Circuit ISUZU KB P190 2007 Workshop Repair Manual
[x] Cancel search | Manufacturer: ISUZU, Model Year: 2007, Model line: KB P190, Model: ISUZU KB P190 2007Pages: 6020, PDF Size: 70.23 MB
Page 5710 of 6020
9A1-28 RESTRAINT CONTROL SYSTEM
DTC B0021 (Flash Code 21) Driver Air Bag 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”. “Driver Bag Low”
terminal “13” is grounded through a current sink and the
driver current source connected to “Driver Bag High”
terminal “14” allows a known amount of current to flow.
By monitoring the voltage difference between “Drive
r
Bag High” and “Driver Bag Low”, the SRS control unit
calculates the combined resistance of the driver air bag
assembly, SRS coil assembly, harness wiring circuits
“Driver Bag High” and “Driver Bag Low” and connecto
r
terminal contact.
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ISUZU KB P190 2007
Page 5711 of 6020
RESTRAINT CONTROL SYSTEM 9A1-29
DTC Will Set When
The combined resistance of the driver air bag
assembly, the SRS Coil assembly, the harness wiring
circuits “Driver Bag High” and “Driver Bag Low”, and
connector terminal contact is above a specified value.
This test runs once for 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
The SRS control unit turns “ON” the “SRS” warning
lamp and sets DTC B0021.
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 proper connection of the yello
w
connector at the base of the steering column.
4. This test checks for proper contact and/or corrosion
of the connector terminals at the base of the steering
column.
5. This test isolates the malfunction to one side of the
SRS coil assembly yellow connector located at the
base of the steering column.
6. This test determines whether the malfunction is due
to high resistance in the wiring.
7. 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 poor
connection at terminals “1” and “2” of the SRS coil
connector at the base of the steering column, terminal
“1” and “2” of the driver air bag assembly connector at
the top of the steering column, the SRS control unit
terminals “14” and “13” or a poor wire to terminal
connection in circuit “Driver Bag High” or “Driver Bag
Low” The test for this diagnostic trouble code is only run
while the “SRS” 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.
DTC B0021 (Flash Code 21) Driver Air Bag Squib Circuit High Resistance
Step Action Yes No
1 Perform the “SRS Diagnostic System Check”.
W as the “SRS Diagnostic System Check” performed? Go to Step 2 Repeat the “SRS
Diagnostic System Check”
2
1. Check the driver air bag squib circuit for open.
2. If a the problem is found, repair as necessary.
W as a problem found? Verify repair Go to Step 3
3
1. Ignition switch to “LOCK”.
2. Disconnect the SRS coil assembly yellow connector located
at the base of the steering column and check it is seated
properly.
Is the connector connected properly? Go to Step 4 Seat SRS coil
assembly
connector properly. Go to Step 8
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ISUZU KB P190 2007
Page 5712 of 6020
9A1-30 RESTRAINT CONTROL SYSTEM
Step Action Yes No
4
1. Disconnect and inspect the SRS coil assembly yellow
connector located at the base of the steering column.
2. If ok, reconnect the SRS coil assembly yellow connector.
3. Ignition switch is “ON”.
Is DTC B0021 current? Go to Step 5 Go to Step 8
5
1. Ignition switch is at “LOCK”.
2. Disconnect the SRS coil and the passenger air bag assembly,
yellow 2–pin 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 the passenger
air bag assembly harness connectors.
4. Ignition switch is “ON”.
Is DTC B0021 current? Go to Step 6 Go to Step 7
6
1. Ignition switch is at “LOCK“.
2. There has been an increase 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
SRS coil assembly harness connector.
3. Connect the SRS driver / passenger load tool 5-8840-2421-0 on the top of the steering column.
4. Reconnect the SRS coil assembly harness connector at the
base of the steering column.
5. Ignition switch is “ON”.
Is DTC B0021 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? Repeat the “SRS
Diagnostic System Check” ―
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ISUZU KB P190 2007
Page 5713 of 6020
RESTRAINT CONTROL SYSTEM 9A1-31
DTC B0022 (Flash Code 22) Driver Air Bag 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”. “Driver Bag Low”
terminal “13” is grounded through a current sink and the
driver current source connected to “Driver Bag High”
terminal “14” allows a known amount of current to flow.
By monitoring the voltage difference between “Drive
r
Bag High” and “Driver Bag Low” the SRS control unit
calculates the combined resistance of the driver air bag
assembly, SRS coil assembly, harness wiring circuits
“Driver Bag High” and “Driver Bag Low” and connecto
r
terminal contact.
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TO MODEL INDEX
ISUZU KB P190 2007
Page 5714 of 6020
9A1-32 RESTRAINT CONTROL SYSTEM
DTC Will Set When
The combined resistance of the driver air bag
assembly, SRS Coil assembly, harness wiring circuits
“Driver Bag High” and “Driver Bag Low”, and connecto
r
terminal contact is above a specified value. This test is
run once for 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
The SRS control unit turns “ON” the “SRS” warning
lamp and sets DTC B0022.
DTC Will Clear When
Resistance value returns to specified resistance value.
DTC Chart Test Description
Number(s) below refer to circled 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 at the base of the steering column.
4. This test checks for proper operation of the shorting
clip in the yellow connector.
5. This test isolates the malfunction to one side of the
SRS coil assembly yellow connector located at the
base of the steering column.
6. This test determines whether the malfunction is due
to shortening in the wiring.
7. 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
between circuit “Driver Bag High” or “Driver Bag Low”
and a malfunctioning shorting clip on the driver air bag
assembly or the SRS coil assembly which would require
replacement of the component. 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 B0022 (Flash Code 22) Driver Air Bag Squib Circuit Low Resistance
Step Action Yes No
1 Perform the “SRS Diagnostic System Check.”
W as the “SRS Diagnostic System Check” performed? Go to Step 2 Go to the “SRS
Diagnostic System Check”
2
1. Check the driver 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 to “LOCK”.
2. Make sure the SRS coil assembly yellow connector located at
the base of steering column is seated properly.
Is the connector connected properly? Go to Step 4 Seat driver air bag
assembly
connector properly. Go to Step 8
4
1. Disconnect and inspect the SRS coil assembly yellow
connector located at the base of the steering column.
2. If ok, reconnect the SRS coil assembly yellow connector.
3. Ignition switch is “ON”.
Is DTC B0022 current? Go to Step 5 Go to Step 8
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ISUZU KB P190 2007
Page 5715 of 6020
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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ISUZU KB P190 2007
Page 5716 of 6020
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
Page 5717 of 6020
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
Page 5719 of 6020
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
Page 5720 of 6020
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