2007 ISUZU KB P190 fault code reset

6E-64 Engine Control System (4JH1)
DTC
(Symptom Code) Flash
Code MIL
Status DTC Name on
scan tool Condition for
Running the DTC Condition for
Setting the DTC Possible Cause
P1625
(B) 76 OFF ECM Main Relay
Circuit •
The ignition switch
is OFF. •
The ECM detects
that the ECM main
relay is turned ON
for longer than 2
seconds. •
ECM main relay control circuit is
short to ground.
• ECM battery voltage circuit is
short to battery.
• Faulty ECM main relay.
• Faulty ECM.

P1630 (A) 51 ON Injection Pump
Fuel Metering
Control
 •
The ECM detects
that the PCU
monitored fuel
injection solenoid
valve control
current is too high.
•
Faulty fuel injection pump.
• Faulty PCU.

P1630 (B) 51 ON Injection Pump
Fuel Metering
Control
 •
The ECM detects
that the PCU
continuously flow
the control current
to the fuel injection
solenoid valve.
•
Faulty fuel injection pump.
• Faulty PCU.

P1650 (A) 44 ON CAN Device
Offline
 •
The ECM detects
that the PCU
receives from the
CAN controller
reset or Bus Offline.
•
CAN high circuit is open circuit,
high resistance, short to ground,
short to battery or ignition
voltage.
• CAN low circuit is open circuit,
high resistance, short to ground,
short to battery or ignition
voltage.
• Electrical interference.
• Magnetic interference.
• Faulty PCU.
• Faulty ECM.

P1650 (B) 44 ON CAN Device Hang-
up
 •
The ECM detects
internal CAN
controller does not
react.
•
Faulty ECM.


P1651 (A) 45 ON CAN Malfunction
 •
The ECM detects
that the PCU does
not receive the CAN
messages from the
ECM.
•
CAN high circuit is open circuit,
high resistance, short to ground,
short to battery or ignition
voltage.
• CAN low circuit is open circuit,
high resistance, short to ground,
short to battery or ignition
voltage.
• Electrical interference.
• Magnetic interference.
• Faulty PCU.
• Faulty ECM.


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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-227
DTC P1650 (Symptom Code A) (Flash Code 44)
Circuit Description
The engine control module (ECM) calculates the
desired fuel injection quantity and timing using data sent
from various sensors. These desired data are sent to
the fuel injection pump control unit (PCU) via a
controller area network (CAN) communication bus. The
PCU also receives signals from the internal inputs:
pump camshaft position (CMP) sensor that is located
inside the fuel injection pump to determine the cam ring
rotation angle and the fuel injection pump speed. The
fuel temperature (FT) sensor is internal the PCU. These
values are used to compare the desired values sent
from the ECM then PCU determines the injection time
r
piston position and fuel injection quantity, and actuates
timing control valve (TCV) & fuel injection solenoid
valve based on control maps in the PCU.
The ECM monitors CAN operational status by expecting
a constant flow of messages from the PCU. If the ECM
detects that the PCU receives from the CAN controlle
r
rest or Bus Offline, this DTC will set.
Condition for Setting the DTC
• The ECM detects that the PCU receives from the
CAN controller reset or Bus Offline.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The ECM cuts the fuel injection.
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
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.

DTC P1650 (Symptom Code A) (Flash Code 44)
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.
Is DTC P1651 (Symptom Code A or B) set? 

Go to Applicable DTC 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 1. Turn OFF the ignition. 2. Disconnect the fuel injection pump control unit (PCU) harness connector.
3. Connect a DMM across the controller area network (CAN) harness (pins 1 and 2 of E-6
connector).
4. Measure the resistance across the CAN terminals.
Is the resistance within the specified value? 110-130
Ω
Go to Step 5 Go to Step 10
5 1. Connect a DMM between the CAN Low signal circuit (pin 1 of E-6 connector) and a known good
ground.
2. Turn ON the ignition, with the engine OFF.
Is the DMM voltage within the specified value? 1.5 – 2.5 volts
Go to Step 6 Go to Step 11
6 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a DMM between the CAN High signal circuit (pin 2 of E-6 connector) and a known good
ground.
Is the DMM voltage within the specified value? 3.0 – 4.0 volts
Go to Step 7 Go to Step 12

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ISUZU KB P190 2007

6E-52 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Desired EGR Position
This parameter displays EGR position desired by the
ECM based on current driving conditions. This can be
compared to the actual EGR position to determine
sensor accuracy or EGR control problems.
EGR Position
This parameter displays the EGR valve position
calculated by the ECM using the signal from EGR
position sensor. The scan tool will display a low
percentage when the EGR valve is closed, and a high
percentage when the ERG valve is opened.
EGR Position Sensor
This parameter displays the voltage signal sent to the
ECM from the EGR position sensor. EGR position
sensor is a range of value indicating a low voltage
when the EGR valve is closed, and a high voltage when
the EGR valve is opened.
Intake Throttle Solenoid Command
This parameter displays the intake throttle solenoid
valve control duty ratio based on inputs to the ECM
from various engine sensors. The scan tool will display
a lower percentage when the intake throttle solenoid
valve is controlled to open. The scan tool will display a
higher percentage when the intake throttle solenoid
valve is controlled to close.
Desired Intake Throttle Position
This parameter displays intake throttle position desired
by the ECM based on current driving conditions. This
can be compared to the actual intake throttle position to
determine sensor accuracy or intake throttle control
problems.
Intake Throttle Position
This parameter displays the intake throttle valve
position calculated by the ECM using the signal from
intake throttle position sensor. The scan tool will display
a low percentage when the intake throttle valve is
closed, and a high percentage when the intake throttle
valve is opened. Note that the intake throttle position
indicates over 100% if the solenoid is commanded
OFF.
Intake Throttle Position Sensor
This parameter displays the voltage signal sent to the
ECM from the intake throttle position sensor. Intake
throttle position sensor is a range of value indicating a
low voltage when the intake throttle valve is closed to a
high voltage when the intake throttle valve is opened.
Desired Injection Quantity
This parameter displays a total injection quantity (main
injection quantity + pre injection quantity) desired by
the ECM based on current driving conditions.
Main Injection Quantity
This parameter displays a main injection quantity
desired by the ECM based on current driving
conditions. Main Injection Timing
This parameter displays a main injection timing desired
by the ECM based on current driving conditions.
Main Injection On Time
This parameter displays the time the ECM turns ON the
fuel injectors. The scan tool will display a higher value
with a longer pulse width, or a lower value with a
shorter pulse width.
Pre Injection Quantity
This parameter displays a pilot injection quantity
desired by the ECM based on current driving
conditions.
Pre Injection Interval
This parameter displays a injection interval between
end of pilot injection and start of main injection desired
by the ECM based on current driving condition.
Fuel Compensation Cyl. 1 to 4
This parameter displays the adjustment of fuel volume
for each cylinder at low engine speed area as
calculated by the ECM. The scan tool will display a
negative value if the fuel volume is lowered. The scan
tool will display a positive value if the fuel volume is
increased. If there is a cylinder that is excessively high
or low value, it may indicate faulty fuel injector, weak or
slightly seized cylinder or an incorrectly programmed
fuel injector ID code.
Cylinder Balancing Update
This parameter displays the state of the fuel
compensation for each cylinder. Enabled indicates the
adjustment of fuel volume for each cylinder is being
executed by the ECM when the engine is idle speed,
the engine coolant temperature sensor, the intake air
temperature sensor, barometric pressure sensor and
the vehicle speed sensor inputs are normal state.
Fuel Supply Pump Status
This parameter displays the learning state of the fuel
supply pump. Not Learn indicates initialized state that is
replaced to a new ECM or adjustment value is reset.
After engine is warm upped, leaning will start at idle
speed. Learning indicates learning state. Learned
indicates learning process is completed state.
Rail Pressure Feedback Mode
This parameter displays the state of the fuel rail
pressure feedback to the ECM. Wait Mode indicates
the ignition switch is turned ON position. Feedback
Mode indicates the engine is during crank or run.
Shutoff Mode indicates the ignition switch is turned
OFF position.
Engine Mode
This parameter displays the state of engine. Ignition On
indicates the ignition switch is turned ON position.
Cranking indicates the engine is during crank. Running
indicates the engine is run. Off indicates the ignition
switch is tuned OFF position.

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–71
F0: Diagnostic Trouble Code
The purpose of the “Diagnostic Trouble Codes” mode is
to display stored trouble code in the ECM.
When “Clear DTC Information” is selected, a “Clear
DTC Information”, warning screen appears.
This screen informs you that by cleaning DTC's “all
stored DTC information in the ECM will be erased”.
After clearing codes, confirm system operation by test
driving the vehicle.
Use the “DTC Information” mode to search for a specific
type of stored DTC information.
History
This selection will display only DTCs that are stored in
the ECM's history memory. It will not display Type B
DTCs that have not requested the MIL (“Check Engine Lamp”). It will display all type A and B DTCs that
requested the MIL and have failed within the last 40
warm-up cycles. In addition, it will display all type C and
D DTCs that have failed within the last 40 warm-up
cycles.
MIL SVC or Message Request
This selection will display only DTCs that are requesting
the MIL. Type C and Type D DTCs cannot be displayed
using the MIL. Type C and D DTCs cannot be displayed
using this option.
This selection will report type B DTCs only after the MIL
has been requested.
Last Test Failed
This selection will display only DTCs that have failed the
last time the test run. The last test may have run during
a previous ignition cycle of a type A or type B DTC is
displayed. For type C and type D DTCs, the last failure
must have occurred during the current ignition cycle to
appear as last test fail.
Test Failed Since Code Cleared
The selection will display all active and history DTCs
that have reported a test failure since the last time
DTCs were cleared. DTCs that last failed more that 40
warm-up cycles before this option is selected will not be
displayed.
No Run Since Code Cleared
This selection will display up to DTCs that have not run
since the DTCs were last cleared. Since any displayed
DTCs have not run, their condition (passing or failing) is
unknown.
Failed This Ignition
This selection will display all DTCs that have failed
during the present ignition cycle.
F1: Data Display
The purpose of the “Data Display” mode is to
continuously monitor data parameters.
The current actual values of all important sensors and
signals in the system are display through F1 mode.
See the “Typical Scan Data” section.
F2: Snapshot
“Snapshot” allows you to focus on making the condition
occur, rather than trying to view all of the data in
anticipation of the fault.
The snapshot will collect parameter information around
a trigger point that you select.
F3: Miscellaneous Test:
The purpose of “Miscellaneous Test” mode is to check
for correct operation of electronic system actuators.
F0: Diagnostic Trouble Code
F0: Read DTC Infor By Priority
F1: Clear DTC Information
F2: DTC Information
F0: History
F1: MIL SVS or Message Requested
F2: Last Test Failed
F3: Test Failed Since Code Cleared
F4: Not Run Since Code Cleared
F5: Failed This Ignition
F1: Data Display
F0: Engine Data
F1: O2 Sensor Data
F2: Snapshot
F3: Miscellaneous Test
F0: Lamps
F0: Malfunction Indicator Lamps
F1: Relays
F0: Fuel Pump Relay
F1: A/C Clutch Relay
F2: EVAP
F0: Purge Solenoid
F3: IAC System
F0: IAC Control
F1: IAC Reset
F4: Injector Balance Test

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Engine Management – V6 – Diagnostics Page 6C1-2–165

Step Action Yes
No
10 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does DTC P0850 fail this ignition cycle? Go to Step 2 Go to Step 11
11 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.43 DTC P1648
DTC Descriptor
This diagnostic procedure supports DTC P1648 – W rong Security Code Entered.
Circuit Description
Tech 2 is used to program the engine control module (ECM). Before any programming, a security code must be entered
into Tech 2. The ECM will check if the code entered is correct before continuing. If the security code is incorrect, DTC
P1648 sets.
Conditions for Running the DTC
Conditions for running the DTC are:
• The ignition is switched on.
• The ignition voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
An incorrect security code is entered into Tech 2 when attempting to program the ECM.
Action Taken When the DTC Sets
W hen the DTC sets, the malfunction indicator lamp (MIL) is not displayed.
Conditions for Clearing the DTC
The immobiliser security code is a Type ‘C’ DTC. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when a Type ‘C’ DTC sets and conditions for clearing Type ‘C’ DTCs.
Additional Information
• Refer to 6C1-1 Engine Management –V6 – General Information for details of the ECM operation.
• Refer to 6C1-3 Engine Management –V6 – Service Operations for details on resetting the ECM.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.

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Engine Management – V6 – Diagnostics Page 6C1-2–166

Test Description
The following numbers refer to the step numbers in the diagnostic table:
4 This step tests the ECM ground circuits and supply voltage.
DTC P1648 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Using Tech 2, select the DTC display function.
NOTE
Do not attempt to perform any Tech 2 function that
requires the ECM security code to be entered.
Does DTC P1648 fail this ignition cycle? Go to Step 4 Go to Step 3
3 Using Tech 2, attempt a programming function that requires the ECM
security code to be entered. Refer to 6C1-3 Engine Management –V6
– Service Operations for details on resetting the ECM.
Has the programming function been successfully performed? System OK Go to Step 4
4 1 Test all ECM ground circuits for a high resistance or an open
circuit fault condition. Refer to 8A Electrical - Body and Chassis
for information on electrical fault diagnosis.
2 Test the ECM ignition supply voltage circuit for a high resistance, open circuit or short to ground fault condition. Refer
to 8A Electrical - Body and Chassis for information on electrical
fault diagnosis.
Has any fault been found and rectified? Go to Step 6 Go to Step 5
5 Replace the ECM. Refer to 6C1-3 Engine Management –V6 – Service
Operations for details on replacing the ECM.
Has the repair been completed? Go to Step 6 —
6 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
Does DTC P1648 fail this ignition cycle? Go to Step 2 Go to Step 7
7 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, clear all DTCs and check the system for correct operation.
7.44 DTC P1668, P2500 or P2501
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P1668 – Generator L Terminal Circuit Malfunction
• DTC P2500 – Generator L Terminal Low Voltage
• DTC P2501 – Generator L Terminal High Voltage

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Engine Management – V6 – Diagnostics Page 6C1-2–240

Cruise Control Switch: This parameter displays the state of the cruise control on/off switch input to the control module.
Cruise Control Disengagement Reason: The parameter displays which of a possible 28 causes for the cruise control
to disengage.
CC Disengagement 1 – 8 History (Cruise Control): The parameter displays the last 8 cruise control disengages in
order from 1 to 8, with 8 being the most recent. There are about 28 possible causes for the cruise control to disengage.
Cruise Resume/Acceleration Switch: This parameter displays the state of the cruise control resume/accel switch
position input to the ECM.
Cruise Set / Coast Switch: This parameter displays the state of the cruise controls set/decel. switch position input to
the ECM.
Cycles of Misfire: This parameter displays the number of misfire tests during 200 engine revolutions.
Cylinder 1 – 6 Injector Circuit Status: This parameter displays the state of the fuel injector control circuit. The
parameter displays ‘Fault’ if the fuel injector control circuit is open, shorted to ground, or shorted to voltage. This
parameter displays ‘Undefined Status’ until the control circuit has been commanded ‘On’.
Dec. Fuel Cutoff (Deceleration): This parameter displays the status of the ECM operating mode, used to turn off the
fuel injectors and the evaporative emission (EVAP) canister purge valve during certain deceleration conditions.
Desired Engine Idle Speed: This parameter displays the desired engine idle speed as commanded by the ECM.
Desired Throttle Position: This parameter displays the desired throttle position (TP) angle commanded by the ECM.
Distance Since DTC Cleared: This parameter displays the distance (km) travelled since any diagnostic trouble code
(DTC) has been cleared from the ECM memory.
DTC Set This Ignition: This parameter displays Yes if a DTC set on the current ignition cycle.
ECM Immobilized: This parameter displays ‘Yes’ when an internal control module reset occurs. Tech 2 will display ‘No’
under normal operating conditions.
Electronic Throttle Control Learn Counter: W hen the ECM performs a throttle body relearn procedure, the throttle
plate is commanded to move from the rest position (7% open) to full closed (0%), then to around 10% open.
At the start of this procedure, the Tech 2 ‘TAC Learn Counter’ parameter should display 0, then count up to 11 after the
procedure is completed. If the counter did not start at 0 or if the counter did not end at 11, a fault has occurred and a
DTC should set.
Engine Control Ignition Relay: This parameter displays the state of the control circuit for control module power relay
as commanded by the ECM.
Engine Control Ignition Relay Feedback: This parameter displays the voltage available at the engine control ignition
relay pin of the control module.
Engine Load: This parameter displays the calculated engine load in percent based on inputs to the control module from
various engine sensors.
Engine Oil Life Remaining: This parameter displays the percentage of engine oil life remaining. The controller
calculates the engine oil life by monitoring engine load, collant temperature and engine speed.
Engine Oil Pressure: This parameter displays the oil pressure in kPa from the ECM, developed from the engine oil
pressure (EOP) sensor input.
Engine Oil Pressure Sensor: This parameter displays ‘High’ if the engine oil pressure is within the correct range. If the
ECM detects that the engine oil pressure is not within the correct range, Tech 2 will display ‘Low’.
Engine Runtime: This parameter displays the time elapsed since the engine was started.
Engine Speed: This parameter displays the speed of the engine crankshaft rotation from information received from the
CKP sensor. If there is a CKP sensor DTC, the ECM calculates the engine speed from one of the camshaft position
(CMP) sensors.
EVAP Purge Solenoid (Evaporative Emission): This parameter displays the on-time or duty cycle of the EVAP
canister purge solenoid commanded by the ECM. Zero percent indicates no purge. One hundred percent indicates full
purge.
EVAP Purge Solenoid Valve Circuit Status (Evaporative Emission): This parameter displays the state of the EVAP
purge solenoid control circuit. The parameter displays ‘Fault’ if the EVAP purge solenoid control circuit is open, shorted
to ground, or shorted to voltage. The parameter displays ‘Undefined Status’ until the circuit has been established as
‘OK’.
Cooling Fan Relay: This parameter displays the control module commanded state of the fan relay control circuit.

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Engine Management – V6 – Diagnostics Page 6C1-2–246

NOTE
After an ECU reset, the ignition switch must be
turned Off for at least 10 seconds and then
turned On for at least one minute, before
attempting communication between Tech 2 and
the ECU.
Preconditions: The four digit security code must be entered into Tech 2 and the theft deterrent system
must be disarmed and the ignition switched ‘On’ with a programmed remote coded key.
F2: Fuel Trim Reset : This function resets the fuel trim data values learned by the ECM.
F3: Throttle Body Relearn : In this mode, Tech 2 commands the throttle plate from its rest position to full closed
then to about 10% open. This procedure takes approximately 6 – 8 seconds. At the start of this procedure,
the Tech 2, ‘Electronic Throttle Control Learn Counter’ parameter should display ‘0’ then count up to 11, after
the procedure is completed. If the counter does not start at ‘0’, nor display a count of ‘11’ at the conclusion of
the procedure, a fault has occurred and a DTC will set.


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