Isuzu N-Series. Manual - part 1199

SRS CONTROL SYSTEM 9C-43

Step

Action

Value

YES

NO

1

Has the “SRS system check” been per-
formed? 

—

Go to Step2

Go to “SRS sys-

tem check”.

2

1. When measurement is required in this

chart, use 5-8840-0366-0 DMM and ap-
propriate terminal adapter in 5-8840-
0385-0 Connector test adapter kit.

2. Turn the starter switch to OFF.
3. Check the 2-pole connector (yellow) of

SRS coil assembly located in the lower
portion of steering column for proper con-
nection.

Is the 2-pole connector (yellow) connected
properly?

—

Go to Step3

Connect the 2-

pole connector of 

SRS coil assem-

bly properly.Go to 

Step6

3

1. Remove the 2-pole connector (yellow) of

SRS coil assembly located in the lower
portion of steering column for inspection.

2. If it is normal, reconnect the 2-pole con-

nector of SRS coil assembly properly.

3. Turn the starter switch to ON.

Is DTC 26 detected as current trouble?

—

Go to Step4

Go to Step7

4

1. Turn the starter switch to OFF.
2. Remove the 2-pole connector (yellow) of

SRS coil assembly located in the lower
portion of steering column.

3. Connect the 5-8840-2421-0 SRS substi-

tute load and an appropriate terminal
adapter in 5-8840-0385-0 Connector test
adapter kit to the SRS harness side con-
nector which connects to SRS coil as-
sembly.

4. Turn the starter switch to ON.

Is DTC 26 detected as current trouble?

—

Go to Step5

Go to Step6

5

1. Turn the starter switch to OFF.
2. Driver’s airbag deployment circuit is

open.

3. Inspect the SRS airbag deployment cir-

cuit and SRS control unit connector ter-
minals “7” and “8”, and use high-
resolution resistance meter mode of
DMM to detect the cause.

Is the trouble detected?

—

Replace the SRS 

harness.Go to 

Step7

Go to Chart A 

SRS control unit 

function check.

9C-44 SRS CONTROL SYSTEM

6

1. Turn the starter switch to OFF.
2. Remove the 5-8840-2421-0 SRS substi-

tute load from SRS coil assembly har-
ness connector.

3. Connect the 5-8840-2421-0 SRS substi-

tute load to the upper portion of steering
column.

4. Reconnect the SRS coil assembly har-

ness connector to the lower portion of
steering column.

5. Turn the starter switch to ON.

Is DTC 26 detected as current trouble?

—

Turn the starter 

switch to OFF. 

Replace the SRS 

coil assembly by 

referring to “SRS 

Coil Assembly” in 

SRS section. Go 

to Step7

Turn the starter 

switch to OFF. 

Replace the SRS 

airbag. Go to 

Step7

7

1. Reconnect all the parts, and check that

those are installed properly.

2. Clear the DTC.

Is this step completed?

—

Repeat the “SRS 

system check”.

Go to Step7

Step

Action

Value

YES

NO

SRS CONTROL SYSTEM 9C-45

DTC: 51  SRS Airbag Deployment Current Had Output

Outline

Description of Circuit
A sensor is equipped to this circuit to convert the impact
applied to SRS control unit into an electrical signal.
The electrical signal generated at this time will be pro-
cessed in the SRS control unit to compare with the value
stored in the memory. When the generated signal ex-
ceeds the setting value, SRS control unit sends current
to the SRS airbag assembly for deployment, and set the
DTC 51.

Condition when DTC is Set
When the control unit detects the front collision over cer-
tain degree of impact.

Action to be Taken
SRS control unit turns the “SRS” warning lamp ON,
record the “collision data”, and set the DTC 51.

Condition when DTC is Cleared
When SRS control unit is replaced. 

Description of DTC Chart Test
Numbers below indicate step numbers in the diagnostic
chart.
2. In case the DTC 51 appears even when the collision
did not result in SRS airbag assembly deployment, the
DTC 51 may have been set erroneously.
3. In case the DTC 51 appears without any deformation
caused by front collision, the DTC may have been set
erroneously.

WARNING:

DURING SERVICE WORK, BE CAREFUL NOT TO
TAP OR SHAKE THE SRS CONTROL UNIT. ALSO,
FAILURE TO INSTALL THE SRS CONTROL UNIT TO
VEHICLE PROPERLY MAY LEAD TO MALFUNC-
TION OF THE UNIT WHEN THE STARTER SWITCH IS
TURNED TO ON. THIS MAY RESULT IN INJURY DUE
TO SUDDEN DEPLOYMENT OF SRS AIRBAG.

SRS CONTROL UNIT

AIRBAG

SRS COIL

ASSEMBLY

1

2

2

1

0.5

Y

0.5

Y/B

8

7

N9A0076E

Step

Action

Value

YES

NO

1

Has the “SRS system check” been per-
formed? 

—

Go to Step2

Go to “SRS sys-

tem check”.

9C-46 SRS CONTROL SYSTEM

2

Turn the starter switch to OFF.

Is the airbag assembly deployed?

—

Inspect according 

to “repair and 

inspection 

required after col-

lision” in this sec-

tion. Clear the 

DTC. Perform 

“SRS system 

check”.

Go to Step3

3

Check front area of the vehicle for deforma-
tion caused by front collision.

Is any deformation found?

—

Replace the parts, 

and inspect 

according to 

“repair and 

inspection 

required after col-

lision” in this sec-

tion. Clear the 

DTC. Perform 

“SRS system 

check”.

Turn the starter 

switch to OFF. 

Replace the SRS 

control unit. 

Reconnect all the 

SRS system 

parts, and check 

that those are 

installed properly. 

Perform “SRS 

system check”.

Step

Action

Value

YES

NO