2007 ISUZU KB P190 ECO mode

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

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

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

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

6E-144 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
8Replace the boost pressure sensor. Refer to Boost
Pressure Sensor Replacement.
Did you complete the replacement? —
Go to Step 10
—
9Replace the BARO sensor. Refer to BARO Sensor
Replacement.
Did you complete the replacement? —
Go to Step 10
—
101. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Drive the vehicle that the Calculated Engine Load parameter reaches at least 50% for
longer than 10 seconds (such as acceleration
on ramp) while comparing the Boost Pressure
to the Desired Boost Pressure.
Does the Boost Pressure parameter follow within
the specified value? ±
20 kPa ( ±3
psi)
Go to Step 11 Go to Step 2
11 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

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-145
DTC P0299 (Flash Code 65)
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 low, this DTC will
set. This indicates excessive low boost pressure.
Condition for Running the DTC • DTCs P0045, P0087, P0088, P0089, P0091, P0092, P0093, P0101, P0102, P0103, P0107,
P0108, P0116, P0117, P0118, P0122, P0123,
P0192, P0193, P0401, P0403, P0404, P0405,
P0406, P0638, P0652, P0653, P0698, P0699,
P1064, P1065, P1093, P1404, P2100, P2101,
P2103, P2227, P2228 and P2229 are not set.
• The ignition switch is ON.
• The engine is running.
• The fuel injection quantity is higher than a predetermined value.
Condition for Setting the DTC • The ECM detects that the actual boost pressure is more than 40 kPa (6 psi) below 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 cruise control. Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • Induction air leakage can cause a low boost pressure condition. A whistling noise may be heard
if a component is allowing air to enter the induction
system.
• Check for cracked air tubing that may only open during certain engine movement conditions.
• 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 low value.
• Loss of vacuum pressure or vacuum pump problem sets this DTC.
Test Description
The numbers below refer to the step number on the
diagnostic table.
4. A skewed boost pressure sensor value (shifted to a
lower 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.
5. A skewed BARO sensor value (shifted to a higher
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 P0299
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, P2227, P2228 or
P2229 also set? —
Go to Applicable DTC Go to Step 3

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-147
61. Turn OFF the ignition.
2. Disconnect the boost pressure sensor harness connector.
3. Inspect for an intermittent and for poor connections at the harness connector of the
boost pressure sensor (pins 1 and 3 of E-107).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 20 and 21 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 8
7 1. Turn OFF the ignition.
2. Disconnect the BARO sensor harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
BARO sensor (pin 1 of E-40).
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 17 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 9
8 Replace the boost pressure sensor. Refer to Boost
Pressure Sensor Replacement.
Did you complete the replacement? —
Go to Step 10
—
9Replace the BARO sensor. Refer to BARO Sensor
Replacement.
Did you complete the replacement? —
Go to Step 10
—
101. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Drive the vehicle that the engine speed is more than 2000 RPM and the Calculated
Engine Load parameter reaches at least 50%
for longer than 10 seconds (such as
acceleration on ramp) while comparing the
Boost Pressure to the Desired Boost
Pressure.
Does the Boost Pressure parameter follow within
the specified value? ±
20 kPa ( ±3
psi)
Go to Step 11 Go to Step 2
11 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

6E-148 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0335 (Flash Code 15)
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 sensor rotor is fixed on the
crankshaft. There are 56 notches spaced 6 ° apart and
a 30 ° section that is open span. This open span portion
allows for the detection of top dead center (TDC). The
CKP sensor is a magnetic resistance element (MRE)
type sensor, which generates a square wave signal
pulse. The sensor has the following circuits.
• 5 volts reference circuit
• Low reference circuit
• CKP sensor signal circuit
The ECM monitors both CKP sensor and camshaft
position (CMP) sensor signal pulses to ensure they
correlate with each other. If the ECM receives a certain
amount of CMP sensor signal pulses without a CKP
sensor signal pulse, this DTC will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
• The CMP sensor signal pulse is detected.
Condition for Setting the DTC • The ECM detects that the CKP sensor signal pulses are not generated during engine rotations. 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.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Electromagnetic interference in the CKP sensor circuits may set this DTC.
• An intermittent CKP sensor signal pulse may set this DTC.
• Ensure the sensor is tight and the sensor rotor teeth are not damaged.
Notice: • If the CKP sensor signal pulse is lost while running, the engine will stop.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0335
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 (Note a slight start delay may be noticed).
4. Monitor the DTC Information with a scan tool.
Is DTC P0340, P0341, P0698 or P0699 also set? —
Go to Applicable DTC Go to Step 3
3 Observe the Cam/ Crank Sensor Signal
Synchronization Status parameter with a scan tool.
Does the scan tool indicate Synchronous? —
Go to Diagnostic
Aids Go to Step 4
4 1. Turn OFF the ignition.
2. Disconnect the crankshaft position (CKP) sensor harness connector.
3. Connect a DMM between the 5 volts reference circuit (pin 3 of E-52) and a known good
ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified value? 4.7 volts
Go to Step 5 Go to Step 9

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ISUZU KB P190 2007