2002 ISUZU AXIOM Service Repair Manual

9J1±23
RESTRAINT CONTROL SYSTEM
DTC 19 Passenger Deployment Loop Short To Voltage
D09R200001
Circuit Description:
When the ignition switch is turned ªONº, the SDM will
perform tests to diagnose critical malfunctions within
itself. Upon passing these tests, ªignition 1º, and
deployment loop voltages are measured to ensure they
are within their respective normal voltage ranges.
The SDM monitors the voltages at ªDriver Bag Lowº
terminal ª4º and ªPassenger Bag Lowº terminal ª16º to
detect short to B+ in the air bag assembly circuits.
DTC Will Set When:
ªIgnition 1º is within the normal operating voltage range.
Once these conditions are met and the voltage at
ªPassenger Bag Lowº is above a specified value, DTC 19
will set. This test is run once each ignition cycle and
ªContinuous Monitoringº.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets
DTC 19 and also DTC 71.
DTC Will Clear When:
The SDM is replaced.
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 SDM.
3. This test isolates the malfunction to one side of the
passenger air bag assembly yellow 2±pin connector
behind glove box compartment.
4. This test determines whether the malfunction is in
CKT IB07±YEL/GRN.

RESTRAINT CONTROL SYSTEM 9J1±24
5. This test determines whether the malfunction is in
CKT IB08±YEL/RED.
Diagnostic Aids:
An intermittent condition is likely to be caused by a short
to B+ in the passenger air bag assembly circuit. Inspect
CKTs IB07±YEL/GRN and IB08±YEL/RED carefully forcutting or chafing. If the wiring pigtail of the passenger air
bag assembly is damaged, the component must be
replaced. A careful inspection of CKT IB07±YEL/GRN
and IB08±YEL/RED, including the passenger air bag
assembly pigtail is essential to ensure that the
replacement SDM will not be damaged.
DTC 19 Passenger Deployment Loop Short To Voltage
CAUTION: When DTC 19 has been set, it is necessary to replace the SDM. Setting DTC 19 and 25 or 51 or 53
will also cause DTC 71 to set. When a scan tool ªCLEAR CODESº command is issued and the malfunction
is no longer present, DTC 71 will remain current. Ensure that the short to voltage condition is repaired prior
to installing a replacement SDM to avoid damaging the SDM.
Step
ActionYe sNo
1Was the ªSRS Diagnostic System Checkº performed?
Go to Step 2
Go to the ªSRS
Diagnostic
System Check.º
21. When measurements are requested in this chart use J±39200
DVM with correct terminal adapter from J±35616±A.
2. Ignition switch ªOFF.º
3. Connect scan tool data link connector. Follow directions as
given in the scan tool operator's manual.
4. Ignition switch ªON.º
5. Read passenger sense LO.
Is passenger sense LO more than 3.5 volts?
Go to Step 3 Go to Chart A .
31. Ignition switch ªOFF.º
2. Disconnect passenger air bag assembly yellow 2±pin
connector behind the glove box assembly.
3. Leave driver air bag assembly connected.
4. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter to passenger air bag assembly harness
connector.
5. Ignition switch ªON.º
Is passenger sense LO more than 3.5 volts?
Go to Step 4
Ignition switch
ªOFF.º
Replace
passenger air
bag assembly.
Go to
Step 6
41. Ignition switch ªOFF.º
2. Disconnect SDM.
3. Disconnect SRS driver / passenger load tool.
4. Measure resistance on SDM harness connector from terminal
ª15º to terminal ª12º (IGNITION 1).
Does J±39200 display ª0Lº (infinite)?
Go to Step 5
Replace SRS
harness.
Go to
Step 6
5Measure resistance on SDM harness connector from terminal
ª16º to terminal ª12º (IGNITION 1).
Does J±39200 display ª0Lº (infinite)?
Go to Chart A .
Replace SRS
harness.
Go to
Step 6
61. Reconnect all components, ensure all component are properly
mounted.
2. Ignition switch ªON.º
Is passenger sense LO less than 3.5 volts?Ignition switch
ªOFF.ºReplace
SDM.Go to
Step
7
Go to Chart A .
71. Reconnect all components, ensure all component are properly
mounted.
2. Clear diagnostic trouble codes.
Was this step finished?
Repeat the ªSRS
Diagnostic
System Check.º
Go to Step 7

9J1±25
RESTRAINT CONTROL SYSTEM
DTC 21 Driver Deployment Loop Resistance High
D09R200001
Circuit Description:
When the ignition switch is turned ªONº, the SDM will
perform tests to diagnose critical malfunctions within
itself. Upon passing these tests, ªignition 1º, and
deployment loop voltages are measured to ensure they
are within their respective normal voltage ranges.
The SDM then proceeds with the ªResistance
Measurement Testº ªDriver Bag Lowº terminal ª4º is
grounded through a current sink and the driver current
source connected to ªDriver Bag Highº terminal ª3º allows
a known amount of current to flow. By monitoring the
voltage difference between ªDriver Bag Highº and ªDriver
Bag Lowº, the SDM calculates the combined resistance
of the driver air bag assembly, SRS coil assembly,
harness wiring CKTs IB05±YEL and IB06±YEL/BLK, and
connector terminal contact.
DTC Will Set When:
The combined resistance of the driver air bag assembly,
SRS Coil assembly, harness wiring CKTs IB05±YEL and
IB06±YEL/BLK, and connector terminal contact is above
a specified value. This test run once each ignition cycle
during the ªResistance Measurement Testº when:
No ªhigher priority faultsº are detected during
ªTurn±ONº
ªIgnition 1º voltage is in the specified value.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets
DTC 21.
DTC Will Clear When:
The ignition switch is turned ªOFFº.

RESTRAINT CONTROL SYSTEM 9J1±26
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 SDM.
3. This test verifies proper connection of the yellow
2±pin connector at the base of the steering column.
4. This test checks for proper contact and/or corrosion
of the 2±pin connector terminals at the base of
steering column.
5. This test isolate the malfunction to one side of the
SRS coil assembly yellow 2±pin 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 ª1º and ª2º of the SRS coil 2±pin
connector at the base of the steering column, terminal ª1º
and ª2º of the driver air bag assembly 2±pin connector at
the top of the steering column, SDM terminals ª3º and ª4º
or a poor wire to terminal connection in CKT IB05±YEL or
IB06±YEL/BLK. The test for this diagnostic trouble code
is only run while the ªAIR BAGº warning lamp is
performing the bulb check, unless DTC 17 or DTC 26 is
detected. When a scan tool ªClear Codesº command is
issued and the malfunction is still present, the DTC will not
reappear until the next ignition cycle.

9J1±27
RESTRAINT CONTROL SYSTEM
DTC 21 Driver Deployment Loop Resistance High
StepActionYe sNo
1Was the ªSRS Diagnostic System Checkº performed?
Go to Step 2
Go to the ªSRS
Diagnostic
System Check.º
21. When measurements are requested in this chart use J±39200
DVM with correct terminal adapter from J±35616±A.
2. Use scan tool data list function, read and record the driver
deployment loop resistance.
Is driver deployment loop resistance more than 4.4 ohms?
Go to Step 3 Go to Chart A .
31. Ignition switch ªOFF.º
2. Disconnect driver air bag assembly yellow 2±pin connector
located at base of steering column is seated properly.
Is the 2±pin connector connected properly?
Go to Step 4
Seat SRS coil
assembly 2±pin
connector
properly.Go to
Step 8
41. Disconnect and inspect the SRS coil assembly yellow 2±pin
connector located base of steering column.
2. If OK, reconnect the SRS coil assembly yellow 2±pin
connector.
3. Ignition switch ªON.º
Is DTC 21 current?
Go to Step 5
Ignition switch
ªOFF.º
Go to
Step 8
51. Ignition switch ªOFF.º
2. Disconnect SRS coil and passenger air bag assembly yellow
2±pin connectors located at the base of steering column and
behind the glove box assembly.
3. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter to SRS coil and passenger air bag
assembly harness connectors.
4. Ignition switch ªON.º
Is DTC 21 current?
Go to Step 6 Go to Step 7
61. Ignition switch ªOFF.º
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 CKTs IB05±YEL/IB06±GRN and YEL/BLK, and
SDM connector terminal ª3º and ª4º to locate the root cause.
Was a fault found?
Replace SRS
harness.
Go to
Step 8 Go to Chart A .
71. Ignition switch ªOFF.º
Disconnect SRS driver / passenger load tool from SRS coil
assembly harness connector.
Connect SRS driver / passenger load tool J±41433 on the top
of steering column.
Reconnect SRS coil assembly harness connector as the base
of steering column.
Ignition switch ªON.º
Is DTC 21 current?
Ignition switch
ªOFF.º
Replace SRS
COIL
ASSEMBLY.
Refer to in this
section 9J±24.
Go to
Step 8
Ignition switch
ªOFF.º
Replace driver air
bag assembly.
Go to
Step 8
8Reconnect all components, ensure all component are properly
mounted.
Clear diagnostic trouble codes.
Was this step finished?
Repeat the ªSRS
Diagnostic
System Check.º
Go to Step 8 .

RESTRAINT CONTROL SYSTEM 9J1±28
DTC 22 Driver Deployment Loop Resistance Low
D09R200001
Circuit Description:
When the ignition switch is turned ªONº, the SDM will
perform tests to diagnose critical malfunctions within
itself. Upon passing these tests ªignition 1º, and
deployment loop voltages are measured to ensure they
are within their respective normal voltage ranges.The
SDM then proceeds with the ªResistance Measurement
Testº ªDriver Bag Lowº terminal ª4º is grounded through a
current sink and the driver current source connected to
ªDriver Bag Highº terminal ª3º allows a known amount of
current to flow. By monitoring the voltage difference
between ªDriver Bag Highº and ªDriver Bag Lowº the SDM
calculates the combined resistance of the driver air bag
assembly, SRS coil assembly, harness wiring CKTs
IB05±YEL and IB06±YEL/BLK and connector terminal
contact.
DTC Will Set When:
The combined resistance of the driver air bag assembly,
SRS coil assembly, harness wiring CKTs IB05±YEL and
IB06±YEL/BLK and connector terminal contact is above a
specified value. This test is run once each ignition cycle
during the ªResistance Measurement Testº when:
1. No ªhigher priority faultsº are detected during
ªTurn±ONº
2. ªIgnition 1º voltage is in the specified value.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets
DTC 22.
DTC Will Clear When:
The ignition switch is turned ªOFF.º

9J1±29
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 malfunction is in
the SDM.
3. This test verifies proper connection of the yellow
2±pin connector at the base of the steering column.
4. This test checks for proper operation of the shorting
clip in the yellow 2±pin connector.
5. This test isolate the malfunction to one side of the
SRS coil assembly yellow 2±pin connector located
at the base of steering column.
6. This test determines whether the malfunction is due
to shorting 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 CKT IB05±YEL or IB06±YEL/BLK 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 ªAIR BAGº
warning lamp is performing the bulb check, unless DTC
17 or DTC 26 is detected. When a scan tool ªClear
Codesº command is issued and the malfunction is still
present, the DTC will not reappear until the next ignition
cycle.

RESTRAINT CONTROL SYSTEM 9J1±30
DTC 22 Driver Deployment Loop Resistance Low
StepActionYe sNo
1Was the ªSRS Diagnostic System Checkº performed?
Go to Step 2
Go to the ªSRS
Diagnostic
System Check.º
21. When measurements are requested in this chart use J±39200
DVM with correct terminal adapter from J±35616±A.
2. Use scan tool data list function, read and record the driver
deployment loop resistance.
Is driver resist. less than 1.9 ohms?
Go to Step 3 Go to Chart A .
31. Ignition switch ªOFF.º
2. Make sure the SRS coil assembly yellow 2±pin connector
located at the base of steering column is seated properly.
Is the 2±pin connector connected properly?
Go to Step 4
Seat driver air
bag assembly
2±pin connector
properly.
Go to
Step 8
41. Disconnect and inspect the SRS coil assembly yellow 2±pin
connector located base of steering column.
2. If OK, reconnect the driver air bag assembly yellow 2±pin
connector.
3. Ignition switch ªON.º
Is DTC 22 current?
Go to Step 5
Ignition switch
ªOFF.º
Go to
Step 8
51. Ignition switch ªOFF.º
2. Disconnect SRS coil and passenger air bag 2±pin connectors
located at the base of steering column and behind the glove
box assembly.
3. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter to SRS coil and passenger air bag
assembly harness connectors.
4. Ignition switch ªON.º
Is DTC 22 current?
Go to Step 6 Go to Step 7
61. Ignition switch ªOFF.º
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 CKTs IB05±YEL and IB06±YEL/BLK, and SDM
connector terminal ª3º and ª4º to locate the root cause.
Was a fault found?
Replace SRS
harness.
Go to
Step 8 Go to Chart A .
71. Ignition switch ªOFF.º
2. Disconnect SRS driver / passenger load tool from SRS coil
assembly harness connector.
3. Connect SRS driver / passenger load tool J±41433 to the top
of steering column.
4. Reconnect SRS coil assembly harness connector as the base
of steering column.
5. Ignition switch ªON.º
Is DTC 22 current?
Ignition switch
ªOFF.º
Replace SRS coil
assembly.
Refer to in this
section 9J±24.
Go to
Step 8
Ignition switch
ªOFF.º
Replace driver air
bag assembly.
Go to
Step 8
81. Reconnect all components, ensure all component are properly
mounted.
2. Clear diagnostic trouble codes.
Was this step finished?
Repeat the ªSRS
Diagnostic
System Check.º
Go to Step 8