ISUZU AXIOM 2002 Service Repair Manual

9J1±31
RESTRAINT CONTROL SYSTEM
DTC 24 Driver Deployment Loop Short To Ground
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 voltage at ªDriver Bag Lowº
terminal ª4º and ªPassenger Bag Lowº terminal ª16º to
detect shorts to ground in the air bag assembly circuits.
DTC Will Set When:
Neither of the two air bag assemblies is open.
ªIgnition 1º is within the normal operating voltage range.
This test is run once each ignition cycle and ªContinuous
Monitoringº. Once these conditions are met and the
voltage at ªDriver Bag Lowº is below a specified value,
DTC 24 will set.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets a
diagnostic trouble code.
DTC Will Clear When:
The malfunction is no longer occurring and the ignition is
turned ªOFF.º
DTC Chart Test Description:
Number(s) below refer to step number(s) on the
diagnostic chart:
2. This test determines whether the SDM 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
CKT IB05±YEL.

RESTRAINT CONTROL SYSTEM 9J1±32
5. This test determines whether the malfunction is in
CKT IB06±YEL/BLK.
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 in the driver air bag assembly circuit. Inspect
CKTs IB05±YEL and IB06±YEL/BLK carefully for cutting
or chafing.
DTC 24 Driver Deployment Loop Short To Ground
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. Ignition switch ªOFF.º
3. Connect scan tool data link connector. Follow directions as
given in the scan tool operator's manual.
Ignition switch ªON.º
4. Read driver sense LO.
Is driver sense LO less than 1.5 volts?
Go to Step 3 Go to Chart A .
31. Ignition switch ªOFF.º
2. Disconnect SRS coil assembly yellow 2±pin connector located
at base of the steering column. Leave passenger air bag
assembly connected.
3. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter to SRS coil assembly harness connector.
4. Ignition switch ªON.º
Is DTC 24 current?
Go to Step 4 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 ª3º to terminal
ª6º (ground).
Does J±39200 display ª0Lº (infinite)?
Go to Step 5
Replace SRS
harness.
Go to
Step 7
5Measure resistance on SDM harness connector from terminal ª4º
to terminal ª6º (ground).
Does J±39200 display ª0Lº (infinite)?
Go to Chart A .
Replace SRS
harness.
Go to
Step 7
61. Ignition switch ªOFF.º
2. Disconnect SRS driver / passenger load tool J±41433 from
SRS coil assembly harness connector.
3. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter J±35616±A to driver air bag assembly
harness connector. Located top of the steering column.
4. Reconnect SRS coil assembly harness connector as the base
of steering column.
5. Ignition switch ªON.º
Is DTC 24 current?
Ignition switch
ªOFF.º
Replace SRS coil
assembly.
Refer to in this
section 9J±24.
Go to
Step 7
Ignition switch
ªOFF.º
Replace driver air
bag assembly.
Go to
Step 7
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±33
RESTRAINT CONTROL SYSTEM
DTC 25 Driver 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 voltage at ªDriver Bag Lowº
terminal ª4º and ªPassenger Bag Lowº terminal ª16º to
detect shorts to B+ in the air bag assembly circuits.
DTC Will Set When:
ªIgnition 1º is in the normal operating voltage range. This
test is run once each ignition cycle and ªContinuous
Monitoringº. Once these conditions are met and the
voltage at ªDriver Bag Lowº is above a specified value,
DTC 25 will set.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets
DTC 25 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 SDM is
malfunctioning.
3. This test isolates the malfunction to one side of the
SRS coil assembly yellow 2±pin connector at the
base of steering column.
4. This test determines whether the malfunction is in
CKT IB05±YEL.
5. This test determines whether the malfunction is in
CKT IB06±YEL/BLK.

RESTRAINT CONTROL SYSTEM 9J1±34
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 B+ in the driver air bag assembly circuit. Inspect CKTs
IB05±YEL and IB06±YEL/BLK carefully for cutting or
chafing. If the wiring pigtail of the driver air bag assembly
and SRS coil assembly is damaged, the components
must be replaced. A careful inspection of CKT IB05±YEL
and IB06±YEL/BLK, including the SRS coil assembly and
driver air bag assembly is essential to ensure that the
replacement SDM will not be damaged.

9J1±35
RESTRAINT CONTROL SYSTEM
DTC 25 Driver Deployment Loop Short To Ignition
CAUTION: When DTC 25 has been set, it is necessary to replace the SDM. Setting DTC 25 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 driver sense LO.
Is driver sense LO more than 3.5 volts?
Go to Step 3 Go to Chart A .
31. Ignition switch ªOFF.º
2. Disconnect SRS coil assembly yellow 2±pin connector at the
base of the steering column. Leave passenger air bag
assembly connected.
Connect SRS driver / passenger load tool J±41433 and
appropriate adapter to SRS coil assembly harness connector.
3. Ignition switch ªON.º
Is driver sense LO more than 3.5 volts?
Go to Step 4 Go to Step 6
41. Ignition switch ªOFF.º
2. Disconnect SDM.
3. Disconnect SRS drive / passenger load tool.
4. Measure resistance on SDM harness connector from terminal
ª3º to terminal ª12º (Ignition 1).
Does J±39200 display ª0Lº (infinite)?
Go to Step 5
Replace SRS
harness.
Go to
Step 7
5Measure resistance on SDM harness connector from terminal ª4º
to terminal ª12º (Ignition 1).
Does J±39200 display ª0Lº (infinite)?
Go to Chart A .
Replace SRS
harness.
Go to
Step 7
61. Ignition switch ªOFF.º
2. Connect SRS driver / passenger load tool J±41433 and
appropriate adapter J±35616±A to driver air bag assembly
harness connector located of top of the steering column.
3. Reconnect SRS coil assembly harness connector as the base
of steering column.
4. Ignition switch ªON.º
Is driver sense LO more than 3.5 volts?
Ignition switch
ªOFF.º
Replace SRS coil
assembly.
Go to
Step 7
Ignition switch
ªOFF.º
Replace driver air
bag assembly.
Go to
Step 7
71. Reconnect all components, ensure all components are
properly mounted.
2. Ignition switch ªON.º
Is passenger sense LO less than 3.5 volts?
Replace SDM.
Go to
Step 8 Go to Chart A .
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble codes.
Was this step finished?
Repeat the ªSRS
Diagnostic
System Check.º
Go to Step 8

RESTRAINT CONTROL SYSTEM 9J1±36
DTC 26 Driver Deployment Loop Open
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.
During ªContinuous Monitoringº diagnostics, a fixed
amount of current is following in the deployment loop.
This produces proportional voltage drops in the loop. 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 voltage difference between ªDriver Bag Highº
terminal ª3º and ªDriver Bag Lowº terminal ª4º is above orequal to a specified value for 500 milliseconds during
ªContinuous Monitoring.º
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp and sets a
diagnostic trouble code.
DTC Will Clear When:
The voltage difference between ªDriver Bag Highº
terminal ª3º and ªDriver Bag Lowº terminal ª4º is below a
specified value for 500 milliseconds during ªContinuous
Monitoring.º
DTC Chart Test Description:
Number(s) below refer to circled number(s) on the
diagnostic chart:
1. This test determines whether the malfunction is in
the SDM.

9J1±37
RESTRAINT CONTROL SYSTEM
2. This test verifies proper connection of the yellow
2±pin connector at the base of the steering column.
3. This test checks for proper contact and/or corrosion
of the yellow 2±pin connector at the base of the
steering column.
4. This test isolates the malfunction to one side of the
SRS coil assembly yellow 2±pin connector located
at the base of steering column.
5. This test determines whether the open is in the
wiring.
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 poor
connection at the driver air bag assembly harness 2±pin
connector terminals ª1º and ª2º at the top of the steering
column, SRS coil assembly harness 2±pin connection
terminals ª1º and ª2º, SDM terminals ª3º and ª4º, or an
open in CKTs IB05±YEL and IB06±YEL/BLK.

RESTRAINT CONTROL SYSTEM 9J1±38
DTC 26 Driver Deployment Loop Open
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
differential voltage.
Is driver differential voltage more than 4.0 volts?
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 yellow 2±pin connector connected properly?
Go to Step 4
Seat driver air
bag assembly
2±pin connector.
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 ªONº.
Is DTC 26 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 26 current?
Go to Step 6 Go to Step 7
61. Ignition switch ªOFF.º
2. There has been an open circuit in the driver deployment loop.
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 on steering
column.
4. Reconnect SRS coil assembly harness connector as the base
of steering column.
5. Ignition switch ªON.º
Is DTC 26 current?
Ignition switch
ªOFF.º
Replace SRS coil
assembly, refer to
in this section
9J±3.
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

9J1±39
RESTRAINT CONTROL SYSTEM
DTC 51 Deployment Event Commanded
D09R200001
Circuit Description:
The SDM contains a sensing device which converts
vehicle velocity changes to an electrical signal. The
electrical signal generated is processed by the SDM and
then compared to a value stored in memory. When the
generated signal exceeds the stored value, the SDM will
cause current to flow through the air bag assembly
deploying the air bags and causing DTC 51 to set.
DTC Will Set When:
The SDM detects a frontal crash, up to 30 degrees off the
centerline of the vehicle, of sufficient force to warrant
deployment of the air bags.
Action Taken:
SDM turns ªONº the ªAIR BAGº warning lamp records
ªCrash Dataº, and sets a diagnostic trouble code.
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. If air bag assembly (s) has not deployed, DTC 51
may have falsely set.
3. If DTC 51 has set with no signs of frontal impact, the
diagnostic trouble code has falsely set.

RESTRAINT CONTROL SYSTEM 9J1±40
DTC 51 Deployment Event Commanded
WARNING:DURING SERVICE PROCEDURES. BE VERY CAREFUL WHEN HANDLING A SENSING AND
DIAGNOSTIC MODULE (SDM). NEVER STRIKE OR JAR THE SDM. NEVER POWER UP THE SRS WHEN THE
SDM IS NOT RIGIDLY ATTACHED TO THE VEHICLE. ALL SDM AND MOUNTING BRACKET FASTENERS MUST
BE CAREFULLY TORQUED AND THE ARROW MUST BE POINTING TOWARD THE FRONT OF THE VEHICLE
TO ENSURE PROPER OPERATION OF THE SRS. THE SDM COULD BE ACTIVATED WHEN POWERED WHILE
NOT RIGIDLY ATTACHED TO THE VEHICLE WHICH COULD CAUSE DEPLOYMENT AND RESULT IN
PERSONAL INJURY.
Step
ActionYe sNo
1Was the ªSRS Diagnostic System Checkº performed?
Go to Step 2
Go to the ªSRS
Diagnostic
System Check.º
2Ignition switch ªOFF.º
Have air bag assemblies deployed?Replace
components and
perform
inspections as
directed in
ªrepairs and
inspections
required after an
accidentº in this
section.
Clear diagnostic
trouble codes.
Repeat the ªSRS
Diagnostic
System Check.º
Go to Step 3
3Inspect front of vehicle and undercarriage for signs of impact.
Were signs of impact found?Replace
components and
perform
inspections as
directed in
ªrepairs and
inspections
required after an
accidentº in this
section.
Clear diagnostic
trouble codes.
Repeat the ªSRS
Diagnostic
System Check.º
Ignition switch
ªOFF.º
Replace SDM.
Reconnect all
SRS system
components,
ensure all
components are
properly
mounted.Repeat
the ªSRS
Diagnostic
System Check.º