coolant level ISUZU KB P190 2007 Workshop User Guide

Engine Control System (4JH1) 6E-93
DTC P0115 (Symptom Code 2) (Flash Code 14)
Circuit Description
The engine coolant temperature (ECT) sensor is
installed to the thermostat housing. The ECT sensor is
a variable resistor. The ECT sensor has a signal circuit
and a low reference circuit. The ECT sensor measures
the temperature of the engine coolant. The engine
control module (ECM) supplies 5 volts to the ECT signal
circuit and a ground for the ECT low reference circuit.
W hen the ECT sensor is cold, the sensor resistance is
high. W hen the engine coolant temperature increases,
the sensor resistance decreases. W ith high senso
r
resistance, the ECM detects a high voltage on the ECT
signal circuit. W ith lower sensor resistance, the ECM
detects a lower voltage on the ECT signal circuit. If the
ECM detects an excessively low ECT signal voltage,
this DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the ECT sensor signal
voltage is less than 0.3 volts for 3 seconds.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The ECM uses an ECT substitution of fuel
temperature for engine control.

•
The ECM uses an ECT substitution of 60 °C
(120 °F) for injection timing control.
• The ECM uses an ECT substitution -15 °C (5 °F) fo
r
glow control.
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.
•
After starting the engine, the ECT should rise
steadily to about 80°C – 85°C (176°F – 185°F)
then stabilize when the thermostat opens.
• Use the Temperature vs. Resistance table to test
the ECT sensor at various temperature levels to
evaluate the possibility of a skewed sensor.
A
skewed sensor could result in poor driveabilit
y
concerns.

DTC P0115 (Symptom Code 2) (Flash Code 14)
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 ON the ignition, with the engine OFF.
3. Observe the Engine Coolant Temperature (ECT) parameter with the scan tool.
Is the ECT parameter more than the specified value? 135°C (275°F)
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition. 2. Disconnect the ECT sensor harness connector.
3. Turn ON the ignition, with the engine OFF.
4. Observe the Coolant Temperature parameter with the scan tool.
Is the ECT parameter less than the specified value? -35°C (-31°F)
Go to Step 5 Go to Step 4
4 1. Test the signal circuit between the engine control module (ECM) (pin 89 of C-57 connector) and
the ECT sensor (pin 1 of E-41 connector) for the
following conditions: • A short to ground
• A short to the low reference circuit
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 8 Go to Step 6

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-204 Engine Control System (4JH1)
DTC P1173 (Symptom Code 3) (Flash Code 22)
Circuit Description
The engine coolant temperature (ECT) sensor is
installed to the thermostat housing. The ECT sensor is
a variable resistor. The ECT sensor has a signal circuit
and a low reference circuit. The ECT sensor measures
the temperature of the engine coolant. The engine
control module (ECM) supplies 5 volts to the ECT signal
circuit and a ground for the ECT low reference circuit.
W hen the ECT sensor is cold, the sensor resistance is
high. W hen the engine coolant temperature increases,
the sensor resistance decreases. W ith high senso
r
resistance, the ECM detects a high voltage on the ECT
signal circuit. W ith lower sensor resistance, the ECM
detects a lower voltage on the ECT signal circuit. If the
ECM detects an excessive high coolant temperature,
this DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects an excessive high coolant
temperature for longer than 30 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.
•
After starting the engine, the ECT should rise
steadily to about 80°C – 85°C (176°F – 185°F)
then stabilize when the thermostat opens.
• Use the Temperature vs. Resistance table to test
the ECT sensor at various temperature levels to
evaluate the possibility of a skewed sensor.
A
skewed sensor could result in poor driveabilit
y
concerns.
Notice: • This DTC is caused by an engine overheat
condition (i.e. low engine coolant level). Since this
DTC does not illuminate any lamps, clear the DTC
and ensure there are no signs of engine damage.
Excessive engine overheat may damage internal
engine components.

DTC P1173 (Symptom Code 3) (Flash Code 22)

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. Start the engine and wait until engine is fully warms upped.
4. Observe the Engine Coolant Temperature (ECT) parameter with the scan tool.
Is the ECT parameter more than the specified
value? 100°C (212°F)
Go to Step 4 Go to Step 3
3 Ask the driver if overheat is caused by low engine coolant level, etc.
If engine overheat has experienced, the engine must
be inspected and repaired as necessary.
Did you complete the action? 

Go to Step 6 
4 1. Test the ECT sensor at various temperature
levels to evaluate the possibility if a skewed
sensor.
2. Replace the ECT sensor as necessary.
Did you find and correct the condition? 

Go to Step 6 Go to Step 5

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-205
Step Action Value(s) Yes No
5 1. Test the engine cooling system for the following
condition. Refer to diagnosis of the engine
cooling system section for testing. • Engine coolant level
• Engine coolant leakage
• Cooling fan belt slippage
• Cooling fan clutch working
• Thermostat working
• W ater pump working
• Radiator clogging
2. Repair or replace as necessary.
Did you find and correct the condition? 

Go to Step 6 Go to Diagnostic
Aids
6 1. Reconnect all previously disconnected harness connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine and wait until engine is fully warms upped.
5. Observe the ECT parameter with the scan tool.
Is the ECT parameter more than the specified
value? 100°C (212°F)
Go to Step 4 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


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-266 Engine Control System (4JH1)
Lack of Power, Sluggishness, Sponginess
Checks Action
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 (A/T only).
• 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 engine control module (ECM) and fuel injection pump control unit (PCU)
grounds for being clean, tight, and in their proper locations.
• Inspect the scan tool Data List in this section.
• Inspect the Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool
Data List in this section.
• Use the scan tool to compare the Engine Coolant Temperature (ECT) with the Intake
Air Temperature (IAT) and Fuel Temperature (FT) 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 on the low reference circuit and signal circuit or for a
skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT sensor may
indicate a higher than normal intake air temperature if the ignition switch is being
ON. FT sensor is internal to the PCU and it is part of the fuel injection pump
assembly.
• Use the scan tool to compare the MAF Sensor parameter with the Desired MAF
parameter. Start the engine and warm up (allow engine coolant temperature to reach
at least 60°C [140°F]). The MAF Sensor parameter must follow the Desired MAF
parameter within 100 mg/strk. If not, inspect the air intake system, EGR system
components and contaminated, skewed or slow MAF sensor.
• Use the scan tool to observe the Accelerator Pedal Position Accelerator Pedal
Position. Accelerator Pedal Position parameter should change linearly from 0% to
100% according to the accelerator pedal operation.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-268 Engine Control System (4JH1)
Checks Action
Engine Mechanical Check Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression. Proper compression is more than 2100 kPa
(309 psi).
• Improper mechanical timing
• Improper valve gap
• Broken or weak valve springs
• W orn camshaft lobes
Additional Checks •
Inspect the generator output voltage. Repair if less than 9 volts or more than 16
volts.
• Inspect the EGR system operating correctly.
• Inspect the engine overheat condition. Refer to the Engine Cooling section.
• Inspect the A/C operation.
• Inspect the torque converter clutch (TCC) operation (A/T only).


Hesitation, Sag, Stumble
Checks Action
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 scan tool Data List in this section.
• Inspect the engine control module (ECM) and fuel injection pump control unit (PCU)
grounds for being clean, tight, and in their proper locations.
• Inspect the Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool
Data List in this section.
• Use the scan tool to compare the Engine Coolant Temperature (ECT) with the Intake
Air Temperature (IAT) and Fuel Temperature (FT) 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 on the low reference circuit and signal circuit or for a
skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT sensor may
indicate a higher than normal intake air temperature if the ignition switch is being ON.
FT sensor is internal to the PCU and it is part of the fuel injection pump assembly.
• Use the scan tool to compare the MAF Sensor parameter with the Desired MAF
parameter. Start the engine and warm up (allow engine coolant temperature to reach
at least 60°C [140°F]). The MAF Sensor parameter must follow the Desired MAF
parameter within 100 mg/strk. If not, inspect the air intake system, EGR system
components and contaminated, skewed or slow MAF sensor.
• Use the scan tool to observe the Accelerator Pedal Position Accelerator Pedal
Position. Accelerator Pedal Position parameter should change linearly from 0% to
100% according to the accelerator pedal operation.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-271
Checks Action
Engine Mechanical Checks Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression. Proper compression is more than 2100 kPa
(309 psi).
• Inspect for incorrect basic engine parts such as camshaft, cylinder head, pistons,
etc.
• Inspect for any excessive oil entering combustion chamber.
Additional Checks •
Inspect the EGR system operating correctly.
• Inspect other possible causes that can make similar noise such as loose component
parts, bracket, mount and weak clutch damper spring.


Poor Fuel Economy
Checks Action
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 (A/T only).
• 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.
• Suggest to the driver to read the Important Facts on Fuel Economy in the Owner
Manual.
• Inspect the odometer is correctly operated.
• Inspect the Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool
Data List in this section.
• Use the scan tool to compare the Engine Coolant Temperature (ECT) with the Intake
Air Temperature (IAT) and Fuel Temperature (FT) 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 on the low reference circuit and signal circuit or for a
skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT sensor may
indicate a higher than normal intake air temperature if the ignition switch is being ON.
FT sensor is internal to the PCU and it is part of the fuel injection pump assembly.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to the Fuel System section.
• Inspect the fuel type and quality.
• Check fuel leak.
Cooling System Checks Inspect the cooling system for the following conditions. Refer to the Cooling System
Section.
• Inspect the engine coolant level.
• Inspect the engine thermostat for always being open or for the wrong heat range.
• Inspect the engine cooling fan for always being ON.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-272 Engine Control System (4JH1)
Checks Action
Air Intake System Checks Inspect the air intake system for the following conditions.
• Inspect the air cleaner and air intake ducts for a restriction, holes, or leaks.
• Inspect for a restriction or leak in the intercooler.
• Inspect for a restriction in the turbocharger inlet duct.
• Inspect for a restriction or deposit in the intake throttle bore.
• Inspect for a restriction or leak in the intake manifold.
• Inspect for a restriction or damage at MAF sensor.
Exhaust System Checks Inspect the exhaust system for a possible restriction. Refer to the Exhaust System
section.
• Inspect for a restriction in the catalytic converter or exhaust pipes.
Engine Mechanical Checks Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression. Proper compression is more than 2100 kPa
(309 psi).


Excessive Smoke (Black Smoke)
Checks Action
DEFINITION:Black smoke under load, idle or start up hot or cold.
Preliminary Check •
Ensure the vehicle has an actual problem.
• Inspect the engine control module (ECM) and fuel injection pump control unit (PCU)
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 Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool
Data List in this section.
• Use the scan tool to compare the Engine Coolant Temperature (ECT) with the Intake
Air Temperature (IAT) and Fuel Temperature (FT) 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 on the low reference circuit and signal circuit or for a
skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT sensor may
indicate a higher than normal intake air temperature if the ignition switch is being ON.
FT sensor is internal to the PCU and it is part of the fuel injection pump assembly.
• Use the scan tool to compare the MAF Sensor parameter with the Desired MAF
parameter. Start the engine and warm up (allow engine coolant temperature to reach
at least 60°C [140°F]). The MAF Sensor parameter must follow the Desired MAF
parameter within 100 mg/strk. If not, inspect the air intake system, EGR system
components and contaminated, skewed or slow MAF sensor.
• Use the scan tool to observe the Accelerator Pedal Position Accelerator Pedal
Position. Accelerator Pedal Position indicating angle 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.
• Inspect the fuel injection nozzle(s) for proper splay condition or operating pressure.
Notice: Only first stage of operating pressure can be checked.
• Inspect the timing device operating correctly. Observe the Actual Injection Timing
parameter with the scan tool while running the engine. The Actual Injection Timing
parameter must follow the Desired Injection Timing within 2°CA on each engine
speed. Engine idle > around 2000 RPM> around 3000 RPM. If not, inspect the fuel
system restriction, air in the fuel or fuel injection pump operation.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-280 Engine Control System (4JH1)
EGR Solenid Valve Replacement
Removal Procedure 1. Disconenct the negative battery cable.
2. Disconnect a EGR solenoid valve harness connector.
3. Disconnect two hoses from the EGR solenoid valve.
4. Loosen two bolts and remove the EGR solenoid valve from the bracket.







Installation Procedure
1. Tighten the purge solenoid by tow bolts.
2. Connect a connector to the EGR solenoid valve.
3. Connect two hoses to the EGR solenoid valve.
4. Connect the negative battery cable.

Engine Coolant Temperature (ECT) Sensor
Replacement
1. Removal Procedure
2. Disconnect the negative battery cable.
3. Drain enough engine coolant so that the coolant level will be below the ECT sensor.
4. Disconnect connector from the ECT sensor.
5. Loosen and remove the ECT sensor from the thermostat housing.

Notice: Cool down the engine before above procedures
are carried out.









Installation Procedure
1.
Apply sealer to threads of screw at the ECT
sensor.
2. Tighten the ECT sensor with specified tightening torque.
Tightening Torque • Bolt: 13 N.m (1.3 kgf.m)
3. Connect a ECT sensor connector to the ECT sensor.
4. Fill the engine coolant.
5. Connect the negative battery cable.

Notice: Verify no engine coolant leaking from the
sensor threads after replacement.

Mass Air Flow (MAF) / Intake Air
Temperature (IAT) Sensor Replacement
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect a MAF & IAT sensor connector from the MAF & IAT sensor assembly.
3. Loosen the clips and remove the MAF & IAT sensor assembly from the intake duct housing.



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6B-6 ENGINE COOLING (4JK1/4JJ1)
Diagnosis
Engine Cooling Trouble
Condition Possible Cause Correction
Low Engine Coolant level Replenish
Thermo meter unit faulty Replace
Faulty thermostat Replace
Faulty Engine Coolant temperature
sensor Repair or replace
Clogged radiator
Clean or replace
Faulty radiator cap Replace
Low engine oil level or use of
improper engine oil Replenish or change oil
Clogged exhaust system
Clean exhaust system or replace
faulty parts
Faulty Throttle Position sensor Replace throttle valve assembly
Open or shorted Throttle Position
sensor circuit Repair or replace
Engine overheating
Damaged cylinder head gasket Replace
Engine overcooling Faulty thermostat Replace
Faulty thermostat Replace Engine slow to warm–up
Thermo unit faulty Replace


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE COOLING (4JK1/4JJ1) 6B-7
Draining and Refilling Cooling System
Before draining the cooling system, inspect the system
and perform any necessary service to ensure that it is
clean, does not leak and is in proper working order.
The engine coolant (EC) level should be between the
“MIN" and “MAX" lines of the reserve tank when the
engine is cold. If low, check for leakage and add EC up
to the “MAX" line.
There should not be any excessive deposit of rust o
r
scales around the radiator cap or radiator filler hole, and
the EC should also be free from oil.
Replace the EC if excessively dirty.

1. Remove the radiator skid plate.
2. Completely drain the cooling system by opening the drain plug at the bottom of the radiator.




RTW 56BSH000301
3. Remove the radiator cap.
WARNING:
To avoid the danger of being burned, do not
remove the cap while the engine and radiator are
still hot. Scalding fluid and steam can be blown out
under pressure.
4. Disconnect all hoses from the EC reserve tank.
Scrub and clean the inside of the reserve tank with soap and water. Flush it well with clean water,
then drain it. Install the reserve tank and hoses.

5. Refill the cooling system with the EC using a
solution that is at least 50 percent antifreeze.

Procedure for filling with coolant (in case of full change).
• Make sure that the engine is cool.
• Open radiator cap and pour coolant up to fille
r
neck.
• Pour coolant into reservoir tank up to “MAX" line.
• Tighten radiator cap and start the engine. Afte
r
idling for 2 to 3 minutes, stop the engine and
reopen the radiator cap. If the water level is lower,
replenish.
WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor o
r
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure when the coolant has
become cooler.
• After tightening the radiator cap, warm up the
engine at about 2000 rpm. Set heater adjustment
to the highest temperature position, and let the
coolant circulate also into heater water system.
• Check to see the thermostat has opened through
the needle position of the water thermometer,
conduct a 5–minute idling again and stop the
engine.
• W hen the engine has been cooled, check fille
r
neck for water level and replenish if required.
Should extreme shortage of coolant be found,
check the cooling system and reservoir tank hose
for leakage.
• Pour coolant into the reservoir tank up to “MAX"
line.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007