2007 ISUZU KB P190 Circuit

RESTRAINT CONTROL SYSTEM 9A1-37

DTC B0026 (Flash Code 26) Driver Air Bag Squib Circuit Short to Battery
Voltage



RTW 79ALF000301

Circuit Description
W hen the ignition switch is turned “ON”, the SRS
control unit will perform tests to diagnose critical
malfunctions within itself. Upon passing these tests,
“Ignition 1”, and deployment loop voltages are
measured to ensure they are within their respective
normal voltage ranges.
The SRS control unit monitors the voltage at “Drive
r
Bag Low” terminal “13” and “Passenger Bag Low”
terminal “16” to detect shorts to ground/+B in the air bag
assembly circuits.

DTC Will Set When
“Ignition 1" is in the normal operating voltage range.
The voltage at “Driver Bag Low" is above a specified
value,
DTC B0026 will set.

Action Taken
The SRS control unit turns “ON” the “SRS” warning
lamp and sets a diagnostic trouble code.

DTC Will Clear When
The SRS control unit is replaced and the “Driver Bag
Low" voltage comes to specified voltage.

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ISUZU KB P190 2007

9A1-38 RESTRAINT CONTROL SYSTEM

DTC Chart Test Description
Number(s) below refer to step 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 SRS coil assembly yellow 2–pin connector at the
base of the steering column.
4. This test determines whether the malfunction is in the “Driver Bag High” circuit.
5. This test determines whether the malfunction is in the “Driver Bag Low” circuit.
6. This test determines whether the malfunction is in the SRS coil assembly or the driver air bag
assembly.
Diagnostic Aids
An intermittent condition is likely to be caused by a short
to ground/+B in the driver air bag assembly circuit.
Inspect circuits “Driver Bag High” and “Driver Bag Low”
carefully for cutting or chafing.


DTC B0026 (Flash Code 26) Driver 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 driver air bag squib circuit for short to voltage or short to ground and open.
W as a problem found? Go to Step 3

3 1. Ignition switch is at “LOCK”.
2. Disconnect the SRS coil assembly yellow connector located at base of the steering column. Leave the passenger air bag
assembly connected.
3. Connect the SRS driver /passenger load tool 5-8840-2421-0 and appropriate adapter to the SRS coil assembly harness
connector.
4. Ignition switch is “ON”.
Is DTC B0026 current? Go to Step 4 Go to Step 6
4
Measure resistance on SRS control unit harness connector from
terminal “14” to terminal “1” (ignition).
Does 5-8840-0366-0 display “OL” (infinite)? Go to Step 5
Replace SRS
harness.
Go to Step 7
5 Measure the resistance on the SRS control unit harness
connector from terminal “13” to terminal “1” (ignition).
Does 5-8840-0366-0 display “OL” (infinite)? Go to Chart A Replace SRS
harness.
Go to Step 7

BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007

9A1-40 RESTRAINT CONTROL SYSTEM

DTC B0029 (Flash Code 29) Passenger Pretensioner Squib Circuit High
Resistance



RTW 79ALF000301

Circuit Description
W hen the ignition switch is turned “ON”, the SRS
control unit will perform tests to diagnose critical
malfunctions within itself. Upon passing these tests
“Ignition 1”, and deployment loop voltages are
measured to ensure they are within their respective
normal voltage ranges. The SRS control unit then
proceeds with the “Resistance Measurement Test”.
“Passenger Pretensioner Low” terminal “10” is
grounded through a resister and the passenger current
source connected to “Passenger Pretensioner High”
terminal “11” allows a known amount of current to flow.

By monitoring the voltage difference between
“Passenger Pretensioner High” and “Passenger
Pretensioner Low” the SRS control unit calculates the
combined resistance of the passenger pretensione
r
assembly, harness wiring circuits “Passenger
Pretensioner High” and “Passenger Pretensioner Low”
connector terminal contact.


BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007

RESTRAINT CONTROL SYSTEM 9A1-41

DTC Will Set When
The combined resistance of the passenger air
pretensioner assembly, harness wiring circuits
“Passenger Pretensioner High” and “Passenge
r
Pretensioner Low”, and connector terminal contact is
above a specified value. This test is run once each
ignition cycle during the “Resistance Measurement
Test” when:
1. No “higher priority faults” are detected during “Turn–
ON”,
2. “Ignition 1” voltage is in the specified value.

Action Taken
SRS control unit turns “ON” the “AIR BAG” warning
lamp and sets a diagnostic trouble code.

DTC Will Clear When
The ignition switch is at “LOCK”.

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. The test checks for a malfunctioning passenge
r
pretensioner assembly.
6. This test determines whether the malfunction is due
to high resistance in the wiring.

Diagnostic Aids

An intermittent condition is likely to be caused by a poor
connection at the passenger pretensioner assembly
harness connector terminals “1” and “2”, SRS control
unit terminal “11” and “10”, or a poor wire to terminal
connection in circuits “Passenger Pretensioner High”
and “Passenger Pretensioner Low”. This test for this
diagnostic trouble code is only run while the “AIR BAG”
warning lamp is performing the bulb check. W hen a
scan tool “Clear Codes” command is issued and the
malfunction is still present, the DTC will not reappea
r
until the next ignition cycle.



BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007

9A1-42 RESTRAINT CONTROL SYSTEM

DTC B0029 (Flash Code 29) Passenger Pretensioner 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 pretensioner circuit for open.
2. If the problem 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 at the base of the passenger seat.
Is the yellow connector connected properly? Go to Step 4 Seat passenger
pretensioner
assembly yellow connector properly.
Go to Step 7
4
1. Disconnect and inspect the passenger pretensioner assembly
yellow connector located at the base of the passenger seat.
2. If ok, reconnect the passenger pretensioner assembly
connector.
3. Ignition switch “ON”.
Is DTC B0029 current? Go to Step 5 Go to Step 7
5

1. Ignition switch is at “LOCK”.
2. Disconnect passenger pretensioner assembly, yellow
connector located at the base of the passenger seat.
3. Connect 5-8840-2421-0 SRS driver / passenger load tool and
appropriate adapters to passenger pretensioner assembly
harness connectors.
4. Ignition switch “ON”.
Is DTC B0029 Current? Go to Step 6 Ignition switch is at
“LOCK.”
Replace the passenger
pretensioner assembly.
Go to Step 7
6
1. Ignition switch is at “LOCK”.
2. There has been an increase in the total circuit resistance of
the passenger loop.
3. Use the high resolution ohmmeter mode of the DVM while
checking circuits “Pasenger Pretensioner High” and
“Passenger Pretensioner Low”, and SRS control unit
connector terminal “11” and “10” to locate the root cause.
W as a fault found? Replace SRS
harness or repair chassis harness. Go to Step 7 Go to Chart A
7

1. Reconnect all components ensure all component are properly
mounted.
2. Clear diagnostic trouble codes.
W as This step finished? Repeat the “SRS
Diagnostic System Check” ―



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TO MODEL INDEX
ISUZU KB P190 2007

RESTRAINT CONTROL SYSTEM 9A1-43

DTC B0031 (Flash Code 31) Passenger Pretensioner Squib Circuit Low
Resistance



RTW 79ALF000301

Circuit Description
W hen the ignition switch is turned “ON”, the SRS
control unit will perform tests to diagnose critical
malfunctions within itself. Upon passing these tests
“Ignition 1”, and deployment loop voltages are
measured to ensure they are within their respective
normal voltage ranges. The SRS control unit then
proceeds with the “Resistance Measurement Test”.
“Passenger Pretensioner Low” terminal “10” is
grounded through a resistor and the passenger current
source connected to “Passenger Pretensioner High”
terminal “11” allows a known amount of current to flow.

By monitoring the voltage difference between
“Passenger Pretensioner High” and “Passenger
Pretensioner Low”, the SRS control unit calculates the
combined resistance of the passenger air bag
assembly, harness wiring circuits “Passenge
r
Pretensioner High” and “Passenger Pretensioner Low”
connector terminal contact.



BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007

9A1-44 RESTRAINT CONTROL SYSTEM

DTC Will Set When
The combined resistance of the passenger pretensioner
assembly, harness wiring circuits “Passsenger
Pretensioner High” and “Passenger Pretensioner Low”,
and connector terminal contact is above a specified
value. This test is run once each ignition cycle during
the “Resistance Measurement Test” when:
1. No “higher priority faults” are detected during “Turn–
ON”,
2. “Ignition 1” voltage is in the specified value.

Action Taken
SRS control unit turns “ON” the “AIR BAG” warning
lamp and sets a diagnostic trouble code.

DTC Will Clear When
The ignition switch is turned “LOCK”.

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 cheeks for proper operation of the shorting
clip in the yellow connector.
5. The test checks for a malfunction passenge
r
pretensioner assembly.
6. This test determines whether the malfunctioning is
due to shortening in the wiring.

Diagnostic Aids

An intermittent condition is likely to be caused by a short
between circuits “Passenger Pretensioner High” and
“Passenger Pretensioner Low” or a malfunctioning
shorting clip on the passenger pretensioner assembl
y
which would require replacement of the pretensione
r
assembly. The test for this diagnostic trouble code is
only run while “AIR BAG” warning lamp is performing
the bulb check. W hen a scan tool “Clear Codes”
command is issued and the malfunction is still present,
the DTC will not reappear until the next ignition cycle.


BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007

RESTRAINT CONTROL SYSTEM 9A1-45

DTC B0031 (Flash Code 31) Passenger Pretensioner 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 pretensioner squib circuit for short to
valtage or short to ground.
2. If the broblem 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 at the base of the passenger seat.
Is the yellow connector connected properly? Go to Step 4 Seat passenger
pretensioner
assembly yellow connector properly.
Go to Step 7
4
1. Disconnect and inspect the passenger air bag assembly
yellow connector located at the base of the passenger seat.
2. If ok, reconnect the passenger air bag assembly connector.
3. Ignition switch is at “ON”.
Is DTC B0031 Current? Go to Step 5 Go to Step 7
5

1. Ignition switch is at “LOCK”.
2. Disconnect SRS coil and passenger pretensioner assembly,
yellow connector located at the base of the passenger seat.
3. Connect 5-8840-2421-0 SRS driver/passenger load tool and
appropriate adapters to passenger pretensioner assembly
harness connectors.
4. Ignition switch is at “ON”.
Is DTC B0031 current? Go to Step 6 Ignition switch is at
“OFF”.
Replace the passenger
pretensioner assembly.
Go to Step 7
6
1. Ignition switch is at “LOCK”.
2. There has been a decrease in the total circuit resistance of
the passenger inflator deployment loop.
3. Use the high resolution ohmmeter mode of the DVM while checking circuits “Passenger pretensioner High” and
“Passenger Pretensioner Low”, and SRS control unit
connector terminal “11” and “10” to locate the root cause.
W as a fault found? Replace SRS
harness or repair chassis harness. Go to Step 7 Go to Chart A
7

1. Reconnect all components, ensure all component are
properly mounted.
2. Clear diagnostic trouble codes.
W as this step finished? Repeat the “SRS
Diagnostic System Check” ―



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007