Isuzu KB P190. Manual — part 1439

9A1-74 RESTRAINT CONTROL SYSTEM

DTC B0063 (Flash Code 63) Battery Voltage Too Low

Step Action

Yes

Was the “SRS Diagnostic System Check” performed?

Go to Step 2

Go to the “SRS

Diagnostic System

Check”

1. Ignition switch is at “LOCK”.

2. Disconnect the SRS control unit.

3. Ignition switch “ON”.

4. Measure voltage on SRS control unit harness connector from

terminal “1” to terminal “3” (ground).

Is voltage on terminal “1” above 10.6V?

Go to Step 5

Go to Step 3

1. Ignition switch is at “LOCK”.

2. Remove and inspect “SRS” fuse to the “Ignition 1”.
Is fuse good?

Go to Step 4

Replace the "SRS"

fuse.

Go to Step 6

1. Ignition switch is at “LOCK”.

2. Measure resistance from "SRS" fusel to SRS control unit

harness connector terminal “1”.

Is resistance 5.0 ohms or less?

Inspect the

Charging System.

Refer to the

"Engine Electrical"

section.

Go to Step 6

Replace the SRS

harness.

Go to Step 6

1. Remove the "SRS" fuse.

2. Measure the resistance on the SRS control unit harness

connector as follow.

From terminals "1" to "3" and "23" (ground) (without the

pretensioner)

From terminals "1" to "3" and "15" (ground) (with the

pretensioner and the passenger air bag)

From terminals "1" to "3", "12" and "15" (ground) (with

the pretensioner and without the passenger air bag)

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

Ignition switch is at

“LOCK”.

Replace the SRS

control unit.

Go to Step 6

Replace SRS

Harness.

Go to Step 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”

―

RESTRAINT CONTROL SYSTEM 9A1-75

DTC B0071 (Flash Code 71) SRS Control Unit Internal Fault

RTW79ALF000301

Circuit Description

DTC B0071 is an indication of a potential internal SRS
control unit malfunction and will set if any of the
following conditions are detected:
1) Microprocessor energy reverse time failure.
2) EEPROM read / write failure.
3) ROM check sum.
4) Calibration check sum fault.
5) Inflators reserve voltage low.
6) Inflators electronic sensor active signal not detected

during commanded deployment.

7) QSDD (High-side/Low-side) FET failure.
8) Frontal accelerometer failure.
9) Phase lock loop lost lock.
10) QSDD communication fault.

DTC Will Set When

Any of the above indicated malfunctions are detected by
the SRS control unit. The malfunctions described
above are tested mainly during “Continuous Monitoring”
and some are run each ignition cycle.

Action Taken

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

DTC Will Clear When

The SRS control unit is replaced.

9A1-76 RESTRAINT CONTROL SYSTEM

DTC B0071 (Flash Code 71) SRS Control Unit Internal Fault

WARNING: DURING SERVICE PROCEDURES. BE VERY CAREFUL WHEN HANDLING A SRS CONTROL UNIT.
NEVER STRIKE OR JAR THE SRS CONTROL UNIT. NEVER POWER UP THE SRS WHEN THE SRS CONTROL
UNIT IS NOT RIGIDLY ATTACHED TO THE VEHICLE. ALL SRS CONTROL UNIT 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 SRS CONTROL UNIT COULD BE
ACTIVATED WHEN POWERED WHILE NOT RIGIDLY ATTACHED TO THE VEHICLE WHICH COULD CAUSE
DEPLOYMENT AND RESULT IN PERSONAL INJURY.
CAUTION: If DTC B0071 can not be cleared by Tech2, it is necessary to replace the SRS control unit.

Step Action

Yes

Was the “SRS Diagnostic System Check” performed?

Ignition switch

“LOCK”.

Replace SRS

control unit.

Repeat the “SRS

Diagnostic System

Check”

Go to the “SRS

Diagnostic System