2007 ISUZU KB P190 engine

6E-218 Engine Control System (4JH1)
DTC P1611 (Symptom Code A) (Flash Code 56)
Circuit Description
The electronically erasable programmable read onl
y
memory (EEPROM) memorize immobilizer securit
y
code and secret key for communication with the
immobilizer control unit (ICU). If the engine control
module (ECM) detects wrong security code is
programmed into the ECM, this DTC will set.
Condition for Setting the DTC
• The ECM detects wrong immobilizer security code
is programmed.
Action Taken When the DTC Sets • The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The desired fuel injection quantity is set 0 mg/strk.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids • Programming ECM with wrong security code ma
y
set this DTC.
• ECM with wrong specification may set this DTC.

DTC P1611 (Symptom Code A) (Flash Code 56)


Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Select the “Immobilizer” in the system selection menu.
5. Monitor the Diagnostic Trouble Code (DTC) Info Ordered By Priority with the scan tool.
Does the immobilizer DTCs fail this ignition which
begin with B? 

Go to Applicable
DTC in Immobilizer Section Go to Step 3
3 Monitor the DTC Information with the scan tool. Does the DTC fail this ignition? 

Go to Step 4 Go to Diagnostic
Aids
4 Program or reprogram immobilizer function into the engine control module (ECM). Refer to Programming
Engine Control Module (ECM) in immobilizer section.
Did you find and correct the condition? 

Go to Step 6 Go to Step 5
5 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 6 
6 1. Clear the DTCs with the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 7
7 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-219
DTC P1612 (Symptom Code A) (Flash Code 56)
Circuit Description
The engine control module (ECM) communicates with
the immobilizer control unit (ICU) to execute immobilize
r
function. The ECM sends request signal to the ICU. The
ECM receives response signal from the ICU. Both
communication signals are carried out through the
Keyword 2000 serial data link. If the ECM receives
wrong response signal from the ICU, this DTC will set.
Condition for Setting the DTC
• The ECM receives wrong immobilizer response
signal from the ICU.
Action Taken When the DTC Sets • The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The desired fuel injection quantity is set 0 mg/strk.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids • Non programmed ECM may set this DTC.
• Electrical or magnetic interference may affect
intermittent condition.
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Notice: • Keyword 2000 serial data link circuit problem may
cause this DTC set. The scan tool will not
communicate. Refer to scan tool Does Not
Communicate with Keyword 2000 Device in this
section.
• ECM with wrong specification may set this DTC.

DTC P1612 (Symptom Code A) (Flash Code 56)

Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Select the “Immobilizer” in the system selection menu.
5. Monitor the Diagnostic Trouble Code (DTC) Info Ordered By Priority with the scan tool.
Does the immobilizer DTCs fail this ignition which
begin with B? 

Go to Applicable
DTC in Immobilizer Section Go to Step 3
3 Monitor the DTC Information with the scan tool. Does the DTC fail this ignition? 

Go to Step 4 Go to Diagnostic
Aids
4 Program or reprogram immobilizer function into the engine control module (ECM). Refer to Programming
Engine Control Module (ECM) in immobilizer section.
Did you find and correct the condition? 

Go to Step 6 Go to Step 5
5 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 6 
6 1. Clear the DTCs with the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 7
7 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK

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TO MODEL INDEX
ISUZU KB P190 2007

6E-220 Engine Control System (4JH1)
DTC P1613 (Symptom Code A) (Flash Code 56)
Circuit Description
The engine control module (ECM) communicates with
the immobilizer control unit (ICU) to execute immobilize
r
function. The ECM sends request signal to the ICU. The
ECM receives response signal from the ICU. Both
communication signals are carried out through the
Keyword 2000 serial data link. If the ECM does not
detect response signal from the ICU, this DTC will set.
Condition for Setting the DTC
• The ECM does not receive the immobilize
r
response signal from the ICU.
Action Taken When the DTC Sets • The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The desired fuel injection quantity is set 0 mg/strk.
Condition for Clearing the MIL/DTC • The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
• Non programmed ECM may set this DTC.
• Transponder key problem may set this DTC.
• Antenna coil problem may set this DTC.
• Electrical or magnetic interference may affect
intermittent condition.
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Notice: • Keyword 2000 serial data link circuit problem ma
y
cause this DTC set. The scan tool will not
communicate. Refer to scan tool Does Not
Communicate with Keyword 2000 Device in this
section.
• ECM with wrong specification may set this DTC.

DTC P1613 (Symptom Code A) (Flash Code 56)


Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Select the “Immobilizer” in the system selection menu.
5. Monitor the Diagnostic Trouble Code (DTC) Info Ordered By Priority with the scan tool.
Does the immobilizer DTCs fail this ignition which
begin with B? 

Go to Applicable
DTC in Immobilizer Section Go to Step 3
3 Monitor the DTC Information with the scan tool. Does the DTC fail this ignition? 

Go to Step 4 Go to Diagnostic
Aids
4 Program or reprogram immobilizer function into the engine control module (ECM). Refer to Programming
Engine Control Module (ECM) in immobilizer section.
Did you find and correct the condition? 

Go to Step 6 Go to Step 5
5 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 6 
6 1. Clear the DTCs with the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 7
7 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-221
DTC P1614 (Symptom Code A) (Flash Code 56)
Circuit Description
The engine control module (ECM) communicates with
the immobilizer control unit (ICU) to execute immobilize
r
function. The ECM sends request signal to the ICU. The
ECM receives response signal from the ICU. Both
communication signals are carried out through the
Keyword 2000 serial data link. If ICU receives wrong
immobilizer response signal from the transponder key,
this DTC will set.
Condition for Setting the DTC
• The ICU receives wrong immobilizer response
signal from the transponder key.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The desired fuel injection quantity is set 0 mg/strk.
Condition for Clearing the MIL/DTC • The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids • Non programmed ICU may set this DTC.
• Transponder key problem may set this DTC.
• ECM with wrong specification may set this DTC.

DTC P1614 (Symptom Code A) (Flash Code 56)

Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Select the “Immobilizer” in the system selection menu.
5. Monitor the Diagnostic Trouble Code (DTC) Info Ordered By Priority with the scan tool.
Does the immobilizer DTCs fail this ignition which
begin with B? 

Go to Applicable
DTC in Immobilizer Section Go to Step 3
3 Monitor the DTC Information with the scan tool. Does the DTC fail this ignition? 

Go to Step 4 Go to Diagnostic
Aids
4 Program or reprogram immobilizer function into the immobilizer control unit (ICU). Refer to Programming
Immobilizer Control Unit (ICU) in immobilizer
section.
Did you find and correct the condition? 

Go to Step 6 Go to Step 5
5 Important: Replacement ICU must be programmed.
Replace the ICU. Refer to Immobilizer Control Unit
(ICU) Replacement in the immobilizer section.
Did you complete the replacement? 

Go to Step 6 
6 1. Clear the DTCs with the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 7
7 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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TO MODEL INDEX
ISUZU KB P190 2007

6E-222 Engine Control System (4JH1)
DTC P1625 (Symptom Code A) (Flash Code 76)
Circuit Description
The engine control module (ECM) main relay is
energized when the ECM receives an ignition voltage
switch ON signal. W hen the ignition switch is OFF, the
ECM main relay is de-energized after a certain length o
f
time passed. If the ECM detects the ECM main relay is
turned OFF before ECM commanded OFF, this DTC
will set.
Condition for Setting the DTC
• The ECM detects that the ECM main relay is
turned OFF before commanded turned OFF.
Action Taken When the DTC Sets • The ECM does not illuminate the malfunction
indicator lamp (MIL) when the diagnostic runs and
fails.
Condition for Clearing the DTC
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
• Faulty ECM main relay may set this DTC.

DTC P1625 (Symptom Code A) (Flash Code 76)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
5. Turn OFF the ignition.
6. Turn ON the ignition, with the engine OFF.
Does the DTC fail this ignition? 

Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition. 2. Disconnect the ECM main relay.
3. Inspect for an intermittent, for poor connections and corrosion at the harness connector of the
ECM main relay (pins 1, 2, 4 and 5 of X-12
connector).
4. Disconnect the engine control module (ECM) harness connector.
5. Inspect for an intermittent, for poor connections and corrosion on ECM main relay control and
battery voltage feed circuit at the harness
connector of the ECM (pins 3 and 58 of C-56
connector).
6. Test for high resistance on each ECM main relay circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 5 Go to Step 4
4 Replace the ECM main relay. Did you complete the replacement? 

Go to Step 5 

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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-223
Step Action Value(s) Yes No
5 1. Reconnect all previously disconnected relay or
harness connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Observe the DTC Information with the scan tool.
6. Turn OFF the ignition.
7. Turn ON the ignition, with the engine OFF.
Does the DTC fail this ignition? 

Go to Step 3 Go to Step 6
6 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK





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TO MODEL INDEX
ISUZU KB P190 2007

6E-224 Engine Control System (4JH1)
DTC P1625 (Symptom Code B) (Flash Code 76)
Circuit Description
The engine control module (ECM) main relay is
energized when the ECM receives an ignition voltage
switch ON signal. W hen the ignition switch is OFF, the
ECM main relay is de-energized after a certain length o
f
time passed. If the ECM detects the ECM main relay
has been ON since the ignition switch was turned OFF,
this DTC will set.
Condition for Running the DTC
• The ignition switch is OFF.
Condition for Setting the DTC • The ECM detects that the ECM main relay is
turned ON for longer than 2 seconds.
Action Taken When the DTC Sets • The ECM does not illuminate the malfunction
indicator lamp (MIL) when the diagnostic runs and
fails.
Condition for Clearing the DTC
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
• Faulty or sticking ECM main relay may set this
DTC.
Test Description
The numbers below refer to the step number on the
diagnostic table.
2. If this DTC is present, scan tool can communicate
with the ECM when the ignition switch is OFF.

DTC P1625 (Symptom Code B) (Flash Code 76)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls? 
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
Does the DTC fail with the ignition switch OFF? 

Go to Step 3 Go to Diagnostic
Aids
3 1. Disconnect the ECM main relay. 2. Monitor the DTC Information with the scan tool.
Does the DTC fail with the ignition switch OFF? 

Go to Step 6 Go to Step 4
4 1. Turn OFF the ignition. 2. Disconnect the ECM main relay.
3. Connect a test lamp between the control circuit of the ECM main relay harness (pin 4 of X-12
connector) and battery voltage.
4. Keep the ignition switch OFF.
Does the test lamp illuminate? 

Go to Step 5 Go to Step 7
5 1. Test the control circuit of the ECM main relay between the engine control module (ECM) (pin
58 of C-56 connector) and the ECM main relay
(pin 4 of X-12 connector) for a short to ground.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 9 Go to Step 8
6 Repair the short to battery on the voltage feed supply circuit to the ECM between the ECM (pin 3 of
C-56 connector) and the ECM main relay (pin 1 of X-
12 connector).
Did you complete the repair? 

Go to Step 9 
7 Replace the ECM main relay.
Did you complete the replacement? 

Go to Step 9 

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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-225
Step Action Value(s) Yes No
8 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 9 
9 1. Reconnect all previously disconnected relay or
harness connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Monitor the DTC Information with the scan tool.
Does the DTC with the ignition switch OFF? 

Go to Step 3 Go to Step 10
10 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007