2007 ISUZU KB P190 ignition

IMMOBILIZER SYSTEM (C24SE, 4JA1-T) 11A-55
B0055 EEPROM ERROR
Step Action Value(s) Yes No
1
W as the "Immobilizer System Check" performed? 
Go to Step 2 Go to Immobilizer
System Check
2 Recheck the DTC.
1. Key position is “OFF”.
2. Install the scan tool on vehicle.
3. Key position is “ON”.
4. Check the DTC on scan tool.
Is DTC B0055 stored? 
Go to Step 3 Refer to
Diagnostic Aids
3 Check the immobilizer control unit (ICU) circuit.
1. Ignition "OFF," disconnect the ICU.
2. Check the ICU circuit for an open, short to ground, or short to voltage.
Also, check the ICU ignition feed circuit for an open or
short to ground and the ICU ground circuit for an
open.
W as a problem found? 
Go to Step 4 Go to Step 5
4 Repair or replace the immobilizer unit (ICU) circuit.
W as the action complete? 
Verify repair 
5 Replace the immobilizer control unit (ICU).
IMPORTANT: The replacement ICU must be
programmed the security data by scan tool.
W as the action complete? 
Verify repair 



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ISUZU KB P190 2007

11B-4 ANTITHEFT SYSTEM
Transmitter (into remote key) power
The transmitted power is less than 10 m W .
Battery life time for transmitter power
The minimum life time of battery is 2 years with 15
lock/unlock cycles per day.
W hile the battery is changed, the data retention will be
at least 3 minutes without pressing a button.
Super lock
(Mechanical anti-theft locking system)
To Lock:
All doors must be closed; press the lock button on the
remote control unit again within 10 seconds after
locking or turn key in driver's door lock towards rear of
vehicle again within 10 seconds after locking, then turn
it back to the vertical position and remove.
Lock buttons on all doors are positioned such that doors
cannot be opened.
To unlock:
Press unlock button on remote key or turn key in
driver's door lock towards front of vehicle, then turn it
back to the vertical position and remove. If the key is
used, antitheft alarm sound operate which continues
until ignition switch turn ON. If a problem is found, open
the driver door as necessary.


No proper transmitter is available, what
should be done for the system?
W hen any proper transmitter is not available, a new
transmitter should be programmed. Up to 5 transmitters
can be provided with a scan tool (Tech-2) and by proper
procedure.
In addition to the absence of proper transmitter, it may
happen particular secret code to the particular vehicle is
missing. ln this case, the secret code must be provided
by your organization.
Otherwise transmitter cannot be programmed in any
way.
lf the essential for a scan tool (Tech-2) for programming
and proper software for Tech-2 are not available, there
is no permanent way to fix system. Temporary replace
with new ACU, new ICU and new transmitter without
any secret code can make the system be deactivated,
but it does not last long. Such a replacement does not
solve any condition. Even after replacement, the system
is activated automatically in short time and then no
operation of the vehicle can be made in any way.
Tech-2 should be provided in your organization.

• Security code management
Your organization must keep security codes for all
vehicles as confidential data. Once the security codes
are lost, anybody who have the security code can
access antitheft system. Your organization has
responsibility of any missing vehicles caused by stolen
security code.

• Essential tool (Scan tool: Tech-2)
Your dealership must have Tech-2, and Tech-2 updated
software for immobilizer system.


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ISUZU KB P190 2007

11B-36 ANTITHEFT SYSTEM

Diagnosis
Diagnostic procedure
• Once the cause of DTC is repaired or gone,
engine can be operated normally, and present
DTC becomes history code.
• History code is canceled by no repeat failure on 25
consequence ignition key on afterward.
• History code cannot be canceled by batter
y
connector disconnected.
Clearing Diagnostic Trouble Codes
IMPORTANT: Do not clear DTCs unless directed to do
so by the service information provided for each
diagnostic procedure. W hen DTCs are cleared, the
Failure Record data which may help diagnose an
intermittent fault will also be erased from memory.
Verifying Vehicle Repair
Verification of vehicle repair will be more
comprehensive for vehicles with immobilizer system
diagnostic. Following a repair, the technician should
perform the following steps:
1. Review and record the Fail Records for the DTC which has been diagnosed.
2. Clear DTC (s).
3. Operate the vehicle within conditions noted in the Fail Records.
4. Monitor the DTC status information for the DTC which has been diagnosed until the diagnostic test
associated with that DTC runs.
Following these steps are very important in verifying
repairs on immobilizer systems. Failure to follow these
steps could result in unnecessary repairs.
Diagnostic Aids
An intermittent may be caused by the following:
• Poor connections.
• Miss routed harness.
• Rubbed through wire insulation.
• Broken wire inside the insulation.
Check for the following conditions:
• Poor connection at ACU-Inspect harness
connectors for backed out terminals, imprope
r
mating, broken locks, improperly formed or
damaged terminals, and poor terminal to wire
connection.
• Damaged harness-Inspect the wiring harness fo
r
damage.
If the harness appears to be OK, observe the data
display on the Tech2 while moving connectors and
wiring harnesses related to the switch or actuator.

A change in the display will indicate the location of
the fault.
If DTC cannot be duplicated, the information included in the Failure Records data can be useful
in determined vehicle mileage since the DTC was
last set.
If it is determined that the DTC occurs intermittently, performing the DTC Diagnostic
Chart may isolate the cause of the fault.
NOTE: Breakage of antitheft fuse does not operate
antitheft system. Check LED lamp flashes at this time.

Check the Electro-Magnetic Interference (EMI)
• Location of vehicle check
Move the vehicle to a new location and perform
the check again.
• Non-OEM Parts.
Switch is “OFF” or remove the Non-OEM parts and
perform the check again.
• Other
Remove the accessory and another key from key.

Check the other items.
• Battery voltage is low.
• Antitheft programming functions.
Must be programmed antitheft system.
• Registration for security code, antitheft control unit
parts number.
• Key switch operation.

Antitheft system may detect a history DTC by the
timing of ON-OFF of a key switch.
• Active the antitheft system.
• Keyless entry system is malfunction.
• Immobilizer system is malfunction.

Check the operation
Check the operation "Lock / unlock" by using transmitter
(key) on the vehicle.


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ISUZU KB P190 2007

11B-38 ANTITHEFT SYSTEM
Antitheft System Check
Step Action Value (s) Yes No
1
1. Key position is “ACC”, shut all doors and bonnet.
2. Observe the antitheft lamp.
Note: W hen a key switch is “ACC”, antitheft lamp will
turn on and a antitheft lamp (LED) will be flashing
after 10 seconds.
Is the antitheft lamp "ON” or flashing? — Go to Step 2 Go to
“No antitheft lamp”
2
1. Key position is “ON”, engine “OFF”.
2. Observe the antitheft lamp.
3. Key position is turned “ACC”.
4. Check the antitheft lamp will be turned flashing and lamp will be turned ACC after 10 seconds.
Is the antitheft lamp flashing? — Go to
DTC table Go to Step 3
3
1. Key position is “OFF”.
2. Install the Tech-2.
3. Key position is “ON” or “OFF”.
4. Attempt to display antitheft data with the Tech-2.
Does the Tech-2 display antitheft data? — Go to Step 9 Go to Step 4
4
1. Key position is “OFF”, disconnect the antitheft
control unit (ACU).
2. Check the DLC (Data Link Connector) circuit for an open, short to ground, or short to voltage.
Also, check the DLC ignition feed circuit for an open
or short to ground and the DLC ground circuit for an
open.
W as a problem found? — Go to Step 5 Go to Step 6
5 Repair or replace the DLC (Data Link Connector)
circuit.
W as the action complete? — Go to Step 3 —
6
1 Check the ACU ground circuit for an open, or
short to voltage. Also, check the ACU ignition feed
circuit for an open or short to ground and the ACU
ground circuit for an open.
2 If a problem is found, repair as necessary.
W as the problem found? — Verify repair Go to Step 7
7
Replace the antitheft control unit (ACU).
IMPORTANT: The replacement ACU must be
programmed the antitheft data by Tech-2.
W as the action complete? — Go to Step 8 —
8 Select “Display DTCs” with the Tech-2.
Are any DTCs stored? — Go to applicable
DTC table —
9
1 Observe the antitheft data list on Tech-2.
2 If a problem is found, repair as necessary.
W as the problem found? — System OK Go to
applicable sectio n


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ISUZU KB P190 2007

ANTITHEFT SYSTEM 11B-39
No Antitheft Lamp
Step Action Value (s) Yes No
1 Check the fuse for the antitheft power feed circuit.
(10A)
If a problem found, repair as necessary.
W as the problem found?
Is the action complete? — Verify repair Go to Step 2
2
1. Check the ACU ground circuit for an open, or
short to voltage. Also, check the ACU ignition feed
circuit for an open or short to ground and the ACU
ground circuit for an open.
2. If a problem is found, repair as necessary.
W as the problem found? — Verify repair Go to Step 3
3
1. Check the antitheft lamp LED circuit for an open,
or short to voltage.
2. If a problem is found, repair as necessary.
W as the problem found? — Verify repair Go to Step 4
4
1. Key position is “OFF”.
2. Install the Tech-2.
3. Key position is “ACC” or “OFF”.
4. Observe to display lamp data with the Tech-2.
Does the Tech-2 display antitheft lamp data ON? — Go to Step 5 Go to Step 6
5 Replace the antitheft lamp. — Verify repair —
6 Replace the antitheft control unit (ACU).
IMPORTANT: The replacement ACU must be
programmed the antitheft data by Tech-2.
W as the action complete? — Verify repair —


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ISUZU KB P190 2007

ANTITHEFT SYSTEM 11B-43
DTC 20 Broken wire to door lock actuators
Step Action Value (s) Yes No
1 W as the Antitheft System Check performed?
— Go to Step 2 Go to
antitheft
System Check
2 Recheck the DTC.
1. Key position is “OFF”.
2. Install the Tech-2 on vehicle.
3. Key position is “ON”.
4. Check the DTC on the Tech-2.
Is DTC 20 stored? — Go to Step 3 Refer to
Diagnostic Aids
3 Check the door lock actuator circuit.
1. Key position is “OFF”.
2. Disconnect the antitheft control unit (ACU).
3. Disconnect the door lock motor.
4. Check the antitheft/door lock motor line circuit for an open, short to ground.
Also, check the ignition feed circuits for an open or short to ground and the ACU ground circuit for
an open.
W as a problem found? — Go to Step 4 Go to Step 5
4 Repair or replace the antitheft/door lock motor circuit.
W as the action complete? — Verify repair —
5 Replace the antitheft control unit (ACU).
IMPORTANT: The replacement ACU must be
programmed the security data by the tech2.
W as the action complete? — Verify repair —


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ISUZU KB P190 2007

ANTITHEFT SYSTEM 11B-49
DTC 28 Input Immobilizer short circuit to ground
Step Action Value (s) Yes No
1 W as the Antitheft System Check performed?
— Go to Step 2 Go to
antitheft
System Check
2 Recheck the DTC.
1. Key position is “OFF”.
2. Install the Tech-2 on vehicle.
3. Key position is “ON”.
4. Check the DTC on the Tech-2.
Is DTC 28 stored? — Go to Step 3 Refer to
Diagnostic Aids
3 Check the driver door locking motor function.
line circuit.
1. Key position is “OFF”.
2. Install the Tech-2 on vehicle.
3. Key position is “ON”.
4. Check the antitheft/Immobilizer communication line circuit for short to voltage, short to ground.
Also, check the ICU and ACU ignition feed circuits for an open or short to ground and the ICU and
ACU ground circuit for an open.
W as a problem found? — Go to Step 4 Go to Step 5
4 Repair or replace the antitheft/Immobilizer
communication line circuit.
W as the action complete? — Verify repair —
5 Replace the antitheft control unit (ACU). IMPORTANT: The replacement ACU must be
programmed the security data by the Tech-2.
W as the action complete? — Verify repair —


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ISUZU KB P190 2007

11B-50 ANTITHEFT SYSTEM
DTC 29 Broken Wire To Immobilizer
Step Action Value (s) Yes No
1 W as the Antitheft System Check
performed? — Go to Step 2 Go to
antitheft
System Check
2 Recheck the DTC.
1. Key position is “OFF”.
2. Install the scan tool on vehicle.
3. Key position is “ON”.
4. Check the DTC on the Tech-2.
Is DTC 29 stored? — Go to Step 3 Refer to
Diagnostic Aids
3 Check the antitheft/immobilizer communication line circuit.
1. Key position is “OFF”.
2. Disconnect the antitheft control unit (ACU).
3. Disconnect the immobilizer control unit (ICU).
4. Check the antitheft/Immobilizer communication line circuit for an open, short to ground.
Also, check the ICU and ACU ignition feed circuits for
an open or short to ground and the ICU and ACU
ground circuit for an open.
W as a problem found? — Go to Step 4 Go to Step 5
4 Repair or replace the antitheft/Immobilizer
communication line circuit.
W as the action complete? — Verify repair —
5 Replace the antitheft control unit (ACU). IMPORTANT: The replacement ACU must be
programmed the security data by the Tech-2.
W as the action complete? — Verify repair —


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ISUZU KB P190 2007