run flat ISUZU TROOPER 1995 Owner's Manual

9J-62 Supplemental Restraint System
DTC 24 (PAGE 2 OF 3)
INITIATOR CIRCUIT VOLTAGE LOW
CIRCUIT DESCRIPTION
During normal, non-deployment operation of the SRS,
a small amount of current flows through both the driver
and
passenger deployment loops. The diagnostic
resistors within the dual pole arming sensor and the
discriminating sensors
along with the resistance of the
inflator modules cause voltage drops within the
deployment loops. The DERM monitors the voltage at
"Driver
Side Low" terminal "88" and "Passenger Side
Low" terminal "87"
to detect shorts or opens within the
driver deployment
loop. When the measured voltage at
terminal "88" or "87" is below a specified percentage of
its respective Driver 36 VLR power
supply voltage for
500 milliseconds DTC 24 is set.
DTC WILL SET WHEN
The voltage measured at "Driver Side Low'' terminal "88"
is below a specified percentage of "Driver 36 VLR" or
when the
voltage measured at "Passenger Side Low"
terminal "87" is below a specified percentage of
"Passenger 36 VLR" for 500 milliseconds. This test is run
during the "Continuous Monitoring" test.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic
trouble code.
""
DTC WILL CLEAR WHEN
The voltage measured at "Driver Side Low" terminal "88"
is within a specified percentage of "Driver 36 VLR" and
the
voltage measured at "Passenger Side Low" terminal
"87"
is within a specified percentage of "Passenger 36
VLR" for 500 milliseconds.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
10. This test checks for a short from the low side of the
driver deployment
loop to ground.
11. This test checks for a partial short across the
diagnostic resistor in the forward discriminating
sensor.
12.
This test checks for a partial short across the
diagnostic resistor in the passenger compartment
discriminating sensor.
13. This test checks for a short from the discriminating
sensor interconnect circuit to ground.
14. This test checks for a short from the
low side of the
driver deployment
loop to ground.
DIAGNOSTIC AIDS
Refer to DTC 24(Page 1 of 3).
SRS-1 JOINT CONNECTION 1 10 180& IGNITION 1 IGNITION 1 DRIVER SOURCE SENSE DRIVER 36VLR PASS. 38VLR PASS. SOURCE SENSE
AEOUNDAT INotCATOR GROUND
PASS SlOE HIGH PASS SIDE LOW
SPARE/LPS
SERIAL DATA
SRS INDICATOR

9J-64 Supplemental Restraint System

DTC 24 {PAGE 3 OF 3) \
INITIATOR CIRCUIT VOLTAGE LOW
CIRCUIT DESCRIPTION
During normal, non-deployment operation of the SRS,
a small amount of current flows through both the driver
and passenger deployment loops. The diagnostic
resistors within the dual pole arming sensor and the
discriminating sensors along with the resistance of the
inflator modules cause voltage drops within the
deployment loops. The DERM monitors the voltage at
"Driver Side Low" terminal "88" and "Passenger Side
Low"
terminal "87" to detect shorts or opens within the
driver deployment loop. When the measured voltage at
terminal
"88" or "87" is below a specified percentage of
its respective Driver 36 VLR for
500 milliseconds DTC 24
is set.
DTC WILL SET WHEN
The voltage measured at "Driver Side Low'' terminal "88"
is below a specified percentage of "Driver 36 VLR" or
when the voltage measured at "Passenger
Side Low"
terminal "87" is below a specified percentage of
"Passenger 36 VLR" for 500 milliseconds. This test is run
during the "Continuous Monitoring" test.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
a diagnostic trouble code.
DTC WILL CLEAR WHEN
The voltage measured at "Driver Side Low" terminal "88"
is within a specified percentage of "Driver 36 VLR" and
the voltage measured at "Passenger
Side Low" terminal
"87" is within a specified percentage of "Passenger 36
VLR" for 500 milliseconds.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
22. This test determines whether the malfunction is a
short from the high side of the passenger
deployment loop to ground. ·
23This test determines whether the malfunction is a
short from the high side of the Driver deployment
loop to ground.
24. This test checks for an open in the driver deployment
loop diagnostic resistor
of the dual pole arming
sensor.
25. This
test checks for an open in the passenger
deployment for an open in the passenger
deployment loop diagnostic resistor of the dual pole
arming sensor.
26. This test checks for high resistance in the "Driver 36
VLR" circuit.
27.
This test checks for high resistance in the
"Passenger 36 VLR" circuit.
28.
This test checks for high side of the driver
deployment loop.
29. This test checks for
an open in the high side of the
passenger deployment loop.
DIAGNOSTIC AIDS
Refer to DTC 24(Page 1 of 3).

9J-66 Supplemental Restr.aint System
DTC 25 (PAGE 1 OF 2)
INITIATOR CIRCUIT SHORT TO IGNITION
CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the
DERM grounds the
"Driver Side Low" terminal "BB" and
measures the voltage at "Driver Side Low" and
"Passenger Side Low." The DERM then grounds
"Passenger Side Low" terminal "B7" and again measures
the
voltage at "Driver Side Low" and "Passenger Side
Low."
For a properly operating circuit the voltage
measures the voltage measurements during each of
these tests
will be below a specified value. When the
voltages measured at both "Driver Side Low" and
"Passenger
Side Low'' are above a specified value during
both tests
DTC 25 is set.
DTC WILL SET WHEN
The voltages measured at both "Driver Side Low" and
"Passenger
Side Low" are above a specified value while
the DERM attempts to ground each of these terminals.
This test is run during the
"Initiator Assembly Resistance
Test" and the "1 0 Minute Loop Test" when: 1) "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 voltages measured at either "Driver Side Low" or
"Passenger
Side Low" is below a specified value while
the DERM ground either of these terminals.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test determines whether the malfunction is
occurring
in the steering column circuitry.
3. This test determines whether the malfunction is
occurring
in the passenger inflator module circuitry.
4. This test for a short from the SRS COIL to +B.
DIAGNOSTIC AIDS
Refer to DTC 25(Page 2 of 2).
IGNmON 1 IGNITION 1 DRIVER SOURCE SENSE
~ -
DRIVER 38VLR PASS. 38VLR PASS. SOURCE SENSE 1DA 1&14 111011 D
REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
SPARE/l.PS DRIVER SEAT BelT
SERIAL DATA
SRS INDICATOR

9J-78 Supplemental Restraint System
DTC35 ~
DISCRIMINATING SENSOR OPEN OR MISSING
CIRCUIT DESCRIPTION
During normal, non-deployment operation of SRS a
small amount of current flows through both the driver and
passenger deployment loops.The diagnostic resistors
within the dual pole arming sensor and the discriminating
sensors along with the resistance of the inflator modules
cause voltage drops within the deployment loops.The
DERM monitors the voltage at "Driver Side
Low" terminal
"B8" and "Passenger Side Low" terminal "B7' to detect
shorts or opens within the deployment loops.When the
measured voltage at either terminal is within a specified
percentage of its respective
"36 VLR" power supply
voltage for
500 milliseconds DTC 35 is set.
DTC WILL SET WHEN
The voltage measured at "Driver Side Low" terminal "B8"
and "Passenger Side Low" terminal "B7" is within a
specified percentage
of its respective "36 VLR"a power
supply voltage 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.
...
DTC WILL CLEAR WHEN
The voltages measured at "Driver Side Low" terminal
"B8" and "Passenger Side Low" terminal "B7" are both
above or
below the respective "36 VLR" power supply
voltage which sets
DTC 35.
DTC CHART TEST DESCRIPTION
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for an open inside the forward LH
discriminating sensor.
3. This test checks for an open inside the
Eng-ROOM(forward LH discriminating sensor
Jumper) HARNESS.
4. This test checks for an open inside the forward RH
discriminating sensor.
5. This test checks for an open inside the Engine room
(forward
RH Discriminating Sensor Jumper)
DIAGNOSTIC AIDS
An intermittent condition is likely to be an improper
connection at any of the discriminating sensor terminals,
an open in either ground feed to the discriminating
sensors,
an open discriminating sensor interconnect
ciircuit, increased resistance
of any discriminating
sensor or decreased resistance of the dual pole arming
sensor.
SRS-1 JOINT CONNECTION ,, .
DRIVER 38VLA PASS. 38VLA PASS. SOURCE SENSE
REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
f---""------o~---4--'T--:f----7-------'..,_-BLKJBLU f---.!W...----o~---4--'T--:)--ITO ~~tc~~BLU
N-:1~i7-7?--.J!2!L--wHTI!'ED Al~L __..Jlli__ BAN CONNECTOR 111t
SERIAL DATA
DRIVER SIDE HIGH DRIVER SIDE lOW REDUNDANT INDICATOR IGNffiON 1
..

9J·82 Supplemental Restraint System
DTC37
HYBRID INFLATOR LOW PRESSURE
CIRCUIT DESCRIPTION
During normal "Ignition 1" voltage is applied from the
"C-23" fuse trough passenger low peraaaure warning
sensor to DERM st
"LPS" terminal "83". When the
pressure in the gas cylinder within the passenger inflator
module is operating normally the measured voltage will
be the same voltage as "Ignition 1" voltage. If the
passenger
low pressure warning sensor circuit opens or
short to ground the voltage measured st
"LPS" will
decrease to near ground voltage. When the voltage
measured
at"LPS" is outside the specified renge DTC 37
is set.
DTC WILL SET WHEN
The voltage measured at "LPS" terminal "83" is outside
the specified renge. This test is run every 100
milliseconds during "Continuous Montoring" tests.
ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets
diagnostic trouble code.
DTC WILL CLEAR WHEN
The voltage measured at "LPS" terminal "83" is within a
specified rande which doesn't the diagnostic trouble
code, svery
100 milliseconds.
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 high resistance
in the "Passenger Low Pressure
Warning
Sensor."
3. This test checks for an open onside the "LPS" circuit.
4. This test checks for a short from the "LPS" cirsuit to
ground.
DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor
connection Passenger
Inflator Module terminal "1" or "4"
poor connection at DERM terminal "83", an open in CKT
1834 or CKT 1834 or an open inside the Passenger
Inflator Module.
SRS-1 JOINT CONNECTION 10 , ... IGNITION!
IGNITION 1 ORIVER SOURCE SENSE DRIVER 38VLR PASS.3eVLR PASS. SOURCE SENSE
REDUNDAT INDICATOR GROUND
PASS SIDE HIGH
PASS SIDE LOW
SPARE/I.PS DRIVER SEAT BELT
SERIAL DATA
DRIVER SIDE HIGH DRIVER SIDE LOW REDUNDANT INDICATOR IGNITION!
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
•

Supplemental Restraint System 9J-117
SERVICE PRECAUTIONS
CAUTION: WHEN PERFORMING SERVICE ON OR
AROUND SRS COMPONENTS OR SRS WIRING,
FOLLOW
THE PROCEDURES LISTED BELOW TO
TEMPORARILY
DISABLE THE SRS. FAILURE TO
FOLLOW PROCEDURES COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY OR OTHERWISE UNNEEDED SRS
REPAIRS.
The DERM in Driver-Passenger SRS can maintain
sufficient voltage to cause a deployment for up to 2
minutes after the ignition switch is turned to
"OFF," the
battery is disconnected, or the fuse powering the DERM
is removed.
Many of the service procedures require removal of the
"AIR BAG" fuse, and disconnection of the inflator
modules from the deployment loop to avoid an accidental
deployment.
If the inflator module is disconnected from
the deployment loop as noted in the "Disabling the
SRS"
procedure that follows, service can begin immediately
without waiting for the 2 minute time period to expire.
DISABLING THE SRS
REMOVAL
• Turn the steering wheel so that the vehicle's wheels
are pointing straight ahead.
• Turn the ignition switch to "OFF"
1. Remove SRS fuse C-21, C-22, C-23 and C-24 from
left dash side lower fuse block.
2. Disconnect yellow
3-way connector at the base of
the steering column.
3. Remove
liP compartment door assembly, Refer to
"Passenger inflator module replacemenf' in section
9J-135.
4. Disconnect yellow 4-way connector behind the liP
compartment door assembly.
NOTE
• With the" AIR BAG" fuse removed and ignition switch
"ON," the "AiR BAG" warning lamp will be "ON." This
is normal operation and does not indicate
an SRS
malfunction.
ENABLING THE SRS
INSTALLATION
Turn ignition switch to "LOCK" and remove key.
1. Connect yellow 4-way connector of passenger
inflator module.
2. Install liP compartment door assembly, Refer to
"Passenger inflator module replacement" in section
9J-3.
3. Connect yellow 3-way connector at the base of the
steering column.
4. Install" AIR BAG" fuse C-21, C-22, C-23 and C-24 to
left dash side lower fuse block.
Tum ignition switch to
"RUN" and verify that the "AIR
BAG"
warning lamp flashes seven times and then turns
"OFF" If it does not operate as described, perform the
"SRS Diagnostic System Check" in section 9J-32.
HANDLING/INSTALLATION/DIAGNOSIS
1. Inflator modules should not be subjected to
temperatures above 65°C(150°F).
2. Discriminating s~nsors, inflator modules, arming
sensors, or DERMs should not be used if they have
been dropped from a height of 1
00 centimeters (3.28
feet) or more.
3. When a discriminating sensor or arming sensor is
replaced, it MUST be oriented with the arrow
on the
sensor pointing toward the front of the vehicle.
It is
very important for the discriminating sensors and
arming sensor to be located flat on the mounting
surface, parallel to the vehicle datum line.
It is
important that the sensor mounting surface is free of
any dirt or other foreign material.
4. Do not apply power to the SRS unless all
components are connected or a diagnostic chart
requests it, as this
will set a diagnostic trouble code.
5. The
"SRS Diagnostic System Check'' must be the
starting point of any SRS diagnostics. The
"SRS
Diagnostic System Check" will verify proper "AIR
BAG" warning lamp operation and 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 replacements.
INSPECTIONS REQUIRED AFTER ACCI­
DENT
CAUTION: CERTAIN SRS COMPONENTS MUST BE
REPLACED AFTER A FRONTAL
CRASH INVOLVING
AIR
BAG DEPLOYMENT.
In all types of accident regardless of "Air Bag"
deployment, visually inspect all the following
components and their points and replace as required:
- Passenger
Inflator Module
- Steering wheel
- SRS coil assembly
- Steering column
- Knee bolster and
Instrument panel mounting