milliseconds ("Continuous
Monitoring" test), 4)The DERM calculated number for
the vehicle
in which it is installed does not match the
value stored in EEPROM. DERM
turns
"ON" the "AIR BAG" warning lamp and sets
a diagnostic trouble code.
DTC WILL SET WHEN
Any of the indicated malfunctions are detected by the
DERM. Each of the failure conditions is tested at a
different time: 1 )At "Turn-ON," 2)Asynchronously,
3)During "Continuous Monitoring," 4)At
"Turn-ON."
DTC WILL CLEAR WHEN
The indicated malfunctions are not detected by the
DERM.
FUSE JOINT C~~N~CTION TO IGNITION
ru • .'jWITCH
SRS C-24 1~ , ... R D
--~SR~S~C~-~.1~~~-IPNK----~~·~~------------~~~w--~1-~---
>N-~~4---.::r---::r----___!!'B!!!!oa'-------WHT/REO
AL~L____mz._BRN CONNECTOR IB1t
1120
IGNITION 1 IGNITION 1 DRIVER SOURCE SENSE DRIVER 36VLR PASS.35VLR PASS. SOURCE SENSE
REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
SERIAL DATA
DRIVER SIDE HIGH DRIVER SIDE LOW REDUNDANT INDICATOR IGNITION1
SRS INDICATOR
•

STEP
1 WAS THE "SRS PERFORMED?
Supplemental Restraint System 9J-1 05
\: DTC 71 AND/OR 75
INTERNAL DERM FAULT
ACTION
YES
DIAGNOSTIC SYSTEM CHECK"
REPLACE DERM.
REPEAT THE "SRS
DIAGNOSTIC SYSTEM CHECK." NO
GO TO
THE "SRS
DIAGNOSTIC SYSTEM CHECK."

9J-106 Supplemental Restraint System
DTC81
DRIVER IGNITION DIODE OPEN
CIRCUIT DESCRIPTION
During the "Turn-ON" tests, performed at the beginning
of each ignition
cycle, the DERM delays the charging of
the "Driver
3S VLR" and "Passenger 3S VLR" power
supplies. While the delay is active the DERM measures
the
voltage at the "Driver 3S VLR" terminal "A3", "Driver
Source
Sense" terminal "AS", and "Passenger Source
Sense" terminal "AS". When the voltage measured at the
two
"3S VLR" power supplies indicates they are in a
discharged state, the
voltage measured at "Passenger
Source
Sense" is within a specified range of "Ignition 1"
voltage
measured at "Driver Source Sense" is a specified
amount
below "Ignition 1" voltage DTC 81 is set.
DTC WILL SET WHEN
With both "3S VLR" power supplies in a discharged state,
the DERM detects
"Ignition 1" voltage at "Passenger
Source
Sense" terminal "AS" while simultaneously the
DERM detects
"Ignition 1" voltage at "Driver Source
Sense" terminal "AS". This test is run once each ignition
cycle during the "Turn-ON" tests while the "3S VLR
Delay"
is active.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic
trouble code.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for a short from the "Driver Source
Sense" circuit to the "Passenger 3S VLR" circuit.
3. This test checks for a short from the "Driver Source
Sense"circuit to the "Driver
3S VLR" circuit.
4. This test determines whether the malfunction is due
to open within the
dual pole arming sensor.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a short
between
CKT 1811 CKTIB12, a short between CKT 1811
and CKT 1813 or an open inside the dual pole arming
sensor. The test for this diagnostic
trouble code is only
run while the check. When a scan tool "Clear Codes"
command is issued and the malfunction is still present,
the
DTC will not reappear until the ignition switch is
turned
"OFF" for at least two minutes with the entire SRS
connected and then the ignition switch is turned "ON."
SRS-1 FUSE JOINT CONNECTION TOS~~~:?N -_;:,;SR-" !
IGNmON ~-=-------"T"---""'1107<----SWrTCH SRS C-22 10A 1111
1112 DRIVER 36VLR PASS.36VLR PASS. SOURCE SENSE
REOUNOAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
SERIAL DATA
SRS INDICATOR
•