check engine ISUZU KB P190 2007 Workshop Repair Manual

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