warning ISUZU TROOPER 1995 Workshop Manual

9J-88 Supplemental Restraint System
DTC44
PASSENGER SOURCE FEED LOW
CIRCUIT DESCRIPTION
During normal, non-deployment operation of the SRS
the DERM monitors the voltage supplied through the
dual pole arming sensor to the high side ofthe passenger
deployment
loop at the "Passenger Source Sense"
terminal
"AS". This measured voltage will have a value
approximately equal to "Passenger 3S VLR." When the
voltage measured at "Passenger Side Low" terminal "87"
is in its normal operating range, indicating passenger
deployment
loop integrity has been maintained, while
simultaneously
the voltage measured at "Passenger
Source Sense" is a specified amount below "Passenger
3S VLR" for 500 milliseconds DTC 44 is set.
DTC WILL SET WHEN
The voltage measured at "Passenger Side Low" terminal
"87"
is within a specified percentage of "Passenger 3S
VLR" while simultaneously the voltage measured at
"Passenger Source Sense" terminal "AS" is within a
specified amount
below "Passenger 3S VLR" for 500
milliseconds.
This test is run every 1 00 milliseconds
during the "Continuous Monitoring" tests.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic
trouble code.
TO IGNITION SWITCH
FUSEj SRS C·24
10A , ... D
FUSE SRS C·23 10A 1001
DTC WILL CLEAR WHEN
The voltage measured at "Passenger Side Low" terminal
"87"
is within a specified percentage of "Passenger 3S
VLR" while simultaneously the voltage measured at
"Passenger Source Sense" terminal "AS" is within a
specified amount of "Passenger 3S VLR" for 500
milliseconds.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for an open in "Passenger Source
Sense" circuit.
3. This test checks for a short from the "Passenger
Source Sense" circuit to ground.
4. This test determines whether the malfunction is due
to increased resistance across the
"Passenger
Source Sense" resistor in the dual pole arming
sensor.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection to the DERM at terminal "AS", a poor
connection to the dual pole arming sensor at terminal "1",
an open or short to ground in CKT 1814 or a partial open
inside the
dual pole arming sensor.
SRS-1 JOINT CONNECTION ~ IGNITION1
DRIVER 36VLR PASS. l&VLR PASS. SOURCE SENSE
PASS SIDE HIGH PASS SIDE LOW
1---""--:t--':1--7-7---7---""103"-4 --BLKIBLU 1--""--7-------:7-7--7--'TO ~fc~E-LT_,.,_BLU
~~~~~7----~11~~---W~fflE .J~L -----llli-BRN CONNECTOR 1811 11!120
..

9J-90 Supplemental Restraint System
DTC51
FRONTAL
CRASH DETECTED
CIRCUIT DESCRIPTION
Closure of the dual pole arming sensor is detected when
the voltage measured at "Driver
Side High" terminal "89"
or at "Passenger Side High" terminal "A7" is within a
specified
amount of its respective deployment loop
supply voltage.
Closure of either discriminating sensor is
detected when the voltage measured at "Driver
Side
High" terminal "88" or at "Passenger Side High" terminal
"87" is within a specified amount of ground potential.
When both conditions are met simultaneously
on either
driver side
or passenger side for not less than 250
milliseconds "Crash Data" is recorded and DTC 51 is set.
DTC WILL SET WHEN
Closure of the dual pole arming sensor and at least one
discriminating sensors is detected for not less than
250
microseconds on either the driver side or passenger
side. Conditions are monitored whenever the DERM is
functioning
normally.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp, records
"Crash
Data," and sets a diagnostic trouble code.
TO IGNITION SWITCH
FUSE! SRS C-24 10A 1101 R D
DTC WILL CLEAR WHEN
A scan tool "Clear Codes" command is received by the
DERM.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
3. If inflator module(s) has not deployed, DTC 51 may
have set falsely.
4. If DTC 51 has set with no signs of frontal impact, the
diagnostic trouble code has set falsely.
5. This test checks for a DERM malfunction setting the
diagnostic trouble code.
6. This test checks for a DERM malfunction setting the
diagnostic trouble code.
7. This test determines whether the diagnostic trouble
code was set inadvertently during diagnosis.
8. When a frontal crash has occurred, it is necessary to
perform the indicated procedures to ensure the
SIR
system is fully functional.
IGNITION 1
DRIVER 36VLR PASS.3SVLR PASS. SOURCE SENSE
PASS SIDE HIGH
PASS SIDE LCIW
SERIAL DATA
SAS INDICATOR

9J-92 Supplemental Restraint System
DTC52
CIRCUIT DESCRIPTION
DATA AREA FULL
ACTION TAKEN
When there is a frontal crash of sufficient force to activate
the dual pole arming sensor and at least one of the two
discriminating sensors simultaneously,
DTC 51 is set. At
this time the DERM
will record information regarding SIR
system status and vehicle status in EEPROM. DTC 52
will set when the DERM has stored information regarding
eight frontal crash events.
DTC WILL SET WHEN
The DERM attempts to store frontal crash information
and finds the
EEPROM data area full. This test is run
each time the DERM stores or attempts to store
information regarding a frontal crash event. DERM
turns
"ON" the "AIR BAG" warning lamp and sets
a diagnostic trouble code.
DTC WILL CLEAR WHEN
A scan tool "Clear Codes" command is received by the
DERM.
If, at the next ignition "ON" after receiving a
"Clear Codes" command, the DERM detects the data
area is
full, a history diagnostic trouble code is set. This
allows the "AIR BAG" warming lamp to illuminate should
any additional malfunctions be detected.
SRS·1 FUSE JOINT CONNECTION TO IGNITION SWITCH
FUSE! SRS C·2' 10A 1101 R D
--~SR~S~C~·23~1~0A~-IPNK----~~~~~------------_sn~~»~~~~·~~---l IGJ;~ON __ __.:FU:;:Si-E ____ _.fr;:--___ 1!!!107!!...-___ SWITCH SAS C·22 1 OA
FUSE STARTER 1801
Al~L • 1127 CONNECTOR 1111
1!120
IGNITION1
IGNITION1
DRIVER SOURCE SENSE DRIVER 36VLR PASS. 3SVLR PASS. SOURCE SENSE
REDUNDAT INDICATOR
GROUND
PASS SIDE HIGH
PASS SIDE LOW
SPARQPS DRIVER SEAT BELT
CRANK
SERIAL
DATA
DRIVER SIDE HIGH DRIVER SIDE LOW REDUNDANT INDICATOR
IGNITION 1
SRS INDICATOR
•

9J-94 Supplemental Restraint System
DTC53
DRIVER SIDE LOW HIGH RESISTANCE
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
allowing this resistance to be calculated.
The normal, non-deployment current flow through the
driver
deployment loop is also affected since the DERM
is
supplying ground through a resistor bypassing the
ground
supplied by the resistance of the discriminating
sensor network. When the
voltage difference between
"Driver Side High" terminal "B9" and "Driver Side Low"
terminal "B8" is above a specified value DTC 53 is set.
DTC WILL SET WHEN
The voltage difference between "Driver Side High"
terminal "B9" Driver Side Low" terminal "B8" is above 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-O.N,"
2) No "higher priority faults" are detected dunng
"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 due
to a high resistance or open
in the "Driver Side Low"
circuit between the DERM and the Steering
column
harness connector.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection at DERM
terminal "B8" or an open in CKT
IB20.
The test for this diagnostic trouble code is run only
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.
iYOS BLK/RE
.rBODY t824 VLT IB21J
DRIVER 36VLR PASS. 38VLR PASS. SOURCE SENSE
PASS SIDE HIGH
PASS SIDE LOW
l---....!E:L_-+--4+j-+-___..!!IB3~4--BLK/BLU
~-'!W.-4---4-~----'TO ~iJELT '"*' BLU
SERIAL DATA
DRIVER SIDE HIGH DRIVER SIDE LOW REDUNDANT INDICATOR IGNITION 1
SRS INDICATOR

9J-96 Supplemental Restraint System
DTC54
PASSENGER SIDE LOW HIGH RESISTA E
CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the
DERM grounds the "Passenger Side Low"
terminal "B7''
and turns
"ON" the driver current source at the "Driver
Side High" terminal "B9". this causes a known amount of
current to
flow through the driver initiator circuit allowing
the resistance to be calculated. The normal,
non-deployment current flow through the passenger
deployment loop is also affected since the DERM is
supplying ground through a resistor bypassing the
ground
supplied by the resistance of the discriminating
sensor network. When the
voltage difference between
"Passenger Side
High" terminal "A7" and "Passenger
Side Low''
terminal "B7" is above a specified value DTC
54 is set.
DTC WILL SET WHEN
The voltage difference between "Passenger Side High"
terminal "A7"
and "Passenger Side Low" terminal "B7" is
above 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)"1gnition 1" 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 "Passenger Side
Low" circuit between the DERM and the passenger
inflator module harness connector.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection at DERM
terminal "B7" or an open in CKT.
The test for this diagnostic trouble code is run only 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 1105 1 10 TO FUSE IGNITION SWITCH SRS C-22 10A
PASS SIDE HIGH
PASS SIDE LOW
SERIAL
DATA
SRS INDICA TOR
•

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
•

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

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
•