9A-14 SUPPLEMENTAL RESTRAINT SYSTEM
Component Description
SRS Control Unit
WARNING: DURING SERVICE PROCEDURES, BE
VERY CAREFUL WHEN HANDLING A SRS
CONTROL UNIT. NEVER STRIKE OR JAR THE SRS
CONTORL 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 POINTED 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.
The SRS control unit is designed to perform the
following functions in the SRS:
1. Energy Reserve — The SRS control unit maintains 30–Volt Loop Reserve (30VLR) energy supply to
provide deployment energy when ignition voltage is
lost in a frontal crash.
2. Frontal Crash Detection — The SRS control unit monitors vehicle velocity changes to detect frontal
crashes which are severe enough to warrant
deployment.
3. Air Bag Deployment — W hen a frontal crash o
f
sufficient force is detected, the SRS control unit
will cause enough current to flow through the ai
r
bag assembly to deploy the air bag.
4. Malfunction Detection — The SRS control unit performs diagnostic monitoring of SRS electrical
components and sets a diagnostic trouble code
when a malfunction is detected.
5. Frontal Crash Recording — The SRS control unit records information regarding SRS status during
frontal crash.
6. Malfunction Diagnosis — The SRS control unit displays SRS diagnostic trouble codes and system
status information through the use of a scan tool.
7. Driver Notification — The SRS control unit warns the vehicle driver of SRS malfunctions b
y
controlling the “SRS” warning lamp.
The SRS control unit is connected to the SRS wiring
harness by a 52–pin connector. This harness
connector uses a shorting clip across certain terminals
in the contact area. This shorting clip connects the
“SRS” warning lamp to ground when the SRS control
unit harness connector is disconnected or CP
A
(Connector Position Assurance) is not inserted even i
f
completely connected. This will cause the “SRS”
warning lamp to come “ON” steady whenever the
ignition switch is at the ON or START positions with
the SRS control unit disconnected.
RTW 79ASH000401
Legend
(1) SRS Control Unit
(2) SRS Harness
“SRS” Warning Lamp
Ignition voltage is applied to the “SRS” warning lamp
when the ignition switch is at the ON or START
positions. The SRS control unit controls the lamp b
y
providing ground with a lamp driver. The “SRS”
warning lamp is used in the SRS to do the following:
1. Verify lamp and SRS control unit operation b
y
flashing SEVEN (7) times when the ignition switch
is first turned “ON”.
2. W arn the vehicle driver of SRS electrical system malfunctions which could potentially affect the
operation of the SRS. These malfunctions could
result in nondeployment in case of a frontal crash
or deployment for conditions less severe than
intended.
The “SRS “ warning lamp is the key to drive
r
notification of SRS malfunctions. For proper lamp
operation, refer to the “SRS Diagnostic System Check”
in this section.
BACK TO CHAPTER INDEX TO MODEL INDEXISUZU KB P190 2007
9A-32 SUPPLEMENTAL RESTRAINT SYSTEM
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 a 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 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 the 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 assembl
y
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 the SRS fuse “SRS” from the left dash side lower fuse block or disconnect the battery.
2. Disconnect the yellow connector at the base o
f
steering column.
3. Remove the glove box assembly; Refer to “Passenger air bag assembly replacement” in this
section.
4. Disconnect the passenger air bag assembly yello
w
connector behind the glove box assembly.
CAUTION: With the “SRS” fuse removed and the
ignition switch to “ON,” the “SRS” warning lamp
will be “ON.” This is normal operation and does
not indicate an SRS malfunction.
Enabling The SRS
Installation
Turn the ignition switch to “LOCK” and remove the
key.
1. Connect the yellow connector passenger air bag assembly.
2. Install the glove box assembly. Refer to “Passenger Air Bag Assembly Replacement” in
this section.
3. Connect the yellow connector at the base of the steering column.
4. Install the “AIR BAG” fuse “SRS” to the left dash side lower fuse block or connect the battery.
Turn the ignition switch to “ON” and verify that the
“SRS” warning lamp flashes seven times and then
turns to “LOCK”. 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. W hen 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 “SRS”
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.
BACK TO CHAPTER INDEX TO MODEL INDEXISUZU KB P190 2007
RESTRAINT CONTROL SYSTEM 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 carefull
y
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
“SRS” 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 Has
Been Performed.
Performing the “SRS Diagnostic System Check” after all repairs 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 in 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 the 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 a
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 a ISUZU/GM
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 and turn the ignition switch “ON”.
Then follow the manufacturer's directions fo
r
communication with the SRS. The scan tool reads
serial data from the SRS control unit’s “Serial Data”
output (terminal 21) to the DLC (terminal 2).
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
9A1-8 RESTRAINT CONTROL SYSTEM
Circuit Description
W hen 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 “1”. The
SRS control unit responds by flashing the “SRS”
warning lamp seven times, while performing tests on
the SRS.
Notes On System Check Chart
1. The “SRS” warning lamp should flash seven times after the ignition is first turned “ON”.
2.
After the “SRS” warning lamp flashes seven times, it
should turn to “LOCK”
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 “SRS” warning lamp is indicated. This test differentiates between ‘a
warning lamp stays “ON” condition’ and ‘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 ma
y
result in extended diagnostic time, incorrect diagnosis
and incorrect parts replacement.
SRS Diagnostic System Check
Step Action Yes No
1 Note the “SRS” warning lamp as the ignition switch is turned
“ON”.
Does the “SRS” warning lamp flash seven (7) times? Go to Step 2 Go to Step 3
2 Note the “SRS” warning lamp after it flashed 7 times.
Does the “SRS” warning lamp go “OFF”? Go to Step 4 Go to Step 5
3 Note the “SRS” warning lamp as the ignition switch is turned
“ON”.
Does the “SRS” warning lamp come “ON” steady? Go to Chart B. Go to Chart C.
4
1. Note the “SRS” warning lamp as the ignition switch is turned
“ON”.
Ignition switch is at “LOCK”.
2. Connect a scan tool to data link connector.
3. Follow direction given in the scan tool instruction manual.
Ignition switch is “ON”.
4. Request the SRS diagnostic trouble code display, recode all
history diagnostic trouble code(s), specifying as current or
history in repair order.
Is (are) diagnostic trouble code(s) displayed?
Ignition switch
“LOCK”.
W hen DTC B0071 is set, go to DTC B0071 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
malfunctions, no
further diagnosis is required.
If scan tool
indicated “NO DATA
RECEIVED,” refer to chassis
electrical section 8.
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
9A1-18 RESTRAINT CONTROL SYSTEM
DTC Will Clear When
Resistance value returns specified resistance value.
DTC Chart Test Description
Number(s) below refer to step number(s) on the
diagnostic chart:
2. This test determines whether the malfunction is in
the SRS control unit.
3. This test verifies proper connection of the yello
w
connector.
4. This test checks for proper contact and/or corrosion
of the yellow connector terminals.
5. This test checks for a malfunctioning passenger ai
r
bag assembly.
6. This test determines whether the malfunction is due
to a high resistance in the wiring.
Diagnostic Aids
An intermittent condition is likely to be caused by a poor
connection at the passenger air bag assembly harness
connector terminals “1” and “2”, SRS control unit
terminal “17” and “16”, or a poor wire to terminal
connection in circuits “Passenger Bag High” and
“Passenger Bag Low”. The test for this diagnostic
trouble code is only run while the “SRS” warning lamp is
performing the bulb check. W hen the scan tool “Clea
r
Codes” command is issued and the malfunction is still
present, the DTC will not reappear until the next ignition
cycle.
DTC B0015 (Flash Code 15) Passenger Air Bag Squib Circuit High Resistance
Step Action Yes No
1 W as the “SRS Diagnostic System Check” Performed?
Go to Step 2 Go to The “SRS
Diagnostic System Check”
2
1. Check the passenger air bag squib circuit for open.
2. If a problem is found, repair as necessary.
W as a problem found? Verify repair Go to Step 3
3
1. Ignition switch is at “LOCK”.
2. Make sure the passenger air bag assembly yellow connector
located behind the glove box assembly is seated properly.
Is the yellow connector connected properly? Go to Step 4 Seat passenger Air
Bag assembly
yellow connector properly.
Go to Step 7
4
1. Disconnect and inspect the passenger air bag assembly
yellow connector located behind the glove box assembly.
2. If OK, reconnect the passenger air bag assembly connector.
3. Ignition switch is “ON”.
Is DTC B0015 current? Go to Step 5 Go to Step 7
5
1. Ignition switch is at “LOCK”.
2. Disconnect the SRS coil and passenger air bag assembly,
yellow connector located at the base of the steering column
and behind the glove box assembly.
3. Connect a 5-8840-2421-0 SRS driver / passenger load tool
and appropriate adapters to the SRS coil and passenger air
bag assembly harness connectors.
4. Ignition switch is “ON”.
Is DTC B0015 Current? Go to Step 6 Ignition switch
“LOCK”.
Replace the
passenger air bag assembly.
Go to Step 7
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
RESTRAINT CONTROL SYSTEM 9A1-21
DTC Will Clear When
Resistance value returns to specified resistance value.
DTC Chart Test Description
Number(s) below refer to step number(s) on the
diagnostic chart:
2. This test determines whether the malfunction is in
the SRS control unit.
3. This test verifies connection of the yellow connector.
4. This test checks for proper operation of the shorting
clip on the yellow connector.
5. This test checks for a malfunctioning passenger ai
r
bag assembly.
6. This test determines whether the malfunction is due
to shortening in the wiring.
Diagnostic Aids
An intermittent condition is likely to be caused by a short
between circuits “Passenger Bag High” and “Passenge
r
Bag Low” or a malfunctioning shorting clip on the
passenger air bag assembly which would require
replacement of the air bag assembly. The test for this
diagnostic trouble code is only run while the “SRS”
warning lamp is performing the bulb check. W hen the
scan tool “Clear Codes” command is issued and the
malfunction is still present, the DTC will not reappea
r
until the next ignition cycle.
DTC B0016 (Flash Code 16) Passenger Air Bag Squib Circuit Low Resistance
Step Action Yes No
1 W as the “SRS Diagnostic System Check” performed?
Go to Step 2 Repeat the “SRS
Diagnostic System Check”
2
1. Check the passenger air bag squib circuit for short to voltage
or short to ground.
2. If a problem is found, repair as necessary.
W as a problem found? Verify repair Go to Step 3
3
1. Ignition switch is at “LOCK”.
2. Make sure the passenger air bag assembly yellow connector
located behind the glove box assembly is seated properly.
Is the yellow connector connected properly? Go to Step 4 Seat passenger air
bag assembly
yellow connector properly.
Go to Step 7
4
1. Disconnect and inspect the passenger air bag assembly
yellow connector located behind the glove box assembly.
2. If ok, reconnect the passenger air bag assembly connector.
3. Ignition switch is “ON”.
Is DTC B0016 Current? Go to Step 5 Go to Step 7
5
1. Ignition switch is at “LOCK”.
2. Disconnect the SRS coil and passenger air bag assembly
yellow connector located at the base of the steering column
and behind the glove box assembly.
3. Connect 5-8840-2421-0 SRS driver/passenger load tool and
appropriate adapters to the SRS coil and the passenger air
bag assembly harness connectors.
4. Ignition switch is “ON”.
Is DTC B0016 current? Go to Step 6 Ignition switch
“LOCK”.
Replace the
passenger air bag assembly.
Go to Step 7
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
9A1-24 RESTRAINT CONTROL SYSTEM
DTC Will Clear When
The “Passenger Bag Low" voltage comes to specified
voltage.
DTC Chart Test Description
Number(s) below refer to circled number(s) on the
diagnostic chart.
2. This test determines whether the SRS control unit is malfunctioning.
3. This test isolates the malfunction to one side of the passenger air bag assembly yellow connecto
r
behind the glove box compartment.
4. This test determines whether the malfunction is in
the “Passenger Bag High” circuit.
5. This test determines whether the malfunction is in the “Passenger Bag Low” circuit.
Diagnostic Aids
An intermittent condition is likely to be caused by a short
to ground/+B in the passenger air bag assembly circuit.
Inspect circuits “Passenger Bag High” and “Passenge
r
Bag Low” carefully for cutting or chafing. If the wiring
pigtail of the passenger air bag assembly is damaged,
the component must be replaced.
DTC B0018 (Flash Code 18) Passenger Air Bag Squib Circuit Short to GND
Step Action Yes No
1 W as the “SRS Diagnostic System Check” performed?
Go to Step 2 Go to the “SRS
Diagnostic System Check”
2 1. W hen measurements are requested in this chart use a 5-
8840-0366-0 DMM with a correct terminal adapter from 5-
8840-2835-0.
2. Ignition switch is at “LOCK”.
3. Ignition switch is “ON”.
4. Check the passenger air bag squib circuit for a short to ground.
W as a problem found? Go to Step 3
3 1. Ignition switch is at “LOCK”.
2. Disconnect the passenger air bag assembly yellow connector behind the glove box assembly.
3. Leave the driver air bag assembly connected.
4. Connect the SRS driver / passenger load tool 5-8840-2421-0 and appropriate adapter to the passenger air bag assembly
harness connector.
5. Ignition switch is “ON”.
Is DTC B0018 current? Go to Step 4 Ignition switch is at
“LOCK”.
Replace
passenger air bag assembly .
Go to Step 6
4 1. Ignition switch is at “LOCK”.
2. Disconnect the SRS driver /passenger load tool.
3. Measure the resistance on the SRS control unit harness connector as follow.
z From terminals "17" to "3" and "23" (ground) (without the
pretensioner)
z From terminals "17" to "3" and "15" (ground) (with the
pretensioner)
Does 5-8840-0366-0 display “OL” (Infinite)? Go to Step 5 Replace SRS
Harness.
Go to Step 6
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
RESTRAINT CONTROL SYSTEM 9A1-27
DTC Will Clear When
The SRS control unit is replaced and the “Passenger
Bag Low" voltage comes to specified voltage.
DTC Chart Test Description
Number(s) below refer to circled number(s) on the
diagnostic chart.
2. This test determines whether the SRS control unit is malfunctioning.
3. This test isolates the malfunction to one side of the passenger air bag assembly yellow connecto
r
behind the glove box compartment.
4. This test determines whether the malfunction is in the “Passenger Bag High” circuit.
5. This test determines whether the malfunction is in the “Passenger Bag Low” circuit.
Diagnostic Aids
An intermittent condition is likely to be caused by a short
to ground/+B in the passenger air bag assembly circuit.
Inspect circuits “Passenger Bag High” and “Passenge
r
Bag Low” carefully for cutting or chafing. If the wiring
pigtail of the passenger air bag assembly is damaged,
the component must be replaced.
DTC B0019 (Flash Code 19) Passenger Air Bag Squib Circuit Short to Battery Voltage
Step Action Yes No
1 W as the “SRS Diagnostic System Check” performed? Go to Step 2 Go to the “SRS
Diagnostic System Check”
2 1. W hen measurements are requested in this chart use a 5-
8840-0366-0 DMM with a correct terminal adapter from 5-
8840-2835-0.
2. Ignition switch is at “LOCK”.
3. Ignition switch is “ON”.
4. Check the passenger air bag squib circuit for a short to voltage, short to ground and open.
W as a problem found? Go to Step 3
―
3 1. Ignition switch is at “LOCK”.
2. Disconnect the passenger air bag assembly yellow connector behind the glove box assembly.
3. Leave the driver air bag assembly connected.
4. Connect the SRS driver /passenger load tool 5-8840-2421-0 and appropriate adapter to the passenger air bag assembly
harness connector.
5. Ignition switch is “ON”.
Is DTC B0019 current? Go to Step 4 Ignition switch is at
“LOCK”.
Replace
passenger air bag assembly
Go to Step 6
4 Measure the resistance on the SRS control unit harness connector from terminal “17” to terminal “1” (ignition).
Does 5-8840-0366-0 display “OL” (Infinite)? Go to Step 5 Replace SRS
Harness.
Go to Step 6
5 Measure the resistance on the SRS control unit harness connector from terminal “16” to terminal “1” (ignition).
Does 5-8840-0366-0 display “OL” (Infinite)? Go to Chart A Replace SRS
Harness.
Go to Step 6
6 1. Reconnect all the components and ensure all components
are properly mounted.
2. Clear diagnostic trouble codes.
Is this step finished? Go to the “SRS
Diagnostic system Check” ―
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007