Isuzu KB P190. Manual — part 1426

9A1-22 RESTRAINT CONTROL SYSTEM

Step Action

Yes

No

6

1. Ignition switch is at “LOCK”.

2. There has been a decrease in the total circuit resistance of

the passenger inflator deployment loop.

3. Use the high resolution ohmmeter mode of the DMM while

checking the circuits “Passenger Bag High” and “Passenger
Bag Low”, and the SRS control unit connector terminal “17”
and “16” to locate the root cause.

Was a fault found?

Replace SRS

harness.

Go to Step 7

Go to Chart A

7

1. Reconnect all components and ensure all components are

properly mounted.

2. Clear the diagnostic trouble codes.
Is this step finished?

Repeat the “SRS

Diagnostic System

Check”

―

RESTRAINT CONTROL SYSTEM 9A1-23

DTC B0018 (Flash Code 18) Passenger Air Bag Squib Circuit Short to GND

RTW79ALF000301

Circuit Description

When the ignition switch is turned “ON”, the SRS
control unit will perform tests to diagnose critical
malfunctions within itself. Upon passing these tests,
“Ignition 1”, and the deployment loop voltages are
measured to ensure they are within their respective
normal voltage ranges.
The SRS control unit monitors the voltages at the
“Driver Bag Low” terminal “13” and “Passenger Bag
Low” terminal “16” to detect short to ground/+B in the air
bag assembly circuits.

DTC Will Set When

“Ignition 1" is within the normal operating voltage range.
The voltage at “Passenger Bag Low" is below a
specified value DTC B0018 will set.

Action Taken

The SRS control unit turns “ON” the “SRS” warning
lamp and sets a diagnostic trouble code.

9A1-24 RESTRAINT CONTROL SYSTEM

DTC Will Clear When

The “Passenger Bag Low" voltage comes to specified
voltage.

DTC Chart Test Description

Number(s) below refer to circled number(s) on the
diagnostic chart.
2. This test determines whether the SRS control unit is

malfunctioning.

3. This test isolates the malfunction to one side of the

passenger air bag assembly yellow connector
behind the glove box compartment.

4. This test determines whether the malfunction is in

the “Passenger Bag High” circuit.

5. This test determines whether the malfunction is in

the “Passenger Bag Low” circuit.

Diagnostic Aids

An intermittent condition is likely to be caused by a short
to ground/+B in the passenger air bag assembly circuit.
Inspect circuits “Passenger Bag High” and “Passenger
Bag Low” carefully for cutting or chafing. If the wiring
pigtail of the passenger air bag assembly is damaged,
the component must be replaced.

DTC B0018 (Flash Code 18) Passenger Air Bag Squib Circuit Short to GND

Step Action

Yes

No

1

Was the “SRS Diagnostic System Check” performed?

Go to Step 2

Go to the “SRS

Diagnostic System

Check”

2

1. When measurements are requested in this chart use a 5-

8840-0366-0 DMM with a correct terminal adapter from 5-
8840-2835-0.

2. Ignition switch is at “LOCK”.

3. Ignition switch is “ON”.

4. Check the passenger air bag squib circuit for a short to

ground.

Was a problem found?

Go to Step 3



3

1. Ignition switch is at “LOCK”.

2. Disconnect the passenger air bag assembly yellow connector

behind the glove box assembly.

3. Leave the driver air bag assembly connected.

4. Connect the SRS driver / passenger load tool 5-8840-2421-0

and appropriate adapter to the passenger air bag assembly
harness connector.

5. Ignition switch is “ON”.
Is DTC B0018 current?

Go to Step 4

Ignition switch is at

“LOCK”.
Replace

passenger air bag

assembly .

Go to Step 6

4

1. Ignition switch is at “LOCK”.

2. Disconnect the SRS driver /passenger load tool.

3. Measure the resistance on the SRS control unit harness

connector as follow.

From terminals "17" to "3" and "23" (ground) (without the

pretensioner)

From terminals "17" to "3" and "15" (ground) (with the

pretensioner)

Does 5-8840-0366-0 display “OL” (Infinite)?

Go to Step 5

Replace SRS

Harness.

Go to Step 6

RESTRAINT CONTROL SYSTEM 9A1-25

Step Action

Yes

No

5

Measure the resistance on the SRS control unit harness
connector as follow.

From terminals "16" to "3" and "23" (ground) (without the

pretensioner)

From terminals "16" to "3" and "15" (ground) (with the

pretensioner)

Does 5-8840-0366-0 display “OL” (Infinite)?

Go to Chart A

Replace SRS

Harness.

Go to Step 6

6

1. Reconnect all the components and ensure all components

are properly mounted.

2. Clear diagnostic trouble codes.
Is this step finished?

Go to the “SRS

Diagnostic system

Check”

―