2007 ISUZU KB P190 air condition

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-118 Engine Control System (4JH1)
DTC P0243 (Symptom Code 6) (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.
The mass air flow (MAF) sensor monitors boost
pressure by monitoring the amount of mass air flow. An
expected MAF amount should be detected while the
engine running. If the ECM detects the actual MAF
amount is higher than desired MAF amount, this DTC
will set. This indicates excessive high boost pressure
and turbocharger wastegate valve most likely did not
active.
Condition for Running the DTC
• The ignition switch is ON.
• The engine coolant temperature (ECT) is between
-50°C (-58 °F) and 150°C (302°F).
• The EGR solenoid valve control is OFF.
• The MAF sensor DTC P0100 is not set.
• The vacuum pressure sensor DTC P0105 is not
set.
• The intake air temperature (IAT) sensor DTC
P0110 is not set.
Condition for Setting the DTC
• The ECM detects that the MAF amount is 56
mg/strk higher than the desired MAF for 3
seconds. This indicates an excessive high boost
pressure.
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 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.
• Check the wastegate for a sticking or stuck
condition. Refer to W astegate Operation in the
Engine Mechanical section.
• Use the scan tool to verify the integrity of the MAF
sensor signal. Compare the sensor values unde
r
all load conditions for an excessively high value.
Use the scan tool data list values for nominal
sensor readings.
• The fuel with which gasoline was mixed may set
this DTC.
• A sticking or intermittently sticking the EGR valve
may set this DTC.
• Misrouted vacuum hoses may set this DTC.

DTC P0243 (Symptom Code 6) (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 and let idle for 30 seconds.
4. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
Is DTC P0105 (Symptom Code 1, 2, 7 or 9), P0243
(Symptom Code 3, 4, 5 or 8) or P0400 (Symptom
Code 3, 4, 5 or 8) set? 

Go to Applicable DTC Go to Step 3

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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-119
Step Action Value(s) Yes No
3 1. Inspect the following for possible causes of high
boost pressure. • W astegate valve for a stuck closed
condition. Refer to the Turbocharger in
Engine Mechanical section for diagnosis.
• Restricted intake or collapsed hose.
2. Repair the condition as necessary.
Did you find and correction the condition? 

Go to Step 11 Go to Step 4
4 1. Turn OFF the ignition for 30 seconds. 2. Start the engine and warm up (allow engine coolant temperature to reach at least 60°C
[140°F]).
3. Perform the EGR Solenoid Valve test with the scan tool.
4. Command the EGR Solenoid Valve ON and OFF with the scan tool while observing the Mass Air
Flow (MAF) Sensor parameter.
Does the MAF Sensor parameter decrease by at
least 200 mg/strk within 2 seconds when the EGR
Solenoid Valve is commanded ON? 

Go to Diagnostic Aids Go to Step 5
5 1. Turn OFF the ignition. 2. Inspect for the following conditions: • An EGR valve control vacuum hose is
damaged or kinked.
• EGR solenoid valve vacuum hoses are
damaged or kinked.
• EGR solenoid valve ventilation is damaged.
• An EGR valve is stuck close.
• Restricted or collapsed EGR passage
between the exhaust manifold and EGR
valve.
• Oil in the air tubing causing an incorrect
MAF sensor signal. W hen there is
adhesion of oil, inside of the tubing,
intercooler and turbocharger needs to be
wipe off.
• Contaminated or skewed MAF sensor.
3. Repair or replace as necessary.
Did you find and correct the condition? 

Go to Step 11 Go to Step 6
6 1. Turn OFF the ignition. 2. Disconnect the EGR valve control vacuum hose from the EGR valve.
3. Connect a hand-held vacuum pump (5-8840- 0279-0/J-23738-A) to the disconnected vacuum
hose.
4. Start the engine and let engine idle.
5. Perform the EGR Solenoid Valve test with the scan tool.
6. Command the EGR Solenoid Valve ON and OFF with the scan tool.
Does the hand-held vacuum pump indicate more
than 50 cmHg (20 inHg) when commanding the ON
and less than 10 cmHg (4 inHg) when commanding
OFF? 

Go to Step 7 Go to Step 10

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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

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

Engine Control System (4JH1) 6E-131
Step Action Value(s) Yes No
4 1. Connect a DMM across the CKP sensor
terminals (measure the sensor output voltage).
2. Place the DMM on the AC volt scale.
3. Start the engine.
4. Monitor the DMM while accelerating the engine between idle and W .O.T. (accelerator pedal full
travel).
Does the DMM indicate an AC voltage increase in
accordance with an engine speed increase (the
range of approximately 1.4 volts is indicated from
approximately 0.7 volts)? 

Go to Step 5 Go to Step 19
5 1. Turn ON the ignition, with the engine OFF. 2. Connect a test lamp between the low reference circuit of the CKP sensor harness (pin 1 of E-9
connector) and a known good ground.
Does the test lamp illuminate? 

Go to Step 11 Go to Step 6
6 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a test lamp between the low reference circuit of the CKP sensor harness (pin 1 of E-9
connector) and battery voltage.
Does the test lamp illuminate? 

Go to Step 7 Go to Step 12
7 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a test lamp between the shield ground circuit of the CKP sensor harness (pin 3 of E-9
connector) and a known good ground.
Does the test lamp illuminate? 

Go to Step 13 Go to Step 8
8 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a test lamp between the shield ground circuit of the CKP sensor harness (pin 1 of E-9
connector) and battery voltage.
Does the test lamp illuminate? 

Go to Step 9 Go to Step 14
9 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a test lamp between the signal circuit of the CKP sensor harness (pin 2 of E-9 connector)
and battery voltage.
Does the test lamp illuminate? 

Go to Step 15 Go to Step 10
10 1. Keep the ignition switch ON, with the engine OFF.
2. Connect a DMM between the signal circuit of the CKP sensor harness (pin 2 of E-9 connector) and
a known good ground.
Is the DMM voltage more than the specified value? 1 volt
Go to Step 16 Go to Step 17
11 Important: The ECM may be damaged if the sensor
low reference circuit is shorted to a voltage source.
1. Test the low reference circuit of the CKP sensor between the engine control module (ECM) (pin
98 of C-57 connector) and the CKP sensor (pin 1
of E-9 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 22 Go to Step 21

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ISUZU KB P190 2007

6E-132 Engine Control System (4JH1)
Step Action Value(s) Yes No
12 1. Test the low reference circuit of the CKP sensor
between the ECM (pin 98 of C-57 connector) and
the CKP sensor (pin 1 of E-9 connector) for an
open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 18
13 Important: The ECM may be damaged if the sensor
shield ground circuit is shorted to a voltage source.
1. Test the shield ground circuit of the CKP sensor between the ECM (pin 101 of C-57 connector)
and the CKP sensor (pin 3 of E-9 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 22 Go to Step 21
14 1. Test the shield ground circuit of the CKP sensor between the ECM (pin 101 of C-57 connector)
and the CKP sensor (pin 3 of E-9 connector) for
an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 18
15 1. Test the signal circuit of the CKP sensor between the ECM (pin 90 of C-57 connector) and the CKP
sensor (pin 2 of E-9 connector) for the following
conditions: • A short to ground
• A short to the low reference circuit
• A short to the shield ground
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 21
16 Important: The CKP sensor may be damaged if the
sensor signal circuit is shorted to a voltage source.
1. Test the signal circuit of the CKP sensor between the ECM (pin 90 of C-57 connector) and the CKP
sensor (pin 2 of E-9 connector) for the following
conditions:
• A short to battery or ignition voltage
• A short to any 5 volts reference
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 21
17 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the CKP
sensor (pins 1, 2 and 3 of E-9 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 20
18 1. Turn OFF the ignition. 2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for poor connections on the CKP sensor circuits at the
harness connector of the ECM (pins 90, 98 and
101 of C-57 connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 22 Go to Step 21

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ISUZU KB P190 2007