2007 ISUZU KB P190 Harness

Engine Control System (4JH1) 6E-113
Step Action Value(s) Yes No
15 1. Reconnect all previously disconnected fuse 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. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 3 Go to Step 16
16 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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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-115
Step Action Value(s) Yes No
3 1. Turn OFF the ignition.
2. Inspect for the following conditions: • Vacuum hoses are damaged or kinked.
• Misrouted vacuum hoses.
• A turbocharger solenoid valve is damaged.
• A vacuum pump is damaged.
• A vacuum regulating valve is damaged.
• A turbocharger wastegate valve is
damaged.
• Contaminated, skewed or slow vacuum
pressure sensor.
3. Repair or replace as necessary.
Did you find and correct the condition? 

Go to Step 15 Go to Step 4
4 1. Turn ON the ignition, with the engine OFF. 2. Observe the Vacuum Pressure Sensor and Barometric Pressure (BARO) with the scan tool.
Does the scan tool indicate that the difference
between the Vacuum Pressure Sensor and doubled
BARO is less than the specified value? 10 hPa

Go to Step 7 Go to Step 5
5 1. Observe the BARO parameter with the scan tool.2. Compare 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 14
6 1. Turn OFF the ignition. 2. Disconnect the vacuum pressure sensor harness connector.
3. Inspect for an intermittent and for a poor connection at the vacuum pressure sensor
harness connector (pin 2 of C-124 connector).
4. Disconnect the engine control module (ECM) harness connector.
5. Inspect for an intermittent, for a poor connection and corrosion on vacuum pressure sensor circuit
at the harness connector of the ECM (pin 93 of
C-57 connector).
6. Test for high resistance on vacuum pressure sensor low reference circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 15 Go to Step 10
7 1. Turn OFF the ignition. 2. Disconnect the vacuum hose from the turbocharger wastegate valve that is connected
to the vacuum pressure sensor and the
turbocharger solenoid valve.
3. Start the engine and accelerate the engine as necessary.
Is there boost pressure leak from the turbocharger
wastegate valve port? 

Go to Step 13 Go to Step 8

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ISUZU KB P190 2007

6E-116 Engine Control System (4JH1)
Step Action Value(s) Yes No
8 1. Turn OFF the ignition.
2. Reconnect the vacuum hose to the turbocharger wastegate valve.
3. Disconnect the vacuum hose from the turbocharger solenoid valve that is connected to
the vacuum regulating valve “Z” port.
4. Connect a hand-held vacuum pump (5-8840- 0279-0/J-23738-A) to the disconnected vacuum
hose.
5. Start the engine and let engine idle.
Does the hand-held vacuum pump indicate more
than 23 cmHg (9 inHg)? 

Go to Step 9 Go to Step 12
9 1. Turn OFF the ignition. 2. Disconnect the hand-held vacuum pump from the vacuum hose.
3. Reconnect the vacuum hose to the turbocharger solenoid valve.
4. Disconnect the vacuum hose from the vacuum pressure sensor that is connected to the
turbocharger solenoid valve and the turbocharger
wastegate valve.
5. Connect a hand-held vacuum pump (5-8840- 0279-0/J-23738-A) to the disconnected vacuum
hose.
6. Disconnect the vacuum pressure sensor harness connector in order to active turbocharger
solenoid valve.
7 Start the engine and let engine idle.
Does the needle of hand-held vacuum pump shake
between 0 and 20 cmHg (8 inHg)? 

Go to Step 10 Go to Step 11
10 Replace the vacuum pressure sensor. Refer to Vacuum Pressure Sensor Replacement in this
section.
Did you complete the replacement? 

Go to Step 15 
11 Replace the turbocharger solenoid valve. Refer to
Turbocharger Solenoid Valve Replacement in this
section.
Did you complete the replacement? 

Go to Step 15 
12 Replace the vacuum regulating valve.
Did you compete the replacement? 

Go to Step 15 
13 Replace the turbocharger wastegate valve. Refer to
Turbocharger in Engine Mechanical section.
Did you complete the replacement? 

Go to Step 15 
14 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 15 
15 1. Reconnect all previously disconnected hoses 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. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 16

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ISUZU KB P190 2007

6E-120 Engine Control System (4JH1)
Step Action Value(s) Yes No
7 1. Turn OFF the ignition.
2. Disconnect the hand-held vacuum pump from the vacuum hose.
3. Connect the hand-held vacuum pump to the vacuum port of EGR valve.
4. Start the engine and let engine idle.
5. Apply vacuum pressure to the EGR valve while observing the MAF sensor parameter.
Does the MAF Sensor parameter decrease by at
least 200 mg/strk when the vacuum pressure is
applied? 

Go to Diagnostic Aids Go to Step 8
8 1. Turn OFF the ignition. 2. Disconnect the MAF sensor harness connector.
3. Inspect for an intermittent, for a poor connection and corrosion at the harness connector of the
MAF sensor (pin 3 of C-116 connector).
4. Disconnect the engine control module (ECM) harness connector.
5. Inspect for an intermittent, for a poor connection and corrosion on each MAF sensor circuit at the
harness connector of the ECM (pin 92 of C-57
connector).
6. Test for high resistance on each MAF sensor circuit.
7. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 11 Go to Step 9
9 Replace the EGR valve. Refer to EGR Valve Replacement in engine mechanical section.
Did you complete the replacement? 

Go to Step 11 
10 Replace the EGR solenoid valve. Refer to EGR
Solenoid Valve Replacement in this section.
Did you complete the replacement? 

Go to Step 11 
11 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 warm up (allow engine coolant temperature to reach at least 60°C
[140°F]) while observing the MAF Sensor
parameter with the scan tool.
Does the MAF Sensor parameter follow the Desired
MAF parameter within 50 mg/strk? 

Go to Step 12 Go to Step 2
12 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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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-121
DTC P0243 (Symptom Code 8) (Flash Code 64)
Circuit Description
The engine control module (ECM) controls the
turbocharger wastegate valve based on the barometric
pressure in order to reduce turbocharger spinning
speeds at high altitude area. The ECM controls the
turbocharger wastegate valve diaphragm by acting the
regulated vacuum pressure via controlling the solenoid
valve. The vacuum pressure sensor monitors the
regulated vacuum pressure to the turbocharge
r
wastegate valve. The ECM calculates desired vacuum
pressure and it compares the calculated desired
vacuum pressure to the actual value to determine the
solenoid valve position. W hen the actual vacuum
pressure is higher than the desired value, the solenoid
valve is closed to decrease the vacuum pressure. If the
ECM detects that a short to battery or ignition voltage
on the turbocharger solenoid valve control circuit, this
DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the high voltage condition
on the turbocharger solenoid valve control circuit
for longer than 3 seconds when the solenoid valve
is commanded ON.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
• The ECM limits fuel injection quantity.
• The ECM uses a turbocharger solenoid valve
control substitution of 32%.
• The ECM uses an EGR solenoid valve control
substitution of 10%.
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.
Test Description
The number below refers to the step number on the
diagnostic table.
3. If the control circuit of the turbocharger solenoid valve
between the ECM and the solenoid valve is normal, the
control circuit voltage low DTC P0243 (Symptom Code
4) will set.

DTC P0243 (Symptom Code 8) (Flash Code 64)
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. Start the engine.
4. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
Does the DTC fail this ignition? 

Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition. 2. Disconnect the turbocharger solenoid valve harness connector.
3. Start the engine.
4. Monitor the DTC Information with the scan tool.
Does the DTC P0243 (Symptom Code 4) set, but not
DTC P0243 (Symptom Code 8)? 

Go to Step 5 Go to Step 4

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ISUZU KB P190 2007

6E-122 Engine Control System (4JH1)
Step Action Value(s) Yes No
4 1. Test the control circuit between the engine
control module (ECM) (pin 96 of C-57 connector)
and the turbocharger solenoid valve (pin 2 of C-
123 connector) 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 turbocharger solenoid valve. Refer to Turbocharger Solenoid Valve Replacement in this
section.
Did you complete the replacement? 

Go to Step 7 
6 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 7 
7 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.
5. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 3 Go to Step 8
8 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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ISUZU KB P190 2007

6E-126 Engine Control System (4JH1)
Step Action Value(s) Yes No
4 1. Observe the Engine Speed parameter with the
scan tool.
2. Accelerate the engine between idle and W .O.T. (accelerator pedal full travel) many times while
observing the scan tool.
Does the Engine Speed parameter indicate correct
engine speed? 

Go to Step 9 Go to Step 5
5 1. Inspect the crankshaft position (CKP) sensor for tightness.
2. Remove the CKP sensor and check for damage, metal particles on magnet and for flywheel
circumference damage.
Did you find and correct the condition? 

Go to Step 10 Go to Step 6
6 1. Turn OFF the ignition.
2. Disconnect the CKP sensor harness connector.
3. Inspect for an intermittent, for poor connections and corrosion on the CKP sensor terminal (pins
1, 2 and 3 of E-9 connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition. 

Go to Step 10 Go to Step 7
7 1. Turn OFF the ignition. 2. Disconnect the fuel injection pump control unit (PCU) harness connector.
3. Inspect for an intermittent, for a poor connection and corrosion on the CKP sensor signal input at
the harness connector of the PCU (pin 8 of E-6
connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 10 Go to Step 8
8 1. Turn OFF the ignition. Disconnect the engine control module (ECM)
harness connector.
2. Inspect for an intermittent, for poor connections and corrosion on at the harness connector of the
ECM (pins 90, 91, 98 and 101 of C-57
connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 10 Go to Step 9
9 Important: The fuel injection pump must be timed to
the engine.
Replace the fuel injection pump. Refer to Fuel
Injection Pump Replacement in engine mechanical
section.
Did you complete the replacement? 

Go to Step 10 
10 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.
5. Accelerate the engine between idle and W .O.T. (accelerator pedal full travel) many times while
observing the DTC Information with the scan
tool.
Does the DTC fail this ignition? 

Go to Step 2 Go to Step 11
11 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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ISUZU KB P190 2007

6E-130 Engine Control System (4JH1)
DTC P0335 (Symptom Code B, D) (Flash Code 43)
Circuit Description
The crankshaft position (CKP) sensor is located on top
of the flywheel housing. There are 4 slits spaced 90 °
on the flywheel circumference. The CKP sensor is a
magnetic coil type sensor, which generates an AC
signal voltage based on the crankshaft rotational speed.
The engine control module (ECM) monitors both the
CKP sensor and injection pump camshaft position
(CMP) sensor signals to ensure they correlate with each
other.
If the ECM receives extra or missing CKP sensor signal
pulses, this DTC will set. (Symptom Code B)
If the ECM receives a certain amount of injection pump
CMP sensor signal pulses without a CKP sensor signal,
this DTC will set. (Symptom Code D)
Condition for Running the DTC
Symptom Code B • The ignition switch is ON.
• The engine speed is higher than 665 RPM
Symptom Code D • DTC P0335 (Symptom Code B) is not set.
• The ignition switch is ON.
• The fuel injection pump CMP sensor signal is
generated.
• The controller area network (CAN) communication
between the ECM and PCU is normal.
Condition for Setting the DTC
Symptom Code B • The ECM detects extra or missing CKP senso
r
signals while engine is running.
Symptom Code D
• The ECM detects that the CKP sensor signals are
not generated when doubled fuel injection pump
rotation speed is higher than 50 RPM.
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 engine speed substitution o
f
doubled fuel injection pump speed for engine
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.
• Ensure the sensor is tight and the flywheel
circumference is not damaged.

DTC P0335 (Symptom Code B, D) (Flash Code 43)
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. Start the engine (Note a slight start delay may be noticed).
4. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
Does the DTC fail this ignition? 

Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition. 2. Disconnect the crankshaft position sensor (CKP) harness connector.
3. Connect a DMM across the CKP sensor terminals (pins 1 and 2 of E-9 connector).
4. Measure the resistance across the CKP sensor.
Is the CKP sensor resistance within the specified
value? 870 – 930
Ω
Go to Step 4 Go to Step 20

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ISUZU KB P190 2007