check engine ISUZU TF SERIES 2004 Workshop Manual

IMMOBILIZER SYSTEM 11A-43

B0005 COMMUNICATION LINE W VOLTAGE LOW
Step Action Value(s) Yes No
1
Was 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 B0005 stored? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer communication W line circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the engine control module (ECM).
4. Check the immobilizer communication W line
circuit for an open, short to ground, or short to
voltage.
Also, check the ICU and ECM ignition feed circuits for
an open or short to ground and the ICU and ECM
ground circuit for an open.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the immobilizer communication W
line circuit.
Was 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.
Was the action complete? 
Verify repair 

11A-44 IMMOBILIZER SYSTEM

B0006 COMMUNICATION LINE W VOLTAGE HIGH
Step Action Value(s) Yes No
1
Was 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 B0006 stored? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer communication W line circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the engine control module (ECM).
4. Check the immobilizer communication W line
circuit for an open, short to ground, or short to
voltage.
Also, check the ICU and ECM ignition feed circuits for
an open or short to ground and the ICU and ECM
ground circuit for an open.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the immobilizer communication W
line circuit.
Was 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.
Was the action complete? 
Verify repair 

IMMOBILIZER SYSTEM 11A-45

B0007 NO ENGINE REQUEST RECEIVED
Step Action Value(s) Yes No
1
Was the "Immobilizer System Check" performed? 
Go to Step 2
Go to Immobilizer
System Check
2 Recheck the DTC on ICU.
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 B0007 stored? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer communication line circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the engine control module (ECM).
4. Check the immobilizer communication line circuit
for an open, short to ground, or short to voltage.
Also, check the ICU and ECM ignition feed circuits for
an open or short to ground and the ICU and ECM
ground circuit for an open.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the immobilizer communication line
circuit.
Was the action complete? 
Verify repair 
5 Recheck the DTC on ICU.
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 B0007 stored? 
Go to Step 6
Verify repair
6 Recheck the DTC on ECM.
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.
Are below DTCs stored?
P1649 (6VE1, C24SE) , P1611/P1614 (4JH1-TC) 
Go to Step 7
Go to Step 9
7 Perform the immobilizer programming functions.
(Refer to "Important information on Programming")


Engine control module (ECM).
Was the action complete? 
Go to Step 8
Go to Step 11
8 Recheck the DTC on ECM.
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.
Are below DTCs stored?
P1649 (6VE1, C24SE) , P1611/P1614 (4JH1-TC) 
Go to Step 11
Go to Step 12

11A-46 IMMOBILIZER SYSTEM

Step Action Value(s) Yes No
9 Check the immobilizer programming functions.

Engine control module (ECM).
If a problem is found, repair as necessary.
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 10
Go to Step 11
10 Recheck the DTC on ECM.
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.
Are below DTCs stored?
P1649 (6VE1, C24SE), P1611/P1614 (4JH1-TC) 
Go to Step 11
Go to Step 12
11 Replace the engine control module (ECM).
IMPORTANT:
The replacement ECM must be
programmed the security data by scan tool.
Was the action complete? 
Go to Step 12 
12 Recheck the DTC on ECM.
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.
Are below DTCs stored?
P1626 (6VE1, C24SE), P1612/P1613 (4JH1-TC) 
Go to Step 13
Go to Step 2
13 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


11A-50 IMMOBILIZER SYSTEM

B0011 TRANSPONDER KEY PROBLEM (Only 4JA1-T Engine)
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 key.
Is a key peculiar to a vehicle? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer programming functions.


All transponder (Key).
If a problem is found, repair as necessary.
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 4
Go to Step 5
4 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 B0011 stored? 
Go to Step 5
Verify repair
5 Recheck the DTC.
1. Non-OEM parts switch is "OFF" or remove the Non-
OEM parts.
2. Remove the accessory and another key from key.
3. Move the vehicle to a new location.
4. Key position is “OFF” and keep the position for more
than 30 seconds.
5. Key position is “ON”.
6. Check the DTC on scan tool.
Is DTC B0011 stored? 
Go to Step 6
Verify repair
6 Check the immobilizer coil (antenna) circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
(immobilizer coil circuit : 3 pin connector)
3. Check the immobilizer coil 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 7
Go to Step 8
7 Repair or replace the immobilizer coil (antenna) circuit.
Was the action complete? 
Verify repair 
8 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 B0011 stored? 
Go to Step 9
Verify repair

11A-52 IMMOBILIZER SYSTEM

B0012 WRONG TRANSPONDER KEY (Only 4JA1-T Engine)
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 key.
Is a key peculiar to a vehicle? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer programming functions.


Transponder (Key).
Was a problem found? 
Go to Step 4
Go to Step 5
4 Perform the immobilizer programming functions.


Transponder (Key).
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 5 
5 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 B0012 stored? 
Go to Step 6
Verify repair
6 Replace the transponder (Key).
IMPORTANT
: The replacement transponder (key)
must be programmed the security data by scan tool.
Was the action complete? 
Go to Step 7 
7 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 B0012 stored? 
Go to Step 8
Verify repair
8 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 

IMMOBILIZER SYSTEM 11A-53

B0013 IMMOBILIZER NOT PROGRAMMED (Only 4JA1-T Engine)
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 B0013 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 immobilizer unit.


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 Engine immobilizer
unit).
IMPORTANT:

ICU and Engine immobilizer unit 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 

11A-54 IMMOBILIZER SYSTEM

B0014 NO TRANSPONDER KEY PROGRAMMED (Only 4JA1-T Engine)
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 key.
Is a key peculiar to a vehicle? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer programming functions.


Transponder (Key).
Was a problem found? 
Go to Step 4
Go to Step 5
4 Perform the immobilizer programming functions.


Transponder (Key).
(Refer to "Important information on Programming")
Was the action complete? 
Go to Step 5 
5 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 B0014 stored? 
Go to Step 6
Verify repair
6 Replace the transponder (Key).
IMPORTANT:
The replacement transponder (key)
must be programmed the security data by scan tool.
Was the action complete? 
Go to Step 7 
7 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 B0014 stored? 
Go to Step 8
Verify repair
8 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 

IMMOBILIZER SYSTEM 11A-55

B0015 FREQUENCY SIGNAL LOW (Only 4JA1-T Engine)
Step Action Value(s) Yes No
1 Was 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 B0015 stored? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer communication W line circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the Engine immobilizer unit.
4. Check the immobilizer communication W line
circuit for an open, short to ground, or short to
voltage.
Also, check the ICU and Engine immobilizer unit
ignition feed circuits for an open or short to ground
and the ICU and Engine immobilizer unit ground
circuit for an open.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the immobilizer communication W
line circuit.
Was 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.
Was the action complete? 
Verify repair 

11A-56 IMMOBILIZER SYSTEM

B0016 FREQUENCY SIGNAL HIGH (Only 4JA1-L Engine)
Step Action Value(s) Yes No
1
Was 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 B0016 stored? 
Go to Step 3
Refer to
Diagnostic Aids
3 Check the immobilizer communication W line circuit.
1. Key position is “OFF”.
2. Disconnect the immobilizer control unit (ICU).
3. Disconnect the engine control module (Engine
immobilizer unit).
4. Check the immobilizer communication W line
circuit for an open, short to ground, or short to
voltage.
Also, check the ICU and Engine immobilizer unit
ignition feed circuits for an open or short to ground
and the ICU and Engine immobilizer unit ground
circuit for an open.
Was a problem found? 
Go to Step 4
Go to Step 5
4 Repair or replace the immobilizer communication W
line circuit.
Was 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.
Was the action complete? 
Verify repair