2007 ISUZU KB P190 ignition

RESTRAINT CONTROL SYSTEM 9A1-33

Step Action Yes No
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 the SRS driver / passenger load tool 5-8840-2421-0 and appropriate adapter to the SRS coil and passenger air
bag assembly harness connectors.
4. Ignition switch is “ON”.
Is DTC B0022 current? Go to Step 6 Go to Step 7
6

1. Ignition switch to “LOCK”.
2. There has been a decrease in the total circuit resistance of
the driver deployment loop.
3. Use the high resolution ohmmeter mode of the DMM while
checking circuits “Driver Bag High” and “Driver Bag Low”, and
the SRS control unit connector terminal “14” and “13” to
locate the root cause.
W as a fault found? Replace SRS
harness.
Go to Step 8 Go to Chart A
7

1. Ignition switch is at “LOCK”.
2. Disconnect the SRS driver / passenger load tool from the
driver air bag assembly harness connector.
3. Connect the SRS driver / passenger load tool 5-8840-2421-0 to the top of the steering column connector.
4. Reconnect the SRS coil assembly harness connector at the
base of the steering column.
5. Ignition switch is “ON”.
Is DTC B0022 current? Ignition switch
“LOCK”.
Replace SRS coil assembly.
Go to Step 8 Ignition switch
“LOCK”.
Replace driver air bag assembly. Go to Step 8
8
1. Reconnect all components and ensure all components are
properly mounted.
2. Clear the diagnostic trouble codes.
Is this step finished? Go to the “SRS
Diagnostic System Check” ―



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TO MODEL INDEX
ISUZU KB P190 2007

9A1-34 RESTRAINT CONTROL SYSTEM

DTC B0025 (Flash Code 25) Driver Air Bag Squib Circuit Short to GND




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 within the normal operating voltage range.
The voltage at “Driver Bag Low" is below a specified
value DTC B0025 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 “Driver Bag Low" voltage comes to specified
voltage.


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ISUZU KB P190 2007

RESTRAINT CONTROL SYSTEM 9A1-35

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 B0025 (Flash Code 25) Driver 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 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 B0025 current? Go to Step 4 Go to Step 6
4
1. Ignition switch is at “LOCK”.
2. Disconnect the SRS control unit.
3. Disconnect the SRS driver /passenger load tool.
4. Measure the resistance on the SRS control unit harness connector as follow.
z From terminals "14" to "3" and "23" (ground) (without the
pretensioner)
z From terminals "14" to "3" and "15" (ground) (with the
pretensioner and the passenger air bag)
z From terminals "14" to "3", "12" and "15" (ground) (with
the pretensioner and without the passenger air bag)
Does 5-8840-0366-0 display “OL” (infinite)? Go to Step 5 Replace SRS
harness.
Go to Step 7

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ISUZU KB P190 2007

9A1-36 RESTRAINT CONTROL SYSTEM

Step Action Yes No
5 Measure the resistance on the SRS control unit harness
connector as follow.
z From terminals "13" to "3" and "23" (ground) (without the
pretensioner)
z From terminals "13" to "3" and "15" (ground) (with the
pretensioner and the passenger air bag)
z From terminals "13" to "3", "12" and "15" (ground) (with
the pretensioner and without the passenger air bag)
Does 5-8840-0366-0 display “OL” (infinite)? Go to Chart A Replace SRS
harness.
Go to Step 7
6 1. Ignition switch is at “LOCK”.
2. Disconnect the SRS driver /passenger load tool 5-8840-2421- 0 from the SRS coil assembly harness connector.
3. Connect the SRS driver /passenger load tool 5-8840-2421-0 and appropriate adapter to the driver air bag assembly
harness connector. located at top of the steering column
connector.
4. Reconnect the SRS coil assembly harness connector at the base of the steering column.
5. Ignition switch is “ON”.
Is DTC B0025 current? Ignition switch is at
“LOCK”.
Replace SRS coil assembly.
Go to Step 7 Ignition switch is at
“LOCK”.
Replace driver air bag assembly. Go to Step 7
7 1. Reconnect all components and ensure all components are
properly mounted.
2. Clear the diagnostic trouble codes.
Is this step finished? Go to the “SRS
Diagnostic System Check” ―



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TO MODEL INDEX
ISUZU KB P190 2007

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.

BACK TO CHAPTER INDEX TO MODEL INDEX
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

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ISUZU KB P190 2007

RESTRAINT CONTROL SYSTEM 9A1-39

Step Action Yes No
6 1. Ignition switch is at “LOCK”.
2. Disconnect the SRS driver /passenger load tool 5-8840-2421- 0 from the SRS coil assembly harness connector.
3. Connect the SRS driver /passenger load tool 5-8840-2421-0 and appropriate adapter to the driver air bag assembly
harness connector. located at top of the steering column
connector.
4. Reconnect the SRS coil assembly harness connector at the base of the steering column.
5. Ignition switch is “ON”.
Is DTC B0026 current? Ignition switch is at
“LOCK”.
Replace SRS coil assembly.
Go to Step 7 Ignition switch is at
“LOCK”.
Replace driver air bag assembly. Go to Step 7
7 1. Reconnect all components and ensure all components are
properly mounted.
2. Clear the diagnostic trouble codes.
Is this step finished? Go to the “SRS
Diagnostic System Check” ―



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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