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6E-136 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
5Ask 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 7
—
61. Test the engine coolant temperature (ECT)
sensor at various temperature levels to
evaluate the possibility of a skewed sensor.
2. Replace the ECT sensor as necessary.
Did you find and correct the condition? —
Go to Step 7 Go to Diagnostic
Aids
7 1. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine and wait until engine is fully warm upped while observing the Coolant
Temperature parameter with a scan tool.
Does the scan tool indicate more than the specified
value? 11 0
°C (230 °F)
Go to Step 2 Go to Step 8
8 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No
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ISUZU KB P190 2007
Page 1754 of 6020

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-137
DTC P0219 (Flash Code 543)
Circuit Description
The crankshaft position (CKP) sensor is located on the
left-hand of the cylinder block rear and it is behind the
starter motor. The ECM calculates the engine speed
and exact position of the crankshaft based on the
signal pulse from the CKP sensor. If the ECM detects
an engine overrun condition, this DTC will set.
Condition for Setting the DTC • The ECM detects that the engine speed is more than 4900 RPM (4JK1 standard output) or 4700
RPM (4JK1 high output and 4JJ1).
Action Taken When the DTC Sets • The ECM illuminates the SVS lamp when the diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (Euro 4 Specification)
• The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
(Except Euro 4 Specification)
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
• The ECM inhibits cruise control. • The ECM stops engine running when the vehicle
speed is lower than 5 km/h (3 MPH) for 5 seconds.
The engine will run after the key is cycled when the
ignition has been tuned OFF for longer than 10
seconds.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the SVS Lamp/ DTC - Type C. (Euro 4
Specification)
• Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A. (Except Euro 4
Specification)
Diagnostic Aids • Make sure the CKP sensor is tight and the teeth are not damaged.
• Electromagnetic interference in the CKP sensor circuits may set this DTC.
• The Total Engine Overspeed Events parameter on scan tool indicates number of overrun events.
Notice: • This DTC is caused by an engine overspeed condition, which was most likely caused by driver
error (i.e. downshifting a manual transmission on a
steep grade). Excessive engine overspeed may
damage internal engine components.
Circuit/ System Testing DTC P0219
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 Important:
If DTC P0335 or P0336 is set, diagnose
that DTC first.
1. Install a scan tool.
2. Start the engine.
3. Observe the Engine Speed parameter with a scan tool.
4. Accelerate the engine as necessary.
Does the Engine Speed parameter ever exceed the
specified value? 5000 RPM
Go to Step 4 Go to Step 3
3 Ask the driver if overrun is caused by gear slip-out,
shift error, down-slope driving, etc. If engine
overrun has experienced, the engine must be
inspected and repaired as necessary.
Did you complete the action? —
Go to Step 6
—
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ISUZU KB P190 2007
Page 1755 of 6020

6E-138 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
41. Inspect the CKP sensor and sensor rotor for
the following conditions:
• Physical damage of sensor
• Loose or improper installation of sensor
• Excessive air gap
• Foreign material passing between sensor and sensor rotor
• Physical damage of sensor rotor
• Loose or improper installation of sensor rotor
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 6 Go to Step 5
5 Replace the CKP sensor. Refer to CKP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 5
—
61. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Accelerate the engine between idle and W.O.T. (accelerator pedal full travel) many
times while observing the Engine Speed
parameter with a scan tool.
Does the Engine Speed parameter ever exceed the
specified value? 5000 RPM
Go to Step 4 Go to Step 7
7 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No
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ISUZU KB P190 2007
Page 1756 of 6020

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-139
DTC P0231 or P0232 (Flash Code 69)
Circuit Description
The ECM controls the fuel pump relay which supplies
power to the fuel pump in the fuel tank. The ECM
commands the fuel pump relay ON for a certain length
of time at ignition switch is ON with the engine OFF.
During the engine running it is continuously
commanded ON. If the ECM detects an improper
voltage level on the relay control circuit, DTC P0231 or
P0232 will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects a low voltage condition on the fuel pump relay control circuit for longer than 3
second when the relay is commanded OFF. (DTC
P0231)
• The ECM detects a high voltage condition on the fuel pump relay control circuit for longer than 3
second when the relay is commanded ON. (DTC
P0232)
Action Taken When the DTC Sets • The ECM illuminates the SVS lamp when the diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (Euro 4 Specification) • The ECM illuminates the MIL when the diagnostic
runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
(Except Euro 4 Specification)
• The ECM limits fuel injection quantity.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the SVS Lamp/ DTC - Type C. (Euro 4
Specification)
• Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A. (Except Euro 4
Specification)
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Notice: • The fuel pump relay is commanded ON for 12 seconds at ignition switch is ON with the engine
OFF.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0231
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 a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition for 20 seconds while observing the DTC Information with a scan
tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition.
2. Replace the fuel pump relay with the head light relay or replace with a known good relay.
3. Turn ON the ignition for 20 seconds while observing the DTC Information with a scan
tool.
Does the DTC fail this ignition? —
Go to Step 4 Go to Step 7
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ISUZU KB P190 2007
Page 1757 of 6020

6E-140 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
41. Turn OFF the ignition.
2. Remove the fuel pump relay.
3. Probe the ignition voltage feed circuit of the relay coil side (pin 3 of X-13) with a test lamp
that is connected a known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 5 Go to Step 6
5 1. Test the control circuit between the ECM (pin
54 of C-58) and the relay (pin 5 of X-13) for
the following conditions:
• An open circuit
• A short to ground
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 8
6 Repair the open circuit or high resistance between
the ECM main relay (pin 1 of X-12) and the fuel
pump relay (pin 3 of X-13).
Did you complete the repair? —
Go to Step 11
—
71. Remove the fuel pump relay.
2. Inspect for an intermittent and for a poor connection on each relay terminal.
3. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
8 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
ECM (pin 54 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
9 Replace the fuel pump relay.
Did you complete the replacement? —
Go to Step 11
—
10Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 11
—
111. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Turn ON the ignition for 20 seconds while observing the DTC Information with a scan
tool.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 12
12 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No
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ISUZU KB P190 2007
Page 1758 of 6020

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-141
Circuit/ System Testing DTC P0232
StepAction 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 a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition.
2. Replace the fuel pump relay with the head light relay or replace with a known good relay.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail? —
Go to Step 4 Go to Step 5
4 1. Test the control circuit between the ECM (pin
54 of C-58) and the relay (pin 5 of X-13) for a
short to battery or ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 7 Go to Step 6
5 Replace the fuel pump relay.
Did you complete the replacement? —
Go to Step 7
—
6Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 7
—
71. Reconnect all previously disconnected relay
or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 8
8 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
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ISUZU KB P190 2007
Page 1759 of 6020

6E-142 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0234 (Flash Code 42)
Circuit Description
The boost pressure sensor is located in the air
induction tubing. The sensor is a transducer that varies
voltage according to changes in the air pressure inside
the air tubing. The ECM monitors the boost pressure
sensor signal for abnormal values. If the ECM detects
that the sensor signal is excessively high, this DTC will
set. This indicates excessive high boost pressure.
Condition for Running the DTC • DTCs P0045, P0107 and P0108 are not set.
• The ignition switch is ON.
• The engine is running.
Condition for Setting the DTC • The ECM detects that the actual boost pressure is more than 20 kPa (3 psi) over the desired boost
pressure under certain conditions for longer than
10 seconds.
Action Taken When the DTC Sets • The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection. • The ECM inhibits cruise control.
Diagnostic Aids • An open circuit or high resistance in the boost pressure low reference circuit may set this DTC.
• Misrouted vacuum hoses may set this DTC.
• Check the turbocharger nozzle control actuator for a sticking. Refer to Turbocharger in the Engine
Mechanical section.
• Use a scan tool to verify the integrity of the boost pressure sensor signal. Compare the Boost
Pressure to the Desired Boost Pressure under all
load conditions for an excessively high value.
• The fuel with which gasoline was mixed may set this DTC.
Test Description
The numbers below refer to the step number on the
Circuit/ System Testing.
3. A skewed boost pressure sensor value (shifted to a
higher pressure) can set this DTC. The Boost Pressure
on the scan tool should read near Barometric Pressure
(BARO) with the key ON and engine OFF.
4. A skewed BARO sensor value (shifted to a lower
pressure) may indicate a wrong boost pressure. The
BARO on the scan tool should read near surrounding
barometric pressure.
Schematic Reference: Vacuum Hose Routing
Diagram and Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0234
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 a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Is DTC P0045, P0107, P0108, P0638, P1196,
P1197, P1198, P2227, P2228 or P2229 also set? —
Go to Applicable DTC Go to Step 3
3 1. Turn ON the ignition, with the engine OFF.
2. Observe the Boost Pressure and Barometric Pressure (BARO) with a scan tool.
Does the scan tool indicate that the difference
between the Boost Pressure and BARO is more
than the specified value? 10 kPa (1.5
psi)
Go to Step 4 Go to Step 5
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ISUZU KB P190 2007
Page 1760 of 6020

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-143
4Compare the BARO value to the range specified in
the altitude vs. barometric pressure table. Refer to
Altitude vs Barometric Pressure.
Is the BARO parameter within the range specified? —
Go to Step 6 Go to Step 7
5 1. Inspect the following for possible causes of
high boost pressure.
• Misrouted turbocharger nozzle control actuator vacuum hoses
• Turbocharger nozzle control actuator or solenoid valve for a stuck condition.
Refer to Turbocharger Control System
Check in this section.
• Intake throttle valve sticking. Perform the Intake Throttle Solenoid Control with a
scan tool
• Oil in the air induction tubing causing an incorrect boost pressure sensor signal.
When there is adhesion of oil inside of
the tubing, intercooler or turbocharger it
needs to be wiped off.
2. Repair or replace as necessary.
Did you find and correction the condition? —
Go to Step 10 Go to Diagnostic
Aids
6 1. Turn OFF the ignition.
2. Disconnect the boost pressure sensor harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
boost pressure sensor (pin 2 of E-107).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for a poor connection and corrosion at the harness
connector of the ECM (pin 23 of E-90).
6. Test for high resistance of the low reference circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 10 Go to Step 8
7 1. Turn OFF the ignition.
2. Disconnect the BARO sensor harness connector.
3. Inspect for an intermittent and for poor connections at the harness connector of the
BARO sensor (pins 2 and 3 of E-40).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 18 and 19 of E-
90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 10 Go to Step 9
Step
Action Value(s)Yes No
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ISUZU KB P190 2007