Isuzu Trooper (1998-2002 year). Manual - part 1092

9J1–5

RESTRAINT CONTROL SYSTEM

diagnostic trouble codes in the order specified may result

in  extended  diagnostic  time,  incorrect  diagnosis  and
incorrect parts replacement.

SRS Diagnostic System Check 

Step

Action

Yes

No

1

Note the “Air Bag” warning lamp as ignition switch is turned “ON.”

Does the “AIR BAG” warning lamp turn on 3.5 seconds?

Go to Step 2

Go to Step 3

2

Note the “AIR BAG” warning lamp after it turn on 3.5 seconds.

Does the “AIR BAG” warning lamp go “OFF”?

Go to Step 4

Go to Step 5

3

Note the “AIR BAG” warning lamp as ignition switch is turned
“ON”.

Does the “AIR BAG” warning lamp come “ON” steady?

Go to Chart B

Go to Chart C

4

1. Note the “AIR BAG” warning lamp as that ignition switch is

turned “ON.”
Ignition switch “OFF.”

2. Connect a scan tool to data link connector. 
3. Follow direction given in the scan tool instruction manual.

Ignition switch “ON.”

4. Request the SRS diagnostic trouble code display, recode all

history diagnostic trouble code(s). specify as such, on repair
order

Is (are) diagnostic trouble code(s) displayed?

Ignition switch

“OFF”

When DTC 71 is

set, go to DTC 71

Chart

For all other

history codes

refer to

“Diagnostic Aids”

For that specific

DTC 

A history DTC

indicates the

malfunction has

been repaired or

is intermittent

SRS is functional

and free of

malfuncitons, no

further diagnosis

is required 

If scan tool

indicated “NO

DATA

RECEIVED,”

refer to chassis

electrical section8

5

1. Ignition switch “OFF.”
2. Connect a scan tool to data link connector.
3. Follow directions as given in the scan tool instruction manual.
4. Ignition switch “ON.”
5. Request the SRS diagnostic trouble code display, Recode all

diagnostic trouble code(s), specifying as current or history on
repair order.

Is (are) diagnostic trouble code (s) displayed?

Ignition switch

“OFF”

When DTC 53 is

set, go to DTC 53

chart

When DTC 51 is

set, go to DTC 51

chart

When DTC 19  is

set, go to DTC 19

chart

When DTC 25  is

set, go to DTC 25

chart

Diagnose

remaining current

DTCs from

lowest to highest

When only history

DTCs exist, refer

to “Diagnostics

Aids” for that
specific DTC

A history DTC

indicates the

malfunction has

been repaired or

is intermittent

If scan tool

indicates “No

Data Received,”

refer to chassis

electrical section8

RESTRAINT CONTROL SYSTEM

9J1–6

Chart A  SDM Integrity Check

D09RW014

Circuit Description:

When the SDM recognizes “Ignition 1” voltage, applied to
terminals “12”, is greater than 9 volts, the “AIR BAG”
warning lamp is turned on 3.5 seconds to verify operation.
At this time the SDM performs “Turn–ON” tests followed
by “Continuous Monitoring” tests.  When a malfunction is
detected, the SDM sets a current diagnostic trouble code
and illuminates the “AIR BAG” warning lamp. The SDM
will clear current diagnostic trouble codes and move them
to a history file when the malfunction is no longer detected
and/or the ignition switch is cycled, except for DTCs 19,
25, 51, 53 and 71.  DTC 71 can only be cleared using a
scan tool “Clear Codes” command.  If DTCs 51, 53 are not
indicated then DTC 71 is not existing. DTCs 51, 53 and 71
can not be cleared after a “Clear Codes” command is
issued.

Chart Test Description: 

Number(s) below refer to step number(s) on the
diagnostic chart:
1. This test confirms a current malfunction.  If no

current malfunction is occurring (history DTC set)
the “Diagnostic Aids” for the appropriate diagnostic
trouble code should be referenced.  The SDM
should not be replaced for a history diagnostic
trouble code.

2. This test checks for a malfunction introduced into the

SRS during the diagnostic process.  It is extremely
unlikely that a malfunctioning SDM would cause a
new malfunction to occur during the diagnostic
process.

3. When all circuitry outside the SDM has been found

to operate properly, as indicated by the appropriate
diagnostic chart, then and only then should the SDM
be replaced.

9J1–7

RESTRAINT CONTROL SYSTEM

Chart A  SDM Integrity Check 

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

Action

Yes

No

1

1. This chart assumes that the “SRS Diagnostic System Check”

and either a symptom chart or a diagnostic trouble code chart
diagnosis have been performed.  When all circuitry outside the
SDM has been found to operate properly, as indicated by the
appropriate diagnostic chart, and the symptom or DTC
remains current, the following 

2. Diagnostic procedures must be performed to verify the need

for SDM replacement. 

3. Ignition switch “OFF”.
4. Reconnect all SRS components, ensure all components are

properly mounted.   

5. Ensure the ignition switch has been “OFF” for at least 15

seconds.

6. Note “AIR BAG” warning lamp as ignition switch is turned

“ON.”

Does warning lamp turn on 3.5 seconds then go “OFF”?

The symptom or

DTC is no longer

occurring

Clear SRS

diagnostic trouble

codes  

Repeat “SRS

Diagnostic

System Check”

Go to Step 2

2

Using a scan tool request diagnostic trouble code display

Is the same symptom or DTC occurring as was when the “SRS
Diagnostic System Check ” was first performed?

Go to Step 3

Ignition switch

“OFF”  

Go to the

appropriate chart

for the indicated

malfunction

3

1. Clear “SRS Diagnostic Trouble Codes”.
2. Ignition switch “OFF” for at least two minutes.
3. Note “AIR BAG” warning lamp as ignition switch is turned

“ON.”

Does warning lamp turn on 3.5 seconds then go “OFF”?

SRS is functional

and free of

malfunctions

No further

diagnosis is

required

Go to Step 4

Ignition switch

“OFF”

Replace SDM

Go to Step 4

4

Reconnect all SRS components, ensure all components are
properly mounted.

Was this step finished?

Repeat the “SRS

Diagnostic

System Check”

Go to Step 4

RESTRAINT CONTROL SYSTEM

9J1–8

Chart B  “AIR BAG” Warning Lamp Comes “ON” Steady

D09RW014

Circuit Description:

When the ignition switch is first turned “ON”, “Ignition 1”
voltage is applied from the “C–10” fuse to “AIR BAG”,
warning lamp which is connected to “SRS Warning
Lamp”, terminal “7”.  The “C–21” fuses apply system
voltage to the “Ignition 1” inputs, terminals “12”.  The SDM
responds by turning on the “AIR BAG” warning lamp 3.5
seconds.  If “Ignition 1” is less than 9 volts, the “AIR BAG”
warning lamp will come “ON” solid with no DTCs set.

Chart Test Description: 

Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for an open in the “Ignition 1” circuit

to the SDM.

3. This test checks for the voltage of “IGNITION 1”.
4. This test determines whether the malfunction is a

short to ground in IB04–WHT/RED.