check engine ISUZU TF SERIES 2004 Workshop Manual

11A-6 IMMOBILIZER SYSTEM

What happens without proper transponder
operation?
One of the function of transponder is to deactivate or
activate starter function. lf the proper transponder is not
used, starter cannot be operated. Because starter rela
y
stays off, cranking engine is not possible.
After the starter relay is activated, transponder signal
triggers to let lCU calculate by transponder address
signal and immobilizer algorithm.
When the result matches with necessary condition, it
makes injector power source be activated.
If transponder does not send correct signal, lCU and
ECM do not activate injector system on.
Therefore the vehicle cannot be operated.
No proper transponder is available, what
should be done for the system?
When any proper transponder is not available, a new
transponder should be programmed. Up to 5
transponders can be provided with a scan tool (Tech-2)
and by proper procedure.
In addition to the absence of proper transponder, it ma
y
happen particular secret code to the particular vehicle is
missing. ln this case, the secret code must be provided
by your organization.
Otherwise transponder cannot be programmed in an
y
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 ECM, new ICU and new transponder 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.
Caution to the operation
lf an attempt is made to start the engine while the
immobilizer system is activated, the check engine lamp
flashes and the engine will not start.
Summary of operation
Switch on: Set the ignition and starter switch to OFF.
(Activate)
Switch off: Set the ignition and starter switch to ON b
y
using the transponder key. (Deactivate)

What your organization should provide for
your customer





Car Pass

For a new owner, your dealership must hand Car Pass
card, which has identification numbers of new owner's
vehicle immobilizer system. This information is ver
y
important in case of repair or lost of transponder.
The followings are necessary items provided by you
r
responsibility.
1)
Car pass with identification for a new owner
2)
Blank car pass card when it is for reissue
3)
Instruction to dealers how to use car pass card






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 immobilizer 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.

11A-12 IMMOBILIZER SYSTEM

Pin-outs; For Electronic Control Engine (6VE1, C24SE, 4JH1-TC, 4JA1-TC)
RUW38HSF000201


No. Pin Function
A-1 Antenna coil positive
A-2


A-3 Antenna coil negative
B-1 Starter Relay (6VE1, C24SE Engine) / Immobilizer Relay (4JH1-TC/4JA1-TC Engine)
B-2 Ground
B-3 Voltage from ignition switch ON
B-4 Back up voltage supply
B-5 To Tech-2
B-6 Vehicle speed sensor (6VE1, C24SE Engine) / Not used (4JH1-TC/4JA1-TC Engine)
B-7 Communication: carry on line from ECM to ICU (Check engine lamp)
B-8 Communication: carry on line from ICU to ECM (Communication line W)

IMMOBILIZER SYSTEM 11A-15

Immobilizer coil (Antenna)
Immobilizer coil is install in order that ICU may check
the security code memorized by the transponder (key).

RUW38HSH000301
Transponder (Key)
Transponder is installed in the inside of a key.
Transponder has memorized the security code of a
immobilizer system.

LTW3BASH000101

Legend


(1) Transponder (Key)



Check engine lamp
Check engine lamp displays failure or a system
operation of a immobilizer system by flash of a lamp.

LTW3BASH000201
Engine control module (ECM)
ECM will stop engine, if it communicates with ICU and
abnormalities are detected by a key and the immobilize
r
system.

LTW3BASH000301

Legend


(1) ECM (6VE1 engine)

(2) ECM (C24SE engine)

(3) ECM (4JH1-TC engine)

IMMOBILIZER SYSTEM 11A-19

lmportant information on Programming
Security code
The security code protects the immobilizer control unit
against unauthorized programming and data access
from Tech-2. The security code consists of a 4 digit
code number and is programmed into the immobilize
r
control unit and Engine Control Module (ECM).
New control units are not programmed with a securit
y
code.
If the control units are replaced, the security code
entered in the car pass, transponder lD, etc.
Must be programmed into the new control unit with
Tech-2.
The security code can only be programmed with Tech-2
once and must therefore be performed with great care.
Once programmed, the security code cannot be
overwritten. An already used immobilizer can be reused
in a different car by initializing the immobilizer. After that
you can program the security code again. For initializing
command you need the current security code.
If the immobilizer control unit is returned, always
enclosed the security code that is allocated to that
control unit. If this is not done, we can not process the
case and the warranty will not be recognized.
Entering a code
If the Tech-2 display requests that the

security code


mechanical key number


Vehicle Identification No.
be entered, process as follows;
To input a digit you need to use the up and down
buttons of the Tech-2. By using the numeric buttons the
according digit will be displayed at the current position
and the cursor will move to the next position.
For letters you need to use the up and down buttons o
f
the Tech-2. The up and down key might be used for
digits as well. By using the up and down buttons the
displayed digit or letter will be increased or decreased.
To move to the next position you need to use the move-
to-right-button.
With the two buttons, move-to-right and move-to-left
you can select the position of number you want to
change.
This will allow you to correct a wrong number.
After the number is completed you need to press the
Enter button to accept the number. Correction is now no
longer possible.
Use the OKAY soft key to program the number and the
NOT OKAY soft key to abort the programming.
Transponder (Key)





If a transponder key is lost:
If a transponder key is lost, all transponder keys in the
immobilizer control system must be erased.
Transponder keys can be ordered via the "Your prope
r
organization name such as part and accessor
y
department" as previously by providing the mechanical
key number.
The mechanical key number is provided on the ca
r
pass.
Thereafter, existing and new transponder keys are
programmed consecutively using Tech-2. The vehicle
can then no longer be started using lost key.





5 transponder keys can be provided:

Each transponder has different Identifications. If a
customer wants more than 2 transponder keys,
maximum 5 transponder keys can be provided b
y
additional programming by Tech-2.






lf a new ignition key with different mechanical key
number needs to be installed:
If installation of an ignition lock with a different
mechanism key number is necessary (an ignition lock
which belongs to the mechanical key number has to be
ordered first), all transponder keys must first be erased
and the two transponder keys which belong to the
ignition lock that is now installed must be programmed.
The new mechanical key number must be programmed
now into the immobilizer. The mechanical key numbe
r
in the car pass is to be changed as well.
Important:
After successful programming, the engine control can
only be used for vehicles with immobilizer and
transponder.
Faults that occur in connection with the immobilize
r
control unit are recognized by the engine control unit
and as long as "IMMOBILOZER" is not programmed,
are indicated by a flashing of the check engine lamp.
If the immobilizer and engine control unit are replaced
at the same time, the immobilizer control unit must be
programmed first before the "IMMOBILIZER" function in
the engine control unit can be activated.

IMMOBILIZER SYSTEM 11A-31

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. When 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).
NOE: 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.

11A-34 IMMOBILIZER SYSTEM

IMMOBILIZER SYSTEM CHECK
Step Action Value(s) Yes No
1 1. Key position is "ON," engine "OFF."
2. Observe the check engine lamp.
Note: When 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"? 
Go to Step 2
Go to "No
Immobilizer
warning lamp"
2 1. Key position is "ON," engine "OFF."
2. Observe the check engine lamp.
Note: When 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 "OFF"?
(Check engine lamp does not flash) 
Go to Step 3
Go to
"Immobilizer
warning lamp on
steady"
3 1. Key position is "OFF."
2. Install a scan tool.
3. Key position is "ON."
4. Attempt to display immobilizer data with the scan
tool.
Does the scan tool display immobilizer data? 
Go to Step 9
Go to Step 4
4 1. Key position is "OFF," disconnect the immobilizer
control unit (ICU).
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.
Was a problem found? 
Go to Step 5
Go to Step 6
5 Repair or replace the DLC (Data Link Connector)
circuit.
Was the action complete? 
Go to Step 3 
6
1. 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.
2. If a problem is found, repair as necessary.
Was a problem found? 
Go to Step 7
Go to Step 8
7 Repair or replace the ICU ignition feed and ground
circuits.
Was the action complete? 
Go to Step 3 
8 Replace the immobilizer control unit (ICU).
IMPORTANT:
The replacement ICU must be
programmed the immobilizer data by the scan tool.
Was the action complete? 
Go to Step 3 
9 Select "Display DTCs" with the scan tool.
Are any DTCs stored? 
Go to Step 10
Go to Step 13

IMMOBILIZER SYSTEM 11A-35

Step Action Value(s) Yes No
10 Review and record for scan tool Failure Records data
and DTCs.
Was the action complete? 
Go to Step 11 
11 Following the DTC is stored.
Are there DTC B0001 or B0055 stored?
Go to applicable
DTC table after
Go to Step 12 Go to Step 12
12 Clear the DTCs by "Clear the Information "with scan
tool.
Did the DTCs Cleared? 
Go to Step 12 
13 Select "Display DTCs" with the scan tool.
Are any DTCs stored? 
Go to applicable
DTC table Go to Step 14
14 1. Key position is "ON," engine "OFF."
2. 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 "flash"? 
Go to Step 15
Go to Step 20
15 Check the engine control system.
If a problem is found, repair as necessary.
(Refer to section 6E: system check and DTCs)
IMPORTANT:
The replacement ECM must be
programmed the immobilizer data by scan tool.
(Except 4JA1-L Engine)
Was the action complete? 
Go to Step 16 
16 Check the key.
Is a key peculiar to a vehicle? 
Go to Step 18
Go to Step 17
17 Change into a peculiar key.
IMPORTANT:
If replace the key,
after replace lock
cylinders, perform the following below the items.

Replace the keys and key cylinders.

Program the immobilizer system.
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 18 
18 Check the immobilizer programming functions.


Immobilizer control unit (ICU).


Engine control module (ECM).


Transponder (Key).
If a problem is found, repair as necessary.
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 19

19 Operate the DTCs by "Clear the Information" with
scan tool.
Was the action complete? 
Go to Step 20 
20 Attempt to start the engine.
Did the engine start? 
System OK
Refer to
Diagnostic Aids

11A-36 IMMOBILIZER SYSTEM

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.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the meter circuit.
Was 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.
Was 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.
Was the action complete? 
Verify repair 

IMMOBILIZER SYSTEM 11A-37

CHECK IMMOBILIZER WARNING LAMP ON STEADY
Step Action Value(s) Yes No
1 1. Key position is "OFF".
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the engine control module (ECM).
4. Key position is "ON," engine "OFF."
5. Observe the check engine lamp.
Is the check engine lamp "ON"? 
Go to Step 2
Go to Step 5
2 1. Key position is "OFF".
2. Disconnect the meter.
3. Key position is "ON," engine "OFF."
4. Observe the check engine lamp.
Is the check engine lamp "ON"? 
Go to Step 3
Go to Step 4
3 Repair or replace the meter.
Was the action complete? 
Verify repair
Go to Step 5 

4 Repair or replace the meter circuit.
(Between meter and ICU/ECM)
Was the action complete? 
Verify repair
Go to Step 5 
5 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.
Was a problem found? 
Go to Step 6
Go to Step 7
6 Repair or replace the immobilizer unit (ICU) circuit.
Was the action complete? 
Verify repair
Go to Step 7 
7 1. Key position is "OFF".
2. Connect the meter.
3. Connect the immobilizer control unit (ICU).
4. Connect the engine control module (ECM).
5. Key position is "ON".
6. Observe the check engine lamp.
Is the check engine lamp "ON"? 
Verify repair
Refer to
Diagnostic Aids

IMMOBILIZER SYSTEM 11A-39

B0002 IMMOBILIZER NOT PROGRAMMED
Step Action Value(s) Yes No
1 Was the "Immobilizer System Check" performed?

Go to Step 2
Go to Immobilizer
System Check
2 Check the immobilizer programming functions.

Immobilizer control unit (ICU).
If a problem is found, repair as necessary.
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 3
Go to Step 5
3 Recheck the DTC.
1. Key position is “OFF” and keep the position for
more than 30 seconds.
2. Key position is “ON”.
3. Check the DTC on scan tool.
Is DTC B0002 stored? 
Go to Step 4
Verify repair
4 Replace the immobilizer control unit (ICU).
IMPORTANT:
The replacement ICU must be
programmed the security data by scan tool.
Was the action complete? 
Verify repair 
5 Check the immobilizer programming functions.


Engine control module (ECM).


Immobilizer control unit (ICU).
If a problem is found, repair as necessary.
(Refer to "Important information on Programming")
Was the action complete? 
Verify repair
Go to Step 6
6 Replace the key and lock cylinder assembly and
immobilizer system (ICU and ECM).
IMPORTANT:


ICU and ECM are not replacing simultaneously.


After replace lock cylinders, perform the following
below the items.


Program the immobilizer system.
(Refer to "Important information on Programming")
Was the action complete? 
Verify repair