Isuzu KB P190. Manual - part 1437

9A1-66  RESTRAINT CONTROL SYSTEM 

 

DTC B0055 (Flash Code 55) Vehicle Variant Missing 

 
 

 

 

RTW79ALF000301 

 

 
 

Circuit Description 

DTC B0055 will be set, if either the SRS control unit or 
the SRS control unit harness is not genuine parts. 
The correct conditions of terminals on the SRS control
unit and the SRS harness are as follows. 
 

 

 

Terminal No. 

 

12 15 23 26 

Without 
Pretensioner 

- - 

used

- 

With Pretensioner 

- 

used 

- 

- 

With Pretensioner 
and Without 
Passenger Air Bg 

used used  - 

- 

 

RESTRAINT CONTROL SYSTEM  9A1-67 

 

 

 

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. Ignition switch is at “LOCK”. 

 2. Disconnect the SRS control unit. 

 

3. 

Inspect the SRS control unit harness for the following 
condition. 

  Without the pretensioner: 

-  The wiring harness is not connected on terminal "23" 

-  The wiring harness is connected on terminals "12", "15" 

and "26" 

  With the pretensioner: 

-  The wiring harness is not connected on terminal "15" 

-  The wiring harness is connected on terminals "12", "23" 

and "26" 

  Without the pretensioner and without the passenger air 

bag: 

-  The wiring harness is not connected on terminals "12" 

and "15" 

-  The wiring harness is connected on terminals "23" and 

"26" 

Was a problem found? 

Replace the SRS 

control unit 

harness. 

Go to Step 3 

Replace the SRS 

control unit. 

Go to Step 3 

3 

 1. Reconnect all components and ensure all components are 

properly mounted. 

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

Go to the “SRS 

Diagnostic System 

Check”  

― 

 

 

DTC Will Set When 

  Without the pretensioner:   

Terminals "12", "15" and "26" are shorted to
ground. 
Terminal "23" is open (harness is not connected).

  With the pretensioner: 

 

Terminals "12", "23" and "26" are shorted to
ground. 
Terminal "15" is open (harness is not connected).

  With the pretensioner and without the passenger

air bag: 

 

Terminals "23" and "26" are shorted to ground.
Terminals "12" and "15" are open (harness is not
connected). 

It is DTC set, if non genuine SRS control unit is installed
with the SRS harness genuine part, or incase of
terminal "12", "15", "23" and "26" are abnormal
condition with the SRS control unit genuine part. 

 

 

Action Taken 

The SRS control unit turns “ON" the “SRS" warning 
lamp and sets a DTC B0055. 
But if there is abnormal condition with the SRS control 
unit and/or SRS harness, the DTC is not set. 
 

DTC Will Clear When 

DTC B0055 can be cleared only by using the scan tool.
 

Diagnostic Aids 

Ensure that terminal "12" is shorted to ground on the
SRS harness. Terminal "15", "23" and "26" are open 
circuit. 

DTC B0055 (Flash Code 55) Vehicle Variant Missing 

9A1-68  RESTRAINT CONTROL SYSTEM 

 

DTC B0061 (Flash Code 61) Warning Lamp Circuit Failure 

 
 

 

 

RTW79ALF000301 

 

Circuit Description 

When the ignition switch is first turned “ON”, “Ignition 1”
voltage is applied from the “METER” fuse to the “SRS” 
warning lamp which is connected to “SRS" warning 
lamp, terminal “4”.  The “SRS” fuse applies system 
voltage to the “Ignition 1” inputs, terminal “1”.  The SRS
control unit responds by flashing the “SRS” warning 
lamp 7 times. The SRS control unit monitors the “SRS
Warning Lamp" terminal "4" for conditions that are 
incorrect for the commanded state of the "SRS" warning
lamp. 
For example, a failure condition exists if the SRS 
control unit detects low voltage when the "SRS" warning
lamp is commanded OFF, or high voltage when the
"SRS" warning lamp is commanded ON. If the SRS 
control unit detects an improper voltage on the “SRS
Warning Lamp" terminal "4", DTC B0061 will set. 

 

DTC Will Set When 

The SRS control unit try to turn "ON" the "SRS" warning
lamp but the battery voltage is not supplied to terminal 
"4". 
The SRS control unit try to turn "OFF" the "SRS"
warning lamp but the battery voltage is supplied to
terminal "4". 
 

Action Taken 

If circuits of the “SRS" warning lamp power supply and
ground are normal condition, the SRS control unit turns 
“ON” the “SRS” warning lamp and sets a diagnostic 
trouble code. 
 

RESTRAINT CONTROL SYSTEM  9A1-69 

 

DTC Will Clear When 

The malfunction is no longer occurring and the ignition
is turned to “LOCK”.  

DTC Chart Test Description 

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

malfunctioning 

5.  This test determines whether the malfunction is in

the “SRS Warning Lamp” circuit. 

7.  This test determines whether the SRS control unit is

malfunctioning 

 

 

8.  This test determines whether the malfunction is in 

the “SRS Warning Lamp” circuit. 

9.  This test determines whether the malfunction is in 

the power supply circuit of the "SRS" warning lamp.

 

Diagnostic Aids 

The warning lamp turns “ON" without relation SRS
control unit, and turn the warning lamp “OFF" due to 
electric current to SRS control unit. 

 

 

DTC B0061 (Flash Code 61) Warning Lamp Circuit Failure 

 

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. Ignition switch is at “ON”. 

 2. Note the “SRS” warning lamp. 
Does the “SRS” warning lamp flash seven 7 times? 

Repeat the “SRS 

Diagnostic System 

Check” 

Go to Step 3 

3 

Did the “SRS” warning lamp come “ON” steady at Step 2?  

Go to Step 4 

Go to Step 6 

4 

 1. Ignition switch is at “LOCK”. 

 2. Disconnect the SRS control unit. 

 3. Ignition switch is at “ON”. 

 4. Note the “SRS” warning lamp. 
Does the “SRS” warning lamp go “OFF”? 

Ignition switch is at 

“LOCK”. 

Replace the SRS 

control unit . 

Go to Step 10 

Go to Step 5 

5 

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

  From terminals "4" to "3" and "23" (ground) (without the 

pretensioner) 

  From terminals "4" to "3" and "15" (ground) (with the 

pretensioner and the passenger air bag) 

  From terminals "4" to "3", "12" and "15" (ground) (with 

the pretensioner and without the passenger air bag) 

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

Service instrument 

meter cluster. 

Install instrument 

meter cluster. 

Go to Step 10 

Replace the SRS 

harness. 

Go to Step 10 

6 

 1. Ignition switch is at “LOCK”. 

 2. Remove and inspect “METER” fuse to the “SRS” warning 

lamp.  

Is the fuse good? 

Go to Step 7 

Replace the 

"METER" fuse. 

Go to Step 10 

7 

 1. Disconnect the SRS control unit. 

 2. Ignition switch is at “ON”. 

 

3. 

Measure the voltage on the SRS control unit harness 
connector from terminal “4” to terminal “3” (ground). 

Is system voltage present on terminal “4”? 

Ignition switch is at 

“LOCK”. 

Replace the SRS 

control unit. 

Go to Step 10 

 

Go to Step 8