Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 514

9J1–3

RESTRAINT CONTROL SYSTEM

“Flash Code” Diagnostics

Flash code diagnostics can be used to read current codes
and to determine if history codes are present but cannot
be used to clear codes or read history codes. Flash code
diagnostics is enabled by grounding by terminal 13
shorting to terminal 4 of the DLC with the ignition switch
“ON”. Grounding terminal 13 of the DLC pulls the
“Diagnostics Request” input (Terminal 1) of the SDM low
and signals the SDM to enter the flash code diagnostic
display mode.
The SDM displays the trouble codes by flashing the
warning lamp. Each code that is displayed will consist of a
number of flashes which represents the tens digit, a 1.2
second pause, following by a number of flashes which
represents the ones digit of the code. Each code is

displayed one time before moving on to the next code.
After all of the codes have been displayed, the entire code
sequence will continually by repeated until ground is
removed from terminal 13 of the DLC.
Two special codes exist when reading in the flash code
mode (Flash Code 12 and Flash Code 13).  “Flash Code
12” will always be the first code displayed when the flash
code mode is enabled Code 12 is not an indication of a
SRS problem but an indication that the flash code mode
has been enabled.  If there are no current or history codes
present, the SDM will display code 12 until ground is
removed from the DLC at terminal 13.  “Flash Code 13”
will be displayed if there are history codes.  To read the
history codes, a scan tool must be used.

System Schematic

D09R200001

RESTRAINT CONTROL SYSTEM

9J1–4

SRS Diagnostic System Check

The diagnostic procedures used in this section are
designed to find and repair SRS malfunctions.  To get the
best results, it is important to use the diagnostic charts
and follow the sequence listed below:
A. Perform the “SRS Diagnostic System Check.”

The “SRS Diagnostic System Check” must be the
starting point of any SRS diagnostics.  The “SRS
Diagnostic System Check” checks for proper “AIR
BAG” warning lamp operation, the ability of the SDM
to communicate through the “Serial Data” line and
whether SRS diagnostic trouble codes exist.

B. Refer to the proper diagnostic chart as directed by the

“SRS Diagnostic System Check.”
The “SRS Diagnostic System Check” will lead you to
the correct chart to diagnose any SRS malfunctions.
Bypassing these procedures may result in extended
diagnostic time, incorrect diagnosis and incorrect
parts replacement.

C. Repeat the “SRS Diagnostic System Check” after any

repair or diagnostic procedures have been
performed.
Performing the “SRS Diagnostic System Check” after
all repair or diagnostic procedures will ensure that the
repair has been made correctly and that no other
malfunctions exist

Circuit Description

When the ignition switch is first turned “ON”, “ignition 1”
voltage is applied from the “SRS–1” fuse to the SDM at
the “ignition 1” input terminals “12”.  The SDM responds
by flashing the “AIR BAG” warning lamp seven times
while performing tests on the SRS.

Notes On System Check Chart:

Number(s) below refer to step number(s) on the “SRS
Diagnostic System Check” chart.
1. The “AIR BAG” warning lamp should flash seven

times after ignition is first turned “ON.”

2. After the “AIR BAG” warning lamp flashes seven

times, it should turn “OFF.”

3. Improper operation of the “AIR BAG” warning lamp

is indicated.  This test differentiates a warning lamp
stays “ON” condition from a warning lamp does not
come “ON” condition. 

4. This test checks for the proper operation of the

“Serial Data” line.  This test will also determine
whether history diagnostic trouble codes are stored
and, if so, identify them.

5. This test checks for proper operation of the “Serial

Data” line.  This test will also identify the stored
diagnostic trouble codes and whether they are
current or history.

Diagnostic Aids:

The order in which diagnostic trouble codes are
diagnosed is very important.  Failure to diagnose the
diagnostic trouble codes in the order specified may result
in extended diagnostic time, incorrect diagnosis and
incorrect parts Replacement.

9J1–5

RESTRAINT CONTROL SYSTEM

SRS Diagnostic System Check 

Step

Action

Yes

No

1

Confirm the “AIR BAG” warning lamp when ignition switch is
turned “ON.”

Does the “AIR BAG” warning lamp flash seven (7) times?

Go to 

Step 2  

Go to 

Step 3 

2

Confirm the “AIR BAG” warning lamp after it flashed 7 times.

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

Go to 

Step 4 

Go to 

Step 5 

3

Confirm the “AIR BAG” warning lamp when ignition switch is
turned “ON.”

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

Go to 

Chart B.

Go to 

Chart C.

4

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

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

Is 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

“Diagnostics

Aids” for that

specific DTC.

A history DTC

indicates the

malfunction has

been repaired or

is intermittent.

SRS is functional

and free of

malfunctions, no

further diagnosis

is required.

If scan tool

indicates “No

Data Received,”

refer to chassis

electrical section.

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 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 section.

RESTRAINT CONTROL SYSTEM

9J1–6

Chart A  SDM Integrity Check

D09R200001

Circuit Description:

When the SDM recognizes “ignition 1” voltage, applied to
terminals “12”, is greater than 9 volts, the “AIR BAG”
warning lamp is flashed 7 times 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 51,
53 and 71.  DTC 71 can only be cleared using a scan tool
“Clear Codes” command in case that the malfunction on
DTC 71 has been solved and no DTCs 51 and 53 were
remained.  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 Confirm s 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.