Isuzu KB P190. Manual — part 1422

9A1-6 RESTRAINT CONTROL SYSTEM

Diagnostic Trouble Codes

Choose and trace an appropriate flowchart by the numbers listed below to find fault and repair.

DTC Flash

Code

Description

–

12

Diagnostic Display Mode (Flash Code only)

–

13

Diagnostic Display Mode (Flash Code only)

B0015

15

Passenger Air Bag Squib Circuit High Resistance

B0016

16

Passenger Air Bag Squib Circuit Low Resistance

B0018

18

Passenger Air Bag Squib Circuit Short to GND

B0019

19

Passenger Air Bag Squib Circuit Short to Battery Voltage

B0021

21

Driver Air Bag Squib Circuit High Resistance

B0022

22

Driver Air Bag Squib Circuit Low Resistance

B0025

25

Driver Air Bag Squib Circuit Short to GND

B0026

26

Driver Air Bag Squib Circuit Short to Battery Voltage

B0029

29

Passenger Pretensioner Squib Circuit High Resistance

B0031

31

Passenger Pretensioner Squib Circuit Low Resistance

B0033

33

Passenger Pretensioner Squib Circuit Short to GND

B0034

34

Passenger Pretensioner Squib Circuit Short to Battery Voltage

B0041

41

Driver Pretensioner Squib Circuit High Resistance

B0042

42

Driver Pretensioner Squib Circuit Low Resistance

B0045

45

Driver Pretensioner Squib Circuit Short to GND

B0046

46

Driver Pretensioner Squib Circuit Short to Battery Voltage

B0051

51

Air Bag Squib Circuit Activated (Clash)

B0052

52

Pretensioner Squib Circuit Activated

B0055

55

Vehicle Variant Missing

B0061

61

Warning Lamp Circuit Failure

B0062

62

Battery Voltage Too High

B0063

63

Battery Voltage Too Low

B0071

71

SRS Control Unit Internal Fault

RESTRAINT CONTROL SYSTEM 9A1-7

System Schematic

RTW79ALF000301

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 “SRS”
warning lamp operation, the ability of the SRS
control unit 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
preformed.

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.

9A1-8 RESTRAINT CONTROL SYSTEM

Circuit Description

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

Notes On System Check Chart

1. The “SRS” warning lamp should flash seven times

after the ignition is first turned “ON”.

2. After the “SRS” warning lamp flashes seven times, it

should turn to “LOCK”

3. 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.

4. Improper operation of the “SRS” warning lamp is

indicated. This test differentiates between ‘a
warning lamp stays “ON” condition’ and ‘a warning
lamp does not come “ON” condition’.

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.

SRS Diagnostic System Check

Step Action

Yes

No

1

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

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

Go to Step 2

Go to Step 3

2

Note the “SRS” warning lamp after it flashed 7 times.

Does the “SRS” warning lamp go “OFF”?

Go to Step 4

Go to Step 5

3

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

Does the “SRS” warning lamp come “ON” steady?

Go to Chart B.

Go to Chart C.

4

1. Note the “SRS” warning lamp as the ignition switch is turned

“ON”.

Ignition switch is at “LOCK”.

2. Connect a scan tool to data link connector.

3. Follow direction given in the scan tool instruction manual.

Ignition switch is “ON”.

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

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

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

Ignition switch

“LOCK”.

When DTC B0071

is set, go to DTC

B0071 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

malfunctions, no

further diagnosis is

required.

If scan tool

indicated “NO

DATA

RECEIVED,” refer

to chassis

electrical section 8.

RESTRAINT CONTROL SYSTEM 9A1-9

Step Action

Yes

No

5

1. Ignition switch is at “LOCK”.

2. Connect a scan tool to data link connector.

3. Follow directions as given in the scan tool instruction manual.

4. Ignition switch is “ON”.

5. Request the SRS diagnostic trouble code display, Recode all

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

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

Ignition switch

“LOCK”.

When the current

DTC is set, go to

applicable DTC

chart.

And then if DTC

B0019, B0025,

B0051, B0055 or

B0071 is set, go to

these DTC chart

first.

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 8.