2004 ISUZU TF SERIES fuse chart

SUPPLEMENTAL RESTRAINT SYSTEM 9A-15

On–Vehicle Service
Service Precaution
WARNING: 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 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 “LOCK” and remove key.
1. Remove SRS fuse “SRS”, from the side of the
driver side of instrument panel fuse block o
r
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 manual.
4. Disconnect yellow 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
CAUTION: Never use the air bag assembly from
another vehicle and difference model year air bag
assembly.
Use only new air bag assembly proper to the
TFR/S which is being repaired.
Turn ignition switch to “LOCK” and remove key.
1. Connect yellow connector passenger air bag
assembly.
2. Install glove box assembly. Refer to “Passenger ai
r
bag assembly replacement” in this manual.
3. Connect yellow connector at the base of steering
column.
4. Install “AIR BAG” fuse “SRS” to the side of the
driver side of instrument panel fuse block o
r
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
manual.

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 sensor pointing
toward the front of the vehicle. It is very 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 replacement.

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:

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.

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.

9A1-14 RESTRAINT CONTROL SYSTEM

Chart C “AIR BAG” Warning Lamp Does Not Come “ON” Steady


RTW49JLF000101

Circuit Description
When the ignition switch is first turned “ON”, “Ignition 1”
voltage is applied from the “METER” fuse to the “AIR
BAG” warning lamp which is connected to “SRS
Warning Lamp”, terminal “39”. The “SRS” fuse appl
y
system voltage to the “Ignition 1” inputs, terminals “35”.
The SRS control unit responds by flashing the “AIR
BAG” warning lamp seven times. If “Ignition 1” is more
than 16 volts, the “AIR BAG” warning lamp will be still
“OFF” solid with no DTCs set.

Chart Test Description
Number(s) below refer to step number(s) on the
diagnostic chart:
1.
This test decides whether power is available to SRS
control unit warning lamp power feed circuit.
2.
This test determines whether the voltage is present
in the warning lamp circuit.
3.
This test determines if the malfunction is in the
instrument cluster.
4.
This test checks for open in the warning lamp
circuitry.
5.
This test isolates the SRS warning lamp circuit and
checks for a short in the SRS warning lamp circuit to
B+.
8.
This test checks for a short from the SRS control
unit warning lamp power feed circuit to ground.
9.
This test determines whether the short to ground is
due to a short in the wiring.

RESTRAINT CONTROL 9A1-15

Chart C “AIR BAG” Warning Lamp Does Not Come “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. Remove and inspect “METER” fuse to the “AIR BAG”
warning lamp.
Is fuse good? Go to Step 2 Go to Step 7
2

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.

3. Disconnect SRS control unit.

4. Ignition switch “ON.”
5. Measure voltage on SRS control unit harness connector from
terminal “39” to terminal “40” (ground).
Is system voltage present on terminal “39”? Go to Step 4 Go to Step 3
3

1. Ignition switch “OFF.”

2. Remove instrument meter cluster.
3. Check for proper connection to instrument cluster at SRS
warning lamp circuit terminal.

4. If ok, then remove and inspect “AIR BAG” bulb.
Is bulb good? Go to Step 5 Replace bulb.
Go to Step 6
4

1. Ignition switch “OFF.”

2. Disconnect instrument meter cluster harness connector.
3. Ignition switch “ON.”

4. Measure voltage on SRS control unit harness connector from
terminal “39” to terminal “40” (ground).
Is voltage 1 volt or less? Go to Chart A Replace SRS
harness.
Go to Step 6
5

1. Install bulb.

2. Measure resistance from instrument meter cluster harness
connector SRS warning lamp circuit terminal to SRS control
unit harness connector terminal “7”.
Is resistance 5.0 ohms or less? Service instrument
meter cluster.
Install instrument
meter cluster.
Go to Step 6 Replace SRS
harness.
Go to Step 6
6 Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished? Repeat the “SRS
Diagnostic System
Check” Go to Step 6
7 Perform chart C.
Was this step finished? Go to Step 8 Go to Step 1
8

1. Replace “METER” fuse.

2. Ignition switch “ON” wait 10 Seconds then ignition switch “Off.
“
3. Remove and inspect “METER” fuse.
Is fuse good? Install “METER”
fuse.
Go to Step 10 Go to Step 9

9A1-16 RESTRAINT CONTROL SYSTEM

Step Action Yes No
9

1. Disconnect SRS coil and passenger air bag assemblies.
Yellow connectors located at base of steering column and
behind the glove box assembly.

2. Disconnect SRS control unit.
3. Replace “METER” fuse.

4. Ignition switch “ON” wait 10 seconds.

5. Ignition switch “OFF”.
6. Remove and inspection “METER” fuse.
Is fuse good? Install “METER”
fuse.
Go to Chart A Replace SRS
harness.
Replace “METER”
fuse.
Go to Step 10
10 Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished? Repeat the “SRS
Diagnostic System
Check” Go to Step 10

BRAKE CONTROL SYSTEM 5A-21

Computer System Service Precautions
The Anti-lock Brake System and Electronic Brake-force
Distribution interfaces directly with the Electronic
Hydraulic Control Unit (EHCU) which is a control
computer that is similar in some regards to the Engine
Control Module. These modules are designed to
withstand normal current draws associated with vehicle
operation. However, care must be taken to avoid
overloading any of the EHCU circuits. In testing for
opens or shorts, do not ground or apply voltage to any
of the circuits unless instructed to do so by the
appropriate diagnostic procedure. These circuits should
only be tested with a high impedance multimeter
5-8840-0366-0 or special tools as described in this
section. Power should never be removed or applied to
any control module with the ignition in the “ON”
position.
Before removing or connecting battery cables, fuses or
connectors, always turn the ignition switch to the “OFF”
position.

General Service Precautions
The following are general precautions which should be
observed when servicing and diagnosing the Anti-lock
Brake System and/or other vehicle systems. Failure to
observe these precautions may result in Anti-lock Brake
System and Electronic Brake-force Distribution
damage.
 If welding work is to be performed on the vehicle
using an electric arc welder, the EHCU and valve
block connectors should be disconnected before
the welding operation begins.
 The EHCU and valve block connectors should
never be connected or disconnected with the
ignition “ON”.
Note:
 If only rear wheels are rotated using jacks or drum
tester, the system will diagnose a speed sensor
malfunction and the “ABS and Brake” warning lamp
will illuminate. But actually no trouble exists. When
the DTC is not detected and the ABS and BRAKE
warning lamp is on, “How to erase code” is
performed and a ABS and BRAKE warning lamp
are off.
If the battery has been discharged
The engine may stall if the battery has been completely
discharged and the engine is started via jumper cables.
This is because the Anti-lock Brake System (ABS) and
Electronic Brake-force Distribution (EBD) System
requires a large quantity of electricity. In this case, wait
until the battery is recharged, or set the ABS and EBD
to a non-operative state by removing the fuse for the
ABS. After the battery has been recharged, stop the
engine and install the ABS fuse. Start the engine again,
and confirm that the ABS warning Lamp does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to
identify an intermittent failure. In such a case
duplicating the system malfunction during a test drive or
a good description of vehicle behavior from the
customer may be helpful in locating a “most likely”
failed component or circuit. The symptom diagnosis
chart may also be useful in isolating the failure. Most
intermittent problems are caused by faulty electrical
connections or wiring. When an intermittent failure is
encountered, check suspect circuits for:
 Suspected harness damage.
 Poor mating of connector halves or terminals not
fully seated in the connector body (backed out).
 Improperly formed or damaged terminals.

Test Driving ABS Complaint Vehicles
In case that there has been an abnormality in the
lighting pattern of “ABS” warning lamp, the fault can be
located in accordance with the “DIAGNOSIS BY “ABS”
WARNING LAMP ILLUMINATION PATTERN”. In case
of such trouble as can be detected by the driver as a
vehicle symptom, however, it is necessary to give a test
drive following the test procedure mentioned below,
thereby reproducing the symptom for trouble diagnosis
on a symptom basis:
1.
Start the engine and make sure that the “ABS” W/L
goes OFF. If the W/L remains ON, it means that
the Diagnostic Trouble Code (DTC) is stored.
Therefore, read the code and locate the fault.
Note: The DTC cannot be cleared if the vehicle speed
does not exceed about 6km/h (4mph) at DTC, even
though the repair operation is completed.
2. Start the vehicle and accelerate to about 30 km/h
(19 mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to about 40
km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and stop
the vehicle.
6. Be cautious of abnormality during the test. If the
W/L is actuated while driving, read the DTC and
locate the fault.
7. If the abnormality is not reproduced by the test,
make best efforts to reproduce the situation
reported by the customer.
8. If the abnormality has been detected, repair in
accordance with the “SYMPTOM DIAGNOSIS” .
Note:

Be sure to give a test drive on a wide, even road
with a small traffic.
 If an abnormality is detected, be sure to suspend
the test and start trouble diagnosis at once.