2007 ISUZU KB P190 fuse

11A-12 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)
Scan Tool Does Not Power Up
Circuit Description
The data link connector (DLC) is a standardized 16-
cavity connector. Connector design and location is
dictated by an industry wide standard, and is required
to provide the following:
• Scan tool power battery positive voltage at terminal 16.
• Scan tool power ground at terminal 4. • Common signal ground at terminal 5.
The scan tool will power up with the ignition OFF. Some
modules however, will not communicate unless the
ignition is ON.
Schematic Reference: Immobilizer Controls
Schematics
Connector End View Reference: ICU Connector End
View
Circuit/ System Testing Scan Tool Does Not Power Up
Step Action Value(s)Yes No
1 Important
: Make sure the scan tool works properly
on another vehicle before using this chart.
1. Turn OFF the ignition.
2. Inspect the Meter (+B) (10A) fuse in the cabin fuse block.
Is the Meter (+B) (10A) fuse open? —
Go to Step 2 Go to Step 3
2 Replace the Meter (+B) (10A) fuse. If the fuse
continues to open, repair the short to ground on
one of the circuits that is fed by the Meter (+B)
(10A) fuse or replace the shorted attached
component.
Did you complete the repair? —
Go to Step 7
—
31. Check each circuit at the data link connector
(DLC) (B-58) for a backed out, spread or
missing terminal.
2. Repair the terminal as necessary.
Did you find and complete the repair? —
Go to Step 7 Go to Step 4
4 Connect a test lamp between the +B circuit (pin 16
of B-58) at the DLC and a known good ground.
Does the test lamp illuminate? —
Go to Step 6 Go to Step 5
5 Repair the open in the battery voltage circuit to the
DLC.
Did you complete the repair? —
Go to Step 7
—
61. Test each ground circuit at the DLC (pins 4
and 5 of B-58) for an open circuit or high
resistance.
2. Repair the circuit(s), clean or tighten ground as necessary.
Did you find and correct the condition? —
Go to Step 7 Go to Intermittent
Conditions
7 1. Connect the scan tool to the DLC.
2. Attempt to turn ON the scan tool.
Does the scan tool ON? —
System OK Go to Step 1

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ISUZU KB P190 2007

IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6) 11A-19
Lost Communication with The Immobilizer Control Unit (ICU)
Circuit Description
The engine control module (ECM), transmission control
module (TCM) (AISIN A/T only) and ICU all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. (4JK1/ 4JJ1) The ECM, TCM, powertrain interface module (PIM) and
ICU all communicate with the scan tool over the CAN
link. (HFV6)
Schematic Reference: Immobilizer Controls
Schematics
Connector End View Reference: ICU Connector End
View
Circuit/ System Testing Lost Communication with The Immobilizer Control Unit (ICU)
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Immobilizer Controls? —
Go to Step 2 Go to Diagnostic
System Check - Immobilizer Controls
2 Attempt to establish communication with the ICU.
Does the scan tool communicate with the ICU? —
Go to Intermittent
Conditions Go to Step 3
3 1. Turn OFF the ignition.
2. Disconnect the scan tool from the data link connector (DLC) if connected.
3. Measure the resistance across the CAN Low and High circuits by probing the DLC (pins 6
and 14 of B-58).
Is the resistance within the specified value (parallel
resistance of the 120 Ω resistor in the ECM and the
120 Ω resistor in the ICU should be 60 Ω)? 50 to 70
Ω
Go to Step 5 Go to Step 4
4 1. Test the CAN Low and High circuits between
the ICU (pins 5 and 6 of B-109) and the data
link connector (DLC) (pins 6 and 14 of B-58)
for an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
5 1. Turn OFF the ignition.
2. Disconnect the ICU harness connector.
3. Connect a test lamp between the battery voltage feed circuit (pin 1 of B-109) and a
known good ground.
Does the test lamp illuminate? —
Go to Step 6 Go to Step 7
6 Connect a test lamp across the battery voltage feed
circuit and the ground circuit (pins 1 and 3 of B-
109)
Does the test lamp illuminate? —
Go to Step 9 Go to Step 8
7 Repair the open circuit or high resistance between
the Meter (+B) (10A) fuse and the ICU (pin 1 of B-
109).
Did you complete the repair? —
Go to Step 11
—
8Repair the open circuit or high resistance between
the ICU (pin 3 of B-109) and ground terminal.
Did you complete the repair? —
Go to Step 11
—

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ISUZU KB P190 2007

11A-20 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)
91. Turn OFF the ignition.
2. Disconnect the ICU harness connector.
3. Inspect for an intermittent, for poor connections and for corrosion at the harness
connector of the ICU (pins 1, 3, 5 and 6 of B-
109)
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
10 Important
: Replacement ICU must be
programmed.
Replace the ICU. Refer to ICU Replacement.
Did you complete the replacement? —
Go to Step 11
—
111. Turn OFF the ignition.
2. Reconnect all previously disconnected fuse or harness connector(s).
3. Turn the ignition ON, with the engine OFF.
4. Attempt to establish communication with the ICU.
Does the scan tool communicate with the ICU? —
System OK Go to Step 3
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

IMMOBILIZER SYSTEM (C24SE, 4JA1-T) 11A-27
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

Check the condition for system parts.
• Installation condition, poor connection, damage,
system parts malfunction. Harness, Fuse, Relay,
Immobilizer coil (antenna), Key, Meter, Immobilize
r
control unit (ICU), Engine control module (ECM).
NOTE: Breakage of immobilizer fuse does not operate
immobilizer system. Check engine 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.
• Immobilizer programming functions.
Must be programmed immobilizer system.
• Registration for security code, immobilizer control
unit parts number.
• Key switch operation.
Immobilizer system may detect a history DTC b
y
the timing of ON-OFF of a key switch.
• Active the immobilizer system.
• Keyless entry system is malfunction.
• Anti theft system is malfunction.

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


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ISUZU KB P190 2007

11A-32 IMMOBILIZER SYSTEM (C24SE, 4JA1-T)
NO IMMOBILIZER WARNING LAMP
Step Action Value(s) Yes No
1 Check the meter fuse for the instrument cluster
ignition feed circuit.
Is the fuse normal? 
Go to Step 3 Go to Step 2
2 Replace the fuse.
Is the action complete? 
Verify repair
Go to Step 3 

3 1. Key position is "OFF".
2. Disconnect the meter.
3. Disconnect the engine control module (ECM).
4. Check the circuit between meter and ECM for an open, short to round, or short to voltage.
Also, check the meter circuit for an open or short to
ground and the DLC ground circuit for an open.
W as a problem found? 
Go to Step 4 Go to Step 5
4 Repair or replace the meter circuit.
W as the action complete? 
Go to Step 5 
5 1. Key position is "ON," engine "OFF."
2. Observe the check engine lamp.
Is the check engine lamp "ON"? 
Go to Step 6 Go to Step 7
6 Repair or replace the meter.
W as the action complete? 
Go to Step 7 
7 1. Key position is "OFF".
2. Check the check engine lamp bulb.
Is the check engine lamp bulb normal? 
Go to Step 9 Go to Step 8
8 Replace the check engine lamp bulb.
Is the action complete? 
Verify repair
Go to Step 9 

9 1. Key position is "OFF".
2. Connect the meter.
3. Connect the engine control module (ECM).
4. Key position is "ON".
5. Observe the check engine lamp.
Note: If a key switch is turned ON, check engine lamp
will turn on and a check engine lamp will be turned off
after a few seconds.
Is the check engine lamp "ON"? 
Verify repair Go to Step 10
10 Replace the engine control module (ECM).
IMPORTANT: The replacement ICU must be
programmed the immobilizer data by scan tool.
W as the action complete? 
Verify repair 



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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

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