2007 ISUZU KB P190 service

6E-332 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
High Idle Speed
ChecksAction
Definition:
Engine idle speed is higher than normal in regardless of engine coolant temperature.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Inspect that the harness connectors are correctly connected.
• Use the scan tool to compare the engine speed and tachometer on the instrument panel (IP) cluster.
• Inspect the battery voltage. If the battery voltage is less than 11 volts, the ECM set the idle speed 50RPM higher than normal.
• Inspect the A/C operation.
• Inspect the fuel type and quality.
• Inspect the engine oil level.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure parameter at idle in Neutral. The Fuel Rail Pressure should always be within 27 to 33 MPa (3,900 to 4,800 psi) after warm up.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to the Fuel System section.
• Fuel injectors. Remove the injectors and visually inspect. (Injector tip(s) may be damaged)

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-333
Cuts Out
ChecksAction
Definition:
A constant jerking that follows the engine speed, usually more pronounced as the engine load increase. The exhaust has a
steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to cut-out.
Preliminary Check • Diagnostic System Check - Engine Controls.
• Inspect that the harness connectors are correctly connected.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Observe the Mass Air Flow (MAF) parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
• Crankshaft position (CKP) sensor is tight and the sensor rotor is not damaged.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to Fuel System Check Chart
and appropriate procedure in the Fuel System section.
• Air in the fuel system.
• Water contamination in the fuel.
• Fuel waxing or icing.
• Fuel filter indicator lamp is continuously or frequently turned ON with engine run.
• In-tank fuel pump operation. Refer to In-tank Fuel Pump System Check in this section.
• Fuel leak off from the fuel pressure limiter valve and fuel injectors.
• Fuel lines between the fuel tank and fuel supply pump for being crushed, kinked, tightness, cracks and plugged.
• Inside the fuel tank for any foreign material that may be getting drawn into the fuel line pickup causing a blocked condition.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Injector Force Drive with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Air Intake System Checks Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
Exhaust System Checks Inspect the exhaust system for a possible restriction. Refer to the Exhaust System
section.
Additional Checks • Electromagnetic interference (EMI) on the reference circuit can cause an engine
miss condition. The scan tool can usually detect EMI by monitoring the engine
speed. A sudden increase in speed with little change in actual engine speed change
indicates that EMI is present. If a problem exists, check routing of high voltage
components, such as fuel injector solenoid valve wiring, near the sensor circuits.

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ISUZU KB P190 2007

6E-334 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Surges
ChecksAction
Difinition:
The engine has a power variation under a steady throttle or cruise. The vehicle seems to speed up and slow down with no
change in the accelerator pedal.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Ensure the driver understands the A/C compressor operation.
• Use the scan tool in order to make sure the Vehicle Speed parameter reading matches the vehicle speedometer.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect that the harness connectors are correctly connected.
• Inspect the fuel type and quality.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Observe the Mass Air Flow (MAF) parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to Fuel System Check chart
and appropriate procedure in the Fuel System section.
• Air in the fuel system.
• Water contamination in the fuel.
• Fuel waxing or icing.
• Fuel filter indicator lamp is continuously or frequently turned ON with engine run.
• In-tank fuel pump operation. Refer to In-tank Fuel Pump System Check in this section.
• Fuel leak off from the fuel pressure limiter valve and fuel injectors.
• Fuel lines between the fuel tank and fuel supply pump for being crushed, kinked, tightness, cracks and plugged.
• A plugged fuel tank vent valve and hose.
• Inside the fuel tank for any foreign material that may be getting drawn into the fuel line pickup causing a blocked condition.
• Fuel supply pump operation.
Notice: The fuel supply pump must be timed to the engine and adjustment value must
be learned to the ECM.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Injector Force Drive with a scan tool.

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ISUZU KB P190 2007

6E-336 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Lack of Power, Sluggishness or Sponginess
ChecksAction
Definition:
The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator
pedal.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Compare the vehicle with a similar unit. Ensure the vehicle has an actual problem.
• Remove the air cleaner and check for dirt, or for air ducts being plugged or restricted. Replace as necessary.
• Have the tire sizes changed?
• Are excessively heavy loads being carried?
• Inspect for clutch slip.
• Inspect brake drag.
• Inspect for a proper transmission shift pattern and down shift operation.
• Inspect the fuel quality (cetane index).
• Inspect the engine oil level and quality.
• Use the scan tool in order to make sure the Vehicle Speed parameter reading matches the vehicle speedometer.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the MAF parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
• Observe the Barometric Pressure (BARO) parameter. The BARO parameter should indicate near surrounding barometric pressure. Refer to Altitude vs. Barometric
Pressure. (Standard output)
• Observe the Boost Pressure and BARO with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other. (High output)

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ISUZU KB P190 2007

6E-338 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Hesitation, Sag or Stumble
ChecksAction
Definition:
The vehicle has a momentary lack of response when pushing down on the accelerator. The condition can occur at any vehicle
speed. The condition is usually most severe when trying to make the vehicle move from a stop. If severe enough, the condition
may cause the engine to stall.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Compare the vehicle with a similar unit. Ensure the vehicle has an actual problem.
• Remove the air cleaner and check for dirt, or for air ducts being plugged or restricted. Replace as necessary.
• Inspect for a proper transmission shift pattern and down shift operation.
• Inspect the fuel quality (cetane index).
• Inspect the engine oil level and quality.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the MAF parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
• Observe the Barometric Pressure (BARO) parameter. The BARO parameter should indicate near surrounding barometric pressure. Refer to Altitude vs. Barometric
Pressure. (Standard output)
• Observe the Boost Pressure and BARO with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other. (High output)
• Crankshaft position (CKP) sensor is tight and the sensor rotor is not damaged.

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ISUZU KB P190 2007

6E-340 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Abnormal Combustion Noise
ChecksAction
Definition:
A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with the throttle
opening.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Ensure the vehicle has an actual problem.
• Inspect for smoke associated with the combustion noise.
• Inspect the fuel quality (cetane index).
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Crankshaft position (CKP) sensor is tight and the sensor rotor is not damaged.
Fuel System Checks • If excessive smoke is present, check for a stuck open fuel injector. Inspect for fuel
leakage into the combustion chamber.
• Inspect the fuel injectors. Remove the injectors and visually inspect.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Injector Force Drive with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Engine Mechanical Checks Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Poor cylinder compression.
• Incorrect basic engine parts such as camshaft, cylinder head, pistons, etc..
• Inspect for any excessive oil entering combustion chamber.
Additional Checks • Inspect other possible causes that can make similar noise such as loose component
parts, bracket, mount and weak clutch damper spring.

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-341
Poor Fuel Economy
ChecksAction
Definition:
Fuel economy, as measured by actual road tests and several tanks of fuel, is noticeably lower than expected. Also, the
economy is noticeably lower than it was on this vehicle at one time, as previously shown by actual road tests.
Preliminary Checks • Remove the air cleaner and check for dirt, or for air ducts being plugged or
restricted. Replace as necessary.
• Inspect the driving habits of the owner.
• Is the A/C ON full time, defroster mode ON?
• Are the tires at the correct pressure?
• Are the tire sizes changed?
• Are excessively heavy loads being carried?
• Is the acceleration too much, too often?
• Inspect for clutch slip.
• Inspect brake drag.
• Inspect dive belt tension.
• Inspect for a proper transmission shift pattern and down shift operation.
• Inspect the fuel quality (cetane index).
• Inspect the engine oil level and quality.
• Suggest to the owner to fill the fuel tank and recheck the fuel economy.
• Inspect the odometer is correctly operated.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to the Fuel System section.
• Fuel type and quality.
• Check fuel leak.
Cooling System Checks Inspect the cooling system for the following conditions. Refer to the Cooling System
Section.
• Engine coolant level.
• Engine thermostat for always being open or for the wrong heat range.
• Engine cooling fan for always being ON.

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-343
Excessive Smoke (Black Smoke)
ChecksAction
Definition:
Black smoke under load, idle or start up hot or cold.
Preliminary Check • Ensure the vehicle has an actual problem.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Remove the air cleaner and check for dirt, or for air ducts being plugged or restricted. Replace as necessary.
• Inspect the fuel quality (cetane index).
• Inspect the engine oil level and quality.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the MAF parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ±5 MPa ( ±725 psi) quick enough.
• Observe the Barometric Pressure (BARO) parameter. The BARO parameter should indicate near surrounding barometric pressure. Refer to Altitude vs. Barometric
Pressure. (Standard output)
• Observe the Boost Pressure and BARO with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other. (High output)
Fuel System Checks Inspect the fuel system for the following conditions. Refer to the Fuel System section.
• Fuel injectors. Remove the injectors and visually inspect.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Pilot Injection Control with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Air Intake System Checks Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
• A worn or damaged turbocharger turbine wheel, shaft or compressor wheel. Refer to turbocharger inspection in the Engine Mechanical section.
Exhaust System Checks Inspect the exhaust system for a possible restriction. Refer to the Exhaust System
section.

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ISUZU KB P190 2007