ignition ISUZU TF SERIES 2004 Owner's Guide

RESTRAINT CONTROL 9A1-25

Step Action Yes No
6 Measure resistance on SRS control unit harness connector from
terminal “48” to terminal “35” (ignition).
Does 5-8840-0285-0 display “OL” (Infinite)? Go to Step 7
Replace SRS
Harness.
Go to Step 8
7 Measure resistance on SRS control unit harness connector from
terminal “47” to terminal “35” (ignition).
Does 5-8840-0285-0 display “OL” (Infinite)? Go to Chart A Replace SRS
Harness.
Go to Step 8
8

1. Reconnect all components and ensure all component are
properly mounted.

2. Clear diagnostic trouble codes.
Was this step finished? Go to the “SRS
Diagnostic system
Check” Go to Step 8

9A1-26 RESTRAINT CONTROL SYSTEM

DTC B0022 (Flash Code 22) Driver Airbag Squib Circuit Low Resistance


RTW49JLF000101

Circuit Description
When 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 “46” is grounded through a current sink and
the driver current source connected to “Driver Bag
High” terminal “45” allows a known amount of current to
flow. By monitoring the voltage difference between
“Driver Bag High” and “Driver Bag Low” the SRS control
unit calculates the combined resistance of the driver ai
r
bag assembly, SRS coil assembly, harness wiring
circuits “Driver Bag High” and “Driver Bag Low” and
connector terminal contact.

RESTRAINT CONTROL 9A1-27

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 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 DTC B0022.

DTC Will Clear When
The ignition switch is turned “OFF.”
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 yellow
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 isolate the malfunction to one side of the
SRS coil assembly yellow connector located at the
base of 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”
or a malfunctioning shorting clip on the driver air bag
assembly or SRS coil assembly which would require
replacement of the component. The test for this
diagnostic trouble code is only run while the “AIR BAG”
warning lamp is performing the bulb check. When 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 B0022 (Flash Code 22) Driver Airbag Squib Circuit Low Resistance

Step Action Yes No
1 Perform the “SRS Diagnostic System Check.”
Was 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 the problem found, repair as necessary.
Was a problem found? Verify repair Go to Step 3
3

1. Ignition switch “OFF.”

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 base of steering column.

2. If ok, reconnect the SRS coil assembly yellow connector.

3. Ignition switch “ON.”
Is DTC B0022 current? Go to Step 5 Go to Step 8

9A1-28 RESTRAINT CONTROL SYSTEM

Step Action Yes No
5

1. Ignition switch “OFF.”

2. Disconnect SRS coil and passenger air bag assembly, yellow
connector located at the base of steering column and behind
the glove box assembly.

3. Connect SRS driver / passenger load tool 5-8840-2421-0 and
appropriate adapter to SRS coil and passenger air bag
assembly harness connectors.

4. Ignition switch “ON.”
Is DTC B0022 current? Go to Step 6 Go to Step 7
6

1. Ignition switch “OFF.”

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 DVM while
checking circuits “Driver Bag High” and “Driver Bag Low”,
and SRS control unit connector terminal “45” and “46” to
locate the root cause.
Was a fault found? Replace SRS
harness.
Go to Step 8 Go to Chart A
7

1. Ignition switch “OFF.”

2. Disconnect SRS driver / passenger load tool from driver air
bag assembly harness connector.
3. Connect SRS driver / passenger load tool 5-8840-2421-0 to
the top of steering column connector.

4. Reconnect SRS coil assembly harness connector as the base
of steering column.

5. Ignition switch “ON.”
Is DTC B0022 current? Ignition switch
“off.”
Replace SRS coil
assembly.
Go to Step 8 Ignition switch
“OFF.”
Replace driver air
bag assembly.
Go to Step 8
8

1. Reconnect all components, ensure all component are
properly mounted.

2. Clear diagnostic trouble codes.
Was this step finished? Go to the “SRS
Diagnostic System
Check” Go to Step 8

RESTRAINT CONTROL 9A1-29

DTC B0024 (Flash Code 24) Driver Airbag Squib Circuit Voltage
Range/Performance


RTW49JLF000101
Circuit Description
When 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 “46” and “Passenger Bag Low”
terminal “47” to detect shorts to ground/+B in the air bag
assembly circuits.


DTC Will Set When
Neither of the two air bag assemblies is open.
“Ignition 1” is within the normal operating voltage range.
This test is run once each ignition cycle and
“Continuous Monitoring”. Once these conditions are
met and the voltage at “Driver Bag Low” is out of a
specified value, DTC B0024 will set.

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

DTC Will Clear When
The malfunction is no longer occurring and the ignition
is turned “OFF”.

9A1-30 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
“Driver Bag High” circuit.
5.
This test determines whether the malfunction is in
“Driver Bag Low” circuit.
6.
This test determines whether the malfunction is in
“Driver Bag High” circuit.
7.
This test determines whether the malfunction is in
“Driver Bag Low” circuit.
8.
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 B0024 (Flash Code 24) Driver Airbag Squib Circuit Voltage Range/Performance

Step Action Yes No
1 Was the “SRS Diagnostic System Check” performed? Go to Step 2 Go to the “SRS
Diagnostic System
Check”
2

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. Ignition switch “ON.”

4. Check the driver air bag squib circuit for short to voltage or
short to ground and open.
Was a problem found? Go to Step 3


3

1. Ignition switch “OFF.”

2. Disconnect SRS coil assembly yellow connector located at
base of the steering column. leave passenger air bag
assembly connected.

3. Connect SRS driver / passenger load tool 5-8840-2421-0 and
appropriate adapter to SRS coil assembly harness
connector.

4. ignition switch “ON.”
Is DTC B0024 current? Go to Step 4 Go to Step 8
4

1. Ignition switch “OFF.”

2. Disconnect SRS control unit.
3. Disconnect SRS driver / passenger load tool.

4. Measure resistance on SRS control unit harness connector
“45” to terminal “40” (ground).
Does 5-8840-0285-0 display “OL” (infinite)? Go to Step 5 Replace SRS
harness.
Go to Step 9
5 Measure resistance on SRS control unit harness connector from
terminal “46” to terminal “40” (ground).
Does 5-8840-0285-0 display “OL” (infinite)? Go to Step 6
Replace SRS
harness.
Go to Step 9

RESTRAINT CONTROL 9A1-31

Step Action Yes No
6 Measure resistance on SRS control unit harness connector from
terminal “45” to terminal “35” (ignition).
Does 5-8840-0285-0 display “OL” (infinite)? Go to Step 7
Replace SRS
harness.
Go to Step 9
7 Measure resistance on SRS control unit harness connector from
terminal “46” to terminal “35” (ignition).
Does 5-8840-0285-0 display “OL” (infinite)? Go to Chart A
Replace SRS
harness.
Go to Step 9
8

1. Ignition switch “OFF.”

2. Disconnect SRS driver / passenger load tool 5-8840-2421-0
from SRS coil assembly harness connector.

3. Connect SRS driver / passenger load tool 5-8840-2421-0 and
appropriate adapter to driver air bag assembly harness
connector. located top of the steering column connector.

4. Reconnect SRS coil assembly harness connector as the base
of steering column.

5. Ignition switch “ON.”
Is DTC B0024 current? Ignition switch
“OFF.”
Replace SRS coil
assembly.
Go to Step 9 Ignition switch
“OFF.”
Replace driver air
bag assembly.
Go to Step 9
9

1. Reconnect all components ensure all component are properly
mounted.

2. Clear diagnostic trouble codes.
Was this step finished? Go to the “SRS
Diagnostic System
Check” Go to Step 9

9A1-32 RESTRAINT CONTROL SYSTEM

DTC B0026 (Flash Code 26) Driver Airbag Squib Circuit High Resistance


RTW49JLF000101

Circuit Description
When 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 “46” is grounded through a current sink and the
driver current source connected to “Driver Bag High”
terminal “45” 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.

RESTRAINT CONTROL 9A1-33

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 connector
terminal contact is above a specified value. This test
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 DTC B0026.

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



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 yellow
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 steering
column.
5.
This test isolate 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, SRS control unit
terminals “45” and “46” or a poor wire to terminal
connection in circuit “Driver Bag High” or “Driver Bag
Low” The test for this diagnostic trouble code is onl
y
run while the “AIR BAG” warning lamp is performing
the bulb check. When 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 B0026 (Flash Code 26) Driver Airbag Squib Circuit High Resistance

Step Action Yes No
1 Perform the “SRS Diagnostic System Check”.
Was 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 the problem found, repair as necessary.
Was a problem found? Verify repair Go to Step 3
3

1. Ignition switch “OFF.”

2. Disconnect SRS coil assembly yellow connector located at
base of steering column is seated properly.
Is the connector connected properly? Go to Step 4 Seat SRS coil
assembly
connector
properly.
Go to Step 8

9A1-34 RESTRAINT CONTROL SYSTEM

Step Action Yes No
4

1. Disconnect and inspect the SRS coil assembly yellow
connector located base of steering column.

2. If ok, reconnect the SRS coil assembly yellow connector.
3. Ignition switch “ON.”
Is DTC B0026 current? Go to Step 5 Go to Step 8
5

1. Ignition switch “OFF.”

2. Disconnect SRS coil and passenger air bag assembly, yellow
2–pin connector located at the base of steering column and
behind the glove box assembly.

3. Connect SRS driver / passenger load tool 5-8840-2421-0 and
appropriate adapter to SRS coil and passenger air bag
assembly harness connectors.

4. Ignition switch “ON.”
Is DTC B0026 current? Go to Step 6 Go to Step 7
6

1. Ignition switch “Off. “

2. There has been a increase in the total circuit resistance of
the driver deployment loop.

3. Use the high resolution ohmmeter mode of the DVM while
checking circuits “Driver Bag High” and “Driver Bag Low”,
and SRS control unit connector terminal “45” and “46” to
locate the root cause.
Was a fault found? Replace SRS
harness.
Go to Step 8 Go to Chart A
7

1. Ignition switch “OFF.”

2. Disconnect SRS driver / passenger load tool from SRS coil
assembly harness connector.
3. Connect SRS driver / passenger load tool 5-8840-2421-0 on
the top of steering column.

4. Reconnect SRS coil assembly harness connector as the base
of steering column.

5. Ignition switch “ON.”
Is DTC B0026 current? Ignition switch
“OFF.”
Replace SRS coil
assembly.
Go to Step 8 Ignition switch
“OFF.”
Replace driver air
bag assembly.
Go to Step 8
8

1. Reconnect all components ensure all component are
properly mounted.

2. Clear diagnostic trouble codes.
Was this step finished? Repeat the “SRS
Diagnostic System
Check” Go to Step 8