ignition ISUZU TF SERIES 2004 User Guide

SUPPLEMENTAL RESTRAINT SYSTEM 9A-27

Service Precautions for SRS
Component Service
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 fo
r
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.
WARNING: WHEN PERFORMING SERVICE ON O
R
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 SRS control unit in Driver–Passenger SRS can
maintain sufficient voltage to cause a deployment for
up to 15 seconds after the ignition switch is turned
“OFF,” the battery is disconnected, or the fuse
powering the SRS control unit is removed.
Many of the service procedures require removal of the
“SRS” fuse, and disconnection of the air bag assembly
from the deployment loop to avoid an accidental
deployment. If the air bag assembly is disconnected
from the deployment loop as noted in the “Disabling
the SRS” procedure that follows, service can begin
immediately without waiting for the 15 second time
period to expire.

Disabling The SRS
Removal
Turn the ignition switch to “OFF” and turn the steering
wheel so that the vehicle's wheels are pointing straight
ahead.
1. Remove SRS fuse “SRS” from left dash side lowe
r
fuse block or disconnect battery.
2. Disconnect yellow connector at the base o
f
steering column.
3. Remove glove box assembly; Refer to “Passenge
r
air bag assembly replacement” in this section.
4. Disconnect passenger air bag assembly yello
w
connector behind the glove box assembly.
CAUTION: With the “SRS” 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 connector passenger air bag
assembly.
2. Install glove box assembly. Refer to “Passenge
r
Air Bag Assembly Replacement” in this section.
3. Connect yellow connector at the base of the
steering column.
4. Install “AIR BAG” fuse “SRS” to left dash side
lower fuse block or connect battery.
Turn ignition switch to “ON” 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 this
section.

Handling / Installation / Diagnosis
1. Air bag assembly should not be subjected to
temperatures above 65

C (150

F).
2. Air bag assembly, and SRS control unit should not
be used if they have been dropped from a height
of 100 centimeters (3.28 feet) or more.
3. When a SRS control unit is replaced, it must be
oriented with the arrow on the SRS control unit
pointing toward the front of the vehicle. It is ver
y
important for the SRS control unit to be located flat
on the mounting surface, parallel to the vehicle
datum line. It is important that the SRS control unit
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 ma
y
result in extended diagnostic time, incorrect
diagnosis, and incorrect parts replacements.

Inspections Required After An Accident
CAUTION: Certain SRS components must be
replaced after a frontal crash involving air bag
deployment.
In all types of accidents regardless of “Air Bag”
deployment, visually inspect all of the following
components and replace as required:

9A-46 SUPPLEMENTAL RESTRAINT SYSTEM

Pretensioner Seat Belt (If so quipped)
Service Precaution
WARNING: WHEN PERFORMING SERVICE ON OR
AROUND THE PRETENSIONER SEAT BELT O
R
THE PRETENSIONER SEAT BELT WIRING,
FOLLOW THE PROCEDURES LISTED BELOW TO
TEMPORARILY DISABLE THE PRETENSIONE
R
SEAT BELT.
FAILURE TO FOLLOW PROCEDURES COULD
RESULT IN POSSIBLE THE PRETENSIONER SEAT
BELT DEPLOYMENT, PERSONAL INJURY O
R
OTHERWISE UNNEEDED THE PRETENSIONE
R
SEAT BELT REPAIR.
AS A PRECAUTION, WEAR GLOVES AND SAFETY
GLASSES WHEN PERFORMING THE
PRETENSIONER SEAT BELT. WHEN DEPLOY A
LIVE PRETENSIONER SEAT BELT AT OUTSIDE
THE VEHICLE, DEPLOYMENT HARNESS SHALL
REMAIN SHORTED AND NOT BE CONNECTED TO
A POWER SOURCE UNTIL THE PRETENSIONE
R
SEAT BELT IS TO BE DEPLOYED. THE
PRETENSIONER SEAT BELT WILL IMMEDIATELY
DEPLOY WHEN A POWER SOURCE IS
CONNECTED TO IT. CONNECTING THE
DEPLOYMENT HARNESS SHOULED ALWAYS BE
THE FINAL STEP IN THE PRETENSIONER SEAT
BELT DEPLOYMENT PROCEDURE. FAILURE TO
FOLLOW PROCEDURES IN THE ORDER LISTED
COULD RESULT IN PERSONAL INJURY.
Parts Location


RTW49JSH000301
Legend
(1) Seat
(2) Bolt
(3) Pretensioner Harness
(4) Pretensioner

Removal
1. Turn ignition switch to “LOCK”, remove key.
2. Remove the foot rest located behind the seat.
3. Remove the cover on seat slide.
4. Disconnect the pretensioner connector at the
base of the seat.
5. Remove four fixing bolts the seat slide and
remove seat.
6. Remove the seat cover.
7. Remove the pretensioner seat belt assembly.
Installation
1. Install the pretensioner seat belt assembly.
2. Install the seat cover.
3. Install the seat on seat slide and four fixing bolts.
4. Connect the yellow pretensioner connector at the
base of the seat.
5. Install the cover on seat slide.
6. Install the foot rest located behind the seat.

RESTRAINT CONTROL 9A1-3

Diagnostic Information
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.


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, 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.
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 prope
r
“AIR BAG” warning lamp 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.
Preforming 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 SRS control unit maintains a history record of all
diagnostic codes that have been detected since the
SRS codes were last cleared during service.
1. Active Codes - Faults that are presently detected this
ignition cycle. Active 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. (Electronically Erasable
Programmable Read only Memory)

How To Read Trouble Codes
All codes (Active and history) can be read (or cleared)
by using a scan tool or equivalent.
If a PDT is not available, have the vehicle serviced by
HOLDEN 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 an 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 DLC 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 SRS control unitSRS control unit
“Serial Data” output (terminal 21) to the DLC 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

9A1-4 RESTRAINT CONTROL SYSTEM

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 can be used to read active
codes and to determine if history codes are present but
cannot be used to clear codes or read history codes.
Flash code diagnostics is enabled by grounding by
terminal 4 shorting to terminal 13 of the DLC connector
with the ignition switch “ON”. Grounding terminal 4 of
the DLC connector pulls the “Diagnostics Request”
input (Terminal 1) of the SRS control unit low and
signals the SRS control unit to enter the flash code
diagnostic display mode.


060R300052

9A1-8 RESTRAINT CONTROL SYSTEM

Circuit Description
When the ignition switch is first turned “ON”, “Ignition 1”
voltage is applied from the “SRS” fuse to the SRS
control unit at the “Ignition 1” input terminals “35”. The
SRS control unit responds by flashing the “AIR BAG”
warning lamp seven times, while performing tests on
the SRS.

Notes On System Check Chart
1.
The “AIR BAG” warning lamp should flash seven
times after ignition is first turned “ON”.
2.
After the “AIR BAG” warning lamp flashes seven
times, it should turn “OFF”
3.
This test checks for the proper operation of the
“Serial Data” line. This test will also determine
whether history diagnostic trouble codes are stored
and, if so, identify them.
4.
Improper operation of the “AIR BAG” warning lamp
is indicated. This test differentiates a warning lamp
stays “ON” condition from a warning lamp does not
come “ON” condition.
5.
This test checks for proper operation of the “Serial
Data” line. This test will also identify the stored
diagnostic trouble codes and whether they are
current or history.
Diagnostic Aids
The order in which diagnostic trouble codes are
diagnosed is very important. Failure to diagnose the
diagnostic trouble codes in the order specified may
result in extended diagnostic time, incorrect diagnosis
and incorrect parts replacement.


SRS Diagnostic System Check
Step Action Yes No
1 Note the “Air Bag” warning lamp as ignition switch is turned “ON.”
Does the “AIR BAG” warning lamp flash seven 7 times? Go to Step 2 Go to Step 3
2 Note the “AIR BAG” warning lamp after it flashed 7 times.
Does the “AIR BAG” warning lamp go “OFF”? Go to Step 4 Go to Step 5
3 Note the “AIR BAG” warning lamp as ignition switch is turned
“ON”.
Does the “AIR BAG” warning lamp come “ON” steady? Go to Chart B. Go to Chart C.
4
1.
Note the “AIR BAG” warning lamp as that ignition switch is
turned “ON.”

Ignition switch “OFF.”

2.
Connect a scan tool to data link connector.

3.
Follow direction given in the scan tool instruction manual.

Ignition switch “ON.”

4.
Request the SRS diagnostic trouble code display, recode all
history diagnostic trouble code(s). specify as such, on repair
order
Is (are) diagnostic trouble code(s) displayed? Ignition switch
“OFF.”
When DTC B1000 is
set, go to DTC
B1000 Chart.
For all other history
codes refer to
“Diagnostic Aids”
For that specific
DTC.
A history DTC
indicates the
malfunction has
been repaired or is
intermittent. SRS is functional
and free of
malfuncitons, no
further diagnosis is
required.
If scan tool indicated
“NO DATA
RECEIVED,” refer to
chassis electrical
section 8.

RESTRAINT CONTROL 9A1-9

Step Action Yes No
5
1. Ignition switch “OFF.”
2. Connect a scan tool to data link connector.

3. Follow directions as given in the scan tool instruction
manual.

4. Ignition switch “ON.”
5. Request the SRS diagnostic trouble code display, Recode
all diagnostic trouble code(s), specifying as current or history
on repair order.
Is (are) diagnostic trouble code (s) displayed? Ignition switch
“OFF”.
When DTC B0053 is
set, go to DTC
B0053 chart.
When DTC B0051 is
set, go to DTC
B0051 chart.
When DTC B0018
is set, go to DTC
B0018 chart.
When DTC B0024
is set, go to DTC
B0024 chart.
Diagnose remaining
current DTCs from
lowest to highest.
When only history
DTCs exist, refer to
“Diagnostics Aids”
for that specific
DTC.
A history DTC
indicates the
malfunction has
been repaired or is
intermittent. If scan tool indicates
“No Data Received,”
refer to chassis
electrical section 8.

9A1-10 RESTRAINT CONTROL SYSTEM

Chart A SRS control unit Integrity Check


RTW49JLF000101

Circuit Description
When the SRS control unit recognizes “Ignition 1”
voltage, applied to terminals “35”, is greater than 9
volts, the “AIR BAG” warning lamp is flashed 7 times to
verify operation. At this time the SRS control unit
performs “Turn–ON” tests followed by “Continuous
Monitoring” tests. When a malfunction is detected, the
SRS control unit sets a current diagnostic trouble code
and illuminates the “AIR BAG” warning lamp. The SRS
control unit 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 DTCs B0051 and B0053.

Chart Test Description
Number(s) below refer to step number(s) on the
diagnostic chart:
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 SRS control
unit 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 SRS control unit would
cause a new malfunction to occur during the
diagnostic process.

RESTRAINT CONTROL 9A1-11

3.
When all circuitry outside the SRS control unit has
been found to operate properly, as indicated by the
appropriate diagnostic chart, then and only then
should the SRS control unit be replaced.


Chart A SRS control unit Integrity Check
WARNING: DURING SERVICE PROCEDURES. BE VERY CAREFUL WHEN HANDLING A SRS CONTROL
UNIT. NEVER STRIKE OR JAR THE SRS CONTROL UNIT. NEVER POWER UP THE SRS WHEN THE SRS
CONTROL UNIT IS NOT RIGIDLY ATTACHED TO THE VEHICLE. ALL SRS CONTROL UNIT AND MOUNTING
BRACKET FASTENERS MUST BE CAREFULLY TORQUED AND THE ARROW MUST BE POINTING TOWARD
THE FRONT OF THE VEHICLE TO ENSURE PROPER OPERATION OF THE SRS. THE SRS CONTROL UNIT
COULD BE ACTIVATED WHEN POWERED WHILE NOT RIGIDLY ATTACHED TO THE VEHICLE WHICH COULD
CAUSE DEPLOYMENT AND RESULT IN PERSONAL INJURY

Step Action Yes No
1

1. 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 SRS control unit has been found to
operate properly, as indicated by the appropriate diagnostic
chart, and the symptom or DTC remains current, the
following

2. Diagnostic procedures must be performed to verify the need
for SRS control unit replacement.

3. Ignition switch “OFF”.
4. Reconnect all SRS components, ensure all components are
properly mounted.

5. Ensure the ignition switch has been “OFF” for at least 15
seconds.

6. Note “AIR BAG” warning lamp as ignition switch is turned
“ON.”
Does warning lamp flash 7 times then go “OFF”? The symptom or
DTC is no longer
occurring.
Clear SRS
diagnostic trouble
codes.
Repeat “SRS
Diagnostic System
Check” Go to Step 2
2 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? Go to Step 3 Ignition switch
“OFF”.
Go to the
appropriate chart for
the indicated
malfunction.
3
1. Clear “SRS Diagnostic Trouble Codes”.

2. Ignition switch “OFF” for at least two minutes.

3. Note “AIR BAG” warning lamp as ignition switch is turned
“ON.”
Does warning lamp flash 7 times then go “OFF”? SRS is functional
and free of
malfunctions.
No further diagnosis
is required.
Go to Step 4 Ignition switch
“OFF”.
Replace SRS control
unit.
Go to Step 4
4 Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished? Repeat the “SRS
Diagnostic System
Check” Go to Step 4

9A1-12 RESTRAINT CONTROL SYSTEM

Chart B “AIR BAG” Warning Lamp Comes “ON” Steady


RTW49JLF000101

Circuit Description
When the ignition switch is first turned “ON”, “Ignition 1”
voltage is applied from the “METER” fuse to “AIR
BAG”, warning lamp which is connected to “SRS
Warning Lamp”, terminal “39”. The “SRS” fuses appl
y
system voltage to the “Ignition 1” inputs, terminals “35”.
The SRS control unit responds by flashing the “AIR
BAG” warning lamp 7 times. If “Ignition 1” is less than
9 volts, the “AIR BAG” warning lamp will come “ON”
solid with no DTCs set.
Chart Test Description
Number(s) below refer to step number(s) on the
diagnostic chart:
2.
This test checks for an open in the “Ignition 1” circuit
to the SRS control unit.
3.
This test checks for the voltage of “Ignition 1”.
4.
This test determines whether the malfunction is a
short to ground in SRS waring lamp circuit.

RESTRAINT CONTROL 9A1-13

Chart B “AIR BAG” warning lamp comes “ON” Steady

Step Action Yes No
1

1. When measurements are requested in this chart use 5-8840-
0285-0 DVM with correct terminal adapter from 5-8840-
0385-0.

2. Ignition switch “OFF.”

3. Connect scan tool to data link connector, follow directions as
given in the scan tool instruction MANUAL.

4. Ignition switch “ON.”

5. Request SRS diagnostic trouble code display.
Dose scan tool indicate “No Data Received”? Go to Step 2 Go to Step 3
2

1. Ignition switch “OFF”.

2. Inspect SRS control unit harness connector connection to
SRS control unit.
Is it securely connected to the SRS control unit? Ignition switch
“OFF.”
Replace SRS
control unit.
Go to Step 5 Connect SRS
control unit
securely to de–
activate shorting
clip in SRS control
unit harness
connector.
Go to Step 5
3 Using scan tool, request SRS data list.
Is “ignition” more than 9 volts? Go to Step 4 Ignition switch
“OFF.”
Replace SRS
control unit.
Go to Step 5
4

1. Ignition switch “OFF.”

2. Disconnect SRS coil and passenger air bag assemblies.
yellow connector located at base of steering column and
behind the glove box assembly.
Disconnect SRS control unit.

3. Disconnect the connector of “SRS Warning Lamp” of
instrument cluster.

4. Measure resistance from SRS control unit harness connector
terminal “40” to ground.
Does 5-8840-0285-0 DVM display “OL” (Infinite)? Go to Chart A Replace SRS
harness.
Go to Step 5
5 Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished? Repeat the “SRS
Diagnostic System
Check” Go to Step 5