2007 ISUZU KB P190 check engine

Engine Management – V6 – Diagnostics Page 6C1-2–105

Circuit Description
The engine control module (ECM) uses information from the crankshaft position (CKP) sensor and the camshaft position
(CMP) sensor to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation
speed for each cylinder, the ECM is able to detect individual misfire events. A misfire rate that is high enough can cause
3-way catalytic converter damage. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for
catalytic converter damage are preset. DTCs P0301 – P0306 correspond to cylinders 1 to 6. If the ECM is able to
determine that a specific cylinder is misfiring, the DTC for that cylinder sets.
Conditions for Running the DTC
• DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, or P0338 are not set.
• The engine speed is between 400 – 7,000 rpm and steady.
• The delivered torque signal is more than 10 percent at idle with the transmission in neutral.
• The delivered torque signal is between 10 – 30 percent with the transmission in drive.
• The intake air temperature (IAT) is more than –30° C.
• The engine run time is more than 45 seconds.
• The fuel level is more than 12 percent.
• The torque management is not active.
• DTCs P0301, P0302, P0303, P0304, P0305, and P0306 run continuously when the above conditions exist for at
least 1,000 engine revolutions.
Conditions for Setting the DTC
• The ECM detects a crankshaft rotation speed variation indicating a single cylinder misfire rate sufficient to cause
emissions levels to exceed mandated standards.
• The condition exists for more than 4 seconds.
Action Taken When the DTC Sets
• The control module activates the MIL on the second ignition cycle that the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic
fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the
second consecutive ignition cycle, the control module records the operating conditions at the time of the failure.
The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
• The ECM turns OFF the malfunction indicator lamp (MIL) after four consecutive ignition cycles that the diagnostic
runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL and the DTC.
Additional Information
• A misfire DTC could be caused by an excessive vibration from sources other than the engine. Check for the
following possible sources:
− Tyre or wheel out of round or balance
− Variable thickness brake rotor or drum
− Drive shaft not balanced
− Certain rough road conditions

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Engine Management – V6 – Diagnostics Page 6C1-2–106

− Damaged accessory drive belt
• For an intermittent condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Since a fault condition in a wiring connector may trigger DTCs, always test the connectors related to this
diagnostic procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A
Electrical - Body and Chassis for information on electrical fault diagnosis.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
DTC P0301, P0302, P0303, P0304, P0305 or P0306 Diagnostic Table
Step Action Yes No
1
Has the Diagnostic System Check been completed? Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2
W ere you sent here from DTC P0300? Go to Step 3 Go to 7.16
DTC P0300 in this Section
3 1 Ignition OFF.
2 Remove the ignition coil of the misfiring cylinder, but leave the electrical connector connected. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
3 Inspect the ignition coil boot for the following conditions:
− Holes.
− Tears.
− Carbon tracking.
− Oil contamination or water intrusion.
Did you find a condition with the ignition coil boot? Go to Step 12 Go to Step 4
4 1 Remove the fuel pump fuse from the under-hood fuse and relay
centre.
2 Install the J 26792 Spark Tester to the ignition coil boot and a good ground.
3 Crank the engine while observing J 26792.
Does the spark tester spark and is the spark consistent? Go to Step 5 Go to Electronic
Ignition System Diagnosis
5 1 Ignition OFF.
2 Remove the spark plug from the cylinder that indicated a misfire.
3 Inspect the spark plug. Refer to 6C1-3 Engine Management – V6 – Service Operations.
Does the spark plug appear to be OK? Go to Step 9 Go to Step 6
6
Is the spark plug oil or coolant fouled? Inspect the spark
plugs. Go to 6C1-3 Engine
Management – V6 – Service Operations Go to Step 7
7 Is the spark plug gas fouled? Go to Step 10 Go to Step 9
8 Does the spark plug show any signs of being cracked, worn, or
incorrectly gap? Go to Step 11 Go to Step 9

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Engine Management – V6 – Diagnostics Page 6C1-2–109

Conditions for Clearing the DTC
DTC P0324 – Knock Sensor (KS) Module Performance is a Type B DTC. Refer to 1.4 Diagnostic Trouble Codes in
this Section, for action taken when a Type B DTC sets and conditions for clearing Type B DTC.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the knock sensor (KS) system
operation.
• The ECM turns off the KS signal circuits when performing the ECM internal KS circuitry tests. DTC P0324 sets if
there is a fault condition in the internal ECM KS circuitry. Therefore, the KS and the KS signal circuits are not
tested in DTC P0324 Diagnostic Table.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
Test Description
The following number refers to the step number in the diagnostic table:
3 A crankshaft sensor DTC may trigger DTC P0324.
DTC P0324 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Operate the vehicle within the conditions for running the DTC.
3 Using Tech 2, select the DTC display function.
Does DTC P0324 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 Are DTCs relating to the CKP Sensor Circuit also set? Refer to
7.20 DTC P0335, P0336, P0337 or P0338 in this Section Go to Step 4
4 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 5 —
5 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running DTC P0324.
Does DTC P0324 fail this ignition cycle? Go to Step 2 Go to Step 6
6 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–111

Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the knock sensor (KS) system
operation.
• Preconditions for running knock sensor circuit DTCs requires that DTC P0324 has ran and passed. Therefore, the
diagnostic table for the knock sensor circuit DTCs is developed with the assumption the ECM internal KS circuitry
is functioning correctly.
• Excessive engine mechanical noise or engine knocking condition may trigger knock sensor circuit DTCs.
• The knock sensor must be tightened correctly. Refer to 6C1-3 Engine Management – V6 – Service Operations.
• The mounting between the knock sensor and engine must be free of burrs, casting flash and foreign material.
• The knock sensor head must be clear from hoses, brackets and engine wiring.
• If the knock sensor lead is damaged in any way, the sensor must be replaced.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
3 Identifies engine mechanical fault conditions that may trigger knock sensor circuit DTCs.
4 Identifies KS fault conditions that may trigger knock sensor circuit DTCs.
DTC P0327, P0328, P0332 and P0333 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Operate the vehicle within the conditions for running the DTC.
3 Using Tech 2, select the DTC display function.
Does DTC P0327, P0328, P0332 or P0333 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 Check the engine for excessive mechanical engine noise or engine
knocking fault condition. Refer to 6A1 Engine Mechanical – V6.
W as any fault found and rectified? Go to Step 7 Go to Step 4
4 Inspect the appropriate KS for the following fault condition. Refer to
6C1-3 Engine Management – V6 – Service Operations.
• incorrect KS attaching bolt torque value,
• burrs, casting flash or foreign material between the knock
sensor and engine,
• hoses, brackets or engine wiring touching the KS, and
• damaged KS wiring harness.
• sensor wiring harness for conditions that may induce
electromagnetic interference. Refer to 5.2 Intermittent Fault
Conditions in this Section.
W as any fault found and rectified? Go to Step 7 Go to Step 5

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Engine Management – V6 – Diagnostics Page 6C1-2–112

Step Action Yes No
5 Test the appropriate KS signal circuit and low reference circuit for a
high resistance, open circuit, short to ground or short to voltage or
shorted together fault condition. Refer to 8A Electrical - Body and
Chassis for information on electrical fault diagnosis.
W as any fault found and rectified? Go to Step 7 Go to Step 6
6 Replace the faulty KS. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 7 —
7 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does any of the knock sensor circuit DTCs fail this ignition cycle? Go to Step 2 Go to Step 8
8 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.20 DTC P0335, P0336, P0337 or P0338
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0335 – Crankshaft Position Sensor Circuit Malfunction
• DTC P0336 – Crankshaft Position Sensor Signal Range / Performance
• DTC P0337 – Crankshaft Position Sensor Circuit Low Duty Cycle
• DTC P0338 – Crankshaft Position Sensor Circuit High Duty Cycle
Circuit Description
The ECM applies the ground to the crankshaft position (CKP) sensor low reference circuit.
The CKP sensor in conjunction with the 58X reluctor wheel generates an AC signal voltage. The amplitude and
frequency of the signal generated is proportional to the engine speed. The ECM uses this signal from the CKP sensor
signal circuit to determine the engine rpm
In addition, the CKP sensor sends a signal to the ECM when piston No. 1 and piston No. 4 are at the top dead centre
position. The ECM monitors both the CKP signal and the camshaft position (CMP) sensor signal to determine the
compression stroke of piston No. 1.
A CKP sensor DTC sets if the ECM detects a fault condition in the CKP sensor signal circuit.
Conditions for Running the DTC
DTC P0335
Runs continuously once the following conditions are met:
• The engine is cranking or running.
• The ECM detects greater than 8 CMP sensor pulses.
DTC P0336
Runs continuously once the following conditions are met:

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Engine Management – V6 – Diagnostics Page 6C1-2–114

• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
3 The ECM supplies 2.5 V to signal circuit of the CKP sensor circuit to reduce the electro-magnetic interference (EMI). If the voltage is not within range, this indicates there is an ECM or an ECM circuit fault condition.
4 The ECM supplies 2.5 V to low reference circuit of the CKP sensor circuit to reduce the electro-magnetic interference (EMI). If the voltage is not within range, this indicates there is an ECM or an ECM circuit fault
condition.
DTC P0335 to P0338 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Start the engine.
3 Increase the engine speed to 1000 rpm for 30 seconds.
4 Using Tech 2, select the DTC display function.
Does DTC P0335, P0336, P0337 or P0338 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Disconnect the CKP sensor connector.
2 Switch on the ignition with the engine not running.
3 Using a digital multimeter, measure the voltage between the signal circuit of the sensor connector and a good ground.
Does the multimeter display 2 – 3 V? Go to Step 4 Go to Step 7
4 Using a digital multimeter, measure the voltage between the CKP
sensor low reference circuit and a good ground.
Does the multimeter display 2 – 3 V? Go to Step 5 Go to Step 7
5 Using a digital multimeter, measure the resistance between the
ground shield circuit of the CKP sensor at the ECM connector and the
ECM housing.
Does the multimeter display 5 Ω? Go to Step 6 Go to Step 7
6 Perform the following CKP sensor inspection:
• Inspect the sensor wiring harness for conditions that may induce
electromagnetic interference. Refer to
5.2 Intermittent Fault Conditions in this Section.
• Inspect the sensor for incorrect sensor installation or incorrect
attaching bolt torque value. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
W as any fault found and rectified? Go to Step 11 Go to Step 9
7 Test the CKP sensor signal circuit and low reference circuit for a high
resistance, open circuit, short to ground, short to voltage or shorted
together fault condition. Refer to 8A Electrical - Body and Chassis for
information on electrical fault diagnosis.
W as any fault found and rectified? Go to Step 11 Go to Step 10

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Engine Management – V6 – Diagnostics Page 6C1-2–115

Step Action Yes No
8 Repair the open or high resistance fault condition in the CKP sensor
ground shield circuit. Refer to 8A Electrical - Body and Chassis for
information on electrical repair procedures.
W as the repair completed? Go to Step 11 —
9 Replace CKP sensor. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 11 —
10 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 11 —
11 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does any of the CKP sensor circuit DTCs fail this ignition cycle? Go to Step 2 Go to Step 12
12 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.21 DTC P0341, P0342 or P0343
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0341 – Intake Camshaft Position Sensor Range / Performance (Bank 1)
• DTC P0342 – Intake Camshaft Position Sensor Low Voltage (Bank 1)
• DTC P0343 – Intake Camshaft Position Sensor High Voltage (Bank 1)
Circuit Description
The ECM applies 5 V to the camshaft position (CMP) sensors through the 5 V reference and ground through the low
reference circuit.
The CMP sensor is a Hall effect switch. In conjunction with a 4X reluctor wheel, the CMP sensors provide a signal
voltage to the ECM. The ECM uses this signal voltage to determine the position of the camshafts.
The ECM compares the CMP signal voltage to the number of crankshaft revolutions. A CMP sensor DTC sets if the
ECM detects a fault condition in the CMP sensor circuits.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
DTC P0342
The ECM detects no pulses from the CMP sensor signal circuit and the CMP sensor signal voltage is low in correlation
with the number of crankshaft revolutions.

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Engine Management – V6 – Diagnostics Page 6C1-2–116

DTC P0341
The ECM detects a signal from the CMP sensor signal circuit and the sensor signal range is not within the
predetermined parameter or the when the CMP sensor does not correlate with the crankshaft position.
DTC P0343
The ECM detects no pulses from the CMP sensor signal circuit and the CMP sensor signal voltage is always high.
Conditions for Clearing the DTC
The CMP sensor circuit DTCs are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when Type B DTCs set and conditions for clearing Type B DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the CMP sensor operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
3 Tests the signal circuit of the CMP sensor. This circuit is pulled-up to about 5 V.
4 Measures the integrity of the CMP sensor low reference circuit. Removal of the ECM Fuse 29 enables the ECM to power down completely prior to the test procedure.
DTC P0341, P0342 or P0343 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Start the engine.
3 Increase the engine speed to 1000 rpm for 30 seconds.
4 Using Tech 2, select the DTC display function.
Does P0341, P0342, P0343 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Switch off the ignition.
2 Disconnect the appropriate CMP sensor wiring connector.
3 Switch on the ignition with the engine not running.
4 Using a digital multimeter, measure the voltage between the signal circuit of the appropriate CMP sensor and the ECM
housing.
Does the multimeter display 4.8 – 5.2 V? Go to Step 4 Go to Step 7

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