check engine ISUZU KB P190 2007 Workshop Repair Manual

Engine Management – V6 – Diagnostics Page 6C1-2–35

Checks Actions
Fuel System
• Check the fuel system for the following fault conditions. Refer to 6C Fuel System
– V6.
− restricted fuel filter,
− incorrect fuel pressure, and
− contaminated fuel.
• Check the operation of the fuel injectors. Refer to 6C1-3 Engine Management –
V6 – Service Operations.
• Perform the fuel injector balance test, refer to 6.3 Fuel Injector Balance
Test in this Section.
• Check the items that cause an engine to run rich.
Ignition System
• Inspect for moisture or corrosion around the spark plug and ignition coil area.
• Test the ignition coil voltage output. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Remove and inspect the spark plugs. Refer to 6C1-3 Engine Management –V6 –
Service Operations.
NOTE
If the spark plugs are fouled, determine the cause of the fouling before
replacing the spark plugs. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Check for loose ignition coil grounds.
Engine Mechanical
• Parasitic load on the engine such as the following:
• automatic transmission fault condition, or
• a belt driven accessory fault condition.
• Check for the following engine fault conditions. Refer to 6A1 Engine Mechanical –
V6.
• low compression, or
• worn valve train components.
When all diagnosis and repairs are completed, check the system for correct operation.
5.13 Surges / Chuggles
Description
W ith the accelerator pedal in a steady position, the vehicle speeds up and slows down or the engine power fluctuates.
Checks Actions
Preliminary Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this Section.
Sensor / System
• Using Tech 2, check the heated oxygen sensor (HO2s) operating parameters.
The HO2s should respond quickly to different throttle positions.
• Test the resistance of the crankshaft position (CKP) sensor. The CKP sensor
resistance must be 700 – 1,200 Ω at all temperatures.

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Engine Management – V6 – Diagnostics Page 6C1-2–36

Checks Actions
Fuel System
• Check the fuel system for the following fault conditions. Refer to 6C Fuel System
– V6.
• restricted fuel filter,
• incorrect fuel pressure, and
• contaminated fuel.
• Check the operation of the fuel injectors. Refer to 6C1-3 Engine Management –
V6 – Service Operations.
• Perform the fuel injector balance test, refer to 6.3 Fuel Injector Balance
Test in this Section.
• Check the items that cause an engine to run rich.
• Check for fault conditions that can cause an engine to run lean.
Ignition System
• Inspect for moisture or corrosion around the spark plug / ignition coil area.
• Test the ignition coil voltage output. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Remove and inspect the spark plugs. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
NOTE
If the spark plugs are fouled, determine the cause of the fouling before
replacing the spark plugs. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Check for loose ignition coil ground circuit.
Additional Checks
• Check the torque converter clutch (TCC) operation. A TCC that applies too soon
can cause engine detonation, which will trigger spark retard activity. Refer to 7C2
Automatic Transmission – 4L60E – Electrical Diagnosis.
• Test the A/C clutch for correct operation. Refer to 2A Heater and Air-conditioning.
• Check the evaporative emission (EVAP) canister purge solenoid for the following
conditions: Refer to 6C1-3 Engine Management – V6 – Service Operations.
− stuck open condition, and
− charcoal contamination.
• Check the exhaust system for possible restrictions. Refer to 6F Exhaust System –
V6.
• Electromagnetic interference (EMI) on the crankshaft position (CKP) sensor can
cause an engine misfire condition.
Using Tech 2, monitor the engine speed parameter. A sudden increase in the engine speed parameters without moving the throttle position indicates that an
Electromagnetic Interference fault may be present.
W iring harness routing which may be positioned very close to a high voltage or high current device such as the following may induce EMI:
• secondary ignition components, or
• motors and generators.
When all diagnosis and repairs are completed, check the system for correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–37

6 Functional Checks
6.1 General Information
The items detailed in the following pages are to be used when there is a customer complaint and there are no diagnostic
trouble codes set, or one or more of the Tech 2 data values are not within the typical values. They are also to be used
when instructed from a DTC table. Before using these tables, you should refer to 5 Symptoms Diagnostics in this
Section, which may direct you to using the following functional checks.
The purpose of these tables is to diagnose engine control module (ECM) controlled components or sub-systems that do
not have diagnostic trouble codes assigned to them. Another purpose of these tables is for Technicians who feel
confident that a particular part of the sub-system is not operating properly and wants only to check that particular item
for proper operation without going through lengthy diagnostic procedures.
6.2 Fuel Injector Coil Test
The fuel injector coil test is divided into two parts. Begin by performing the fuel injector coil quick test. Then only perform
the Injector Coil Test – W ith Special Tool J39021 procedure if the quick test determines that there is a faulty fuel injector.
Fuel Injector Coil Quick Test
Test Description
The following numbers refer to the step numbers in the diagnostic table:
1 This step checks if the engine coolant temperature is within the correct range.
2 This step tests each fuel injector resistance within a specific temperature range.
3 This step determines if all of the fuel injectors are within 3 ohms of each other.
Step Action Value(s) Yes No
1 Using Tech 2, observe the engine coolant temperature
(ECT).
Is the ECT within the specified range? 10 – 32 °C Go to Step 2 Go to Step 3
2 1 Disconnect the fuel injector harness connector,
refer to 2.13 Fuel Rail Assembly, in 6C1-3 Engine
Management – V6 – Service Operations.
2 Using a digital ohmmeter and connector test adaptor kit J 35616-A, measure the resistance of
each fuel injector between the ignition voltage
circuit and the fuel injector control circuit. Refer to
8A Electrical - Body and Chassis for information
on testing for continuity and to Figure 6C1-2 – 9
and Figure 6C1-2 – 10 for the fuel injector
harness connector.
Do any of the fuel injectors display a resistance outside
the specified range? 11 – 14 ΩRefer to Injector
Coil Test – W ith
Special Tool J39021 in this Section Injectors OK

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Engine Management – V6 – Diagnostics Page 6C1-2–39

Injector Coil Test – With Special Tool J39021
1 Depressurise the fuel system, refer to 6C Fuel System – V6.
2 Turn the ignition OFF.
NOTE
After removing the upper intake manifold, plug
the lower manifold opening to prevent dirt and
other contaminants from entering.
3 Remove the upper intake manifold assembly, refer to 6A1 Engine Mechanical – V6.
4 Using Tech 2, observe the engine coolant temperature (ECT). If the ECT is 10 – 32 °C, refer to Engine Coolant
Temperature Between 10 – 32 °C, or if the ECT is outside this range, refer to Engine Coolant Temperature Outside
10 – 32 °C.
Engine Coolant Temperature Between 10 – 32 °
°°
°
C
Step Action Value(s) Yes No
1 1 Set the amperage supply selector switch on the
fuel injector tester (1), special tool J 39021 to the
Coil Test 0.5 A position. Refer to
Figure 6C1-2 – 11.
2 Connect the fuel injector tester leads (4 and 5) to B+ and ground.
3 Connect the digital multimeter (2) positive and negative lead to the fuel injector tester. Set the
multimeter to read DC Voltage.
4 Connect the fuel injector tester, using fuel injector harness adapter, special tool J44602 to a fuel
injector.
5 Press the Push to Start Test button on the fuel injector tester.
6 Observe and record the voltage reading on the digital multimeter.
NOTE
The voltage reading may rise during the
test. Record the voltage reading after one
second of the test.
7 Repeat steps 4 through 6 for each fuel injector. NOTE
The table in Figure 6C1-2 – 12 shows an
example of the results from a fuel injector
coil test.
Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilise), or
voltage readings outside of the specified value? 5.5 – 6.6 V Replace the faulty
fuel injector/s. Refer to 2.13 Fuel Rail
Assembly, in 6C1-3 Engine
Management – V6 – Service Operations. System OK
When all repairs are completed, check the system for fuel leaks and correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–40

Engine Coolant Temperature Outside 10 – 32°
°°
°
C
Step Action Value(s) Yes No
1 1 Set the amperage supply selector switch on the
fuel injector tester (1), special tool J 39021 to the
Coil Test 0.5 A position. Refer to
Figure 6C1-2 – 11.
2 Connect the fuel injector tester leads (4 and 5) to B+ and ground.
3 Connect the digital multimeter (2) positive and negative lead to the fuel injector tester. Set the
multimeter to read DC Voltage.
4 Connect the fuel injector tester, using injector harness adapter, special tool J44602 to a fuel
injector.
5 Press the Push to Start Test button on the fuel injector tester.
6 Observe and record the voltage reading on the digital multimeter.
NOTE
The voltage reading may rise during the
test. Record the voltage reading after one
second of the test.
7 Repeat steps 4 through 6 for each fuel injector.
8 Identify the highest voltage reading recorded from the six fuel injectors tested that is 9.5 V or less.
NOTE
Disregard those voltage readings that are
greater than 9.5 V. Voltage readings greater
than 9.5 V indicate a faulty fuel injector.
9 Subtract the remaining voltage readings recorded in Step 8, from the highest voltage reading.
Are any of the values recorded in Step 9 greater than
the specified value? 0.6 V
Go to Step 2 System OK
2 1 Replace any fuel injector that has any of the
following:
− a subtracted value exceeding 0.6 V,
− an initial reading greater than 9.5 V, and
− an erratic reading.
NOTE
The table in Figure 6C1-2 – 13 shows an
example of the results from a fuel injector
coil test.
Has the repair been completed? – System OK. –
When all repairs are completed, check the system for fuel leaks and correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–42

6.3 Fuel Injector Balance Test

To avoid irregular fuel pressure readings, do
not perform this procedure if the engine
coolant temperature is greater than 94 °
°°
°
C.
Fuel Injector Balance Test – With Tech 2
1 Check the engine coolant temperature is less than 94 °C.
2 Perform the fuel injector coil test and replace any fuel injectors that are not functioning correctly before proceeding. Refer to 6.2 Fuel Injector Coil Test.
3 Perform the fuel system pressure check and ensure the fuel system is functioning correctly before proceeding with the fuel injector balance test. Refer to 6C Fuel System – V6.
4 W hile the fuel pressure gauge is still connected to the fuel pressure test point, pressurise the fuel system. Refer to 6C Fuel System – V6.
5 W hen the fuel pressure reading stabilises, record the fuel pressure reading indicated by the fuel pressure gauge.
NOTE
The fuel pressure reading taken in Step 5 is
known as the first pressure reading.
6 Connect Tech 2 to the data link connector (DLC) and turn the ignition on.
7 On Tech 2 select Engine / V6 Engine / Actuator Test / Fuel Injector Balance .
8 Follow the Tech 2 prompts, recording the fuel pressure gauge reading for each injector.
NOTE
The fuel pressure readings taken in Step 8 are
known as the second pressure reading
9 Perform the Fuel Injector Pressure Drop Calculation in this Section.
Fuel Injector Balance Test – Without Tech 2
1 Check the engine coolant temperature is less than 94 °C.
2 Perform the fuel injector coil test and replace any fuel injectors that are not functioning correctly before proceeding. Refer to 6.2 Fuel Injector Coil Test.
3 Perform the fuel system pressure check and ensure the fuel system is functioning correctly before proceeding with the fuel injector balance test. Refer to 6C Fuel System – V6.
4 W hile the fuel pressure gauge is still connected to the fuel pressure test point, pressurise the fuel system. Refer to 6C Fuel System – V6.
5 W hen the fuel pressure reading stabilises, record the fuel pressure reading indicated by the fuel pressure gauge.
NOTE
The fuel pressure reading taken in Step 5 is
known as the first pressure reading.

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Engine Management – V6 – Diagnostics Page 6C1-2–45


Clean around the area where the fuel
injectors enter the lower intake manifold.
3 Remove the bolt (1), three places, attaching the fuel rail to the lower intake manifold.

Care must be taken when removing the fuel
rail and injector assembly to prevent damage
to the injector spray tips and injector harness
connector terminals.
Support the fuel rail and injector assembly
after removal.
4 Lift up and support the fuel rail and injector assembly.
NOTE
Do not disconnect the fuel feed hose from the
fuel rail.
Figure 6C1-2 – 16
5 Place a board (1) with a sheet of clean paper (2), preferably white, onto the lower intake manifold.
6 Using Tech 2, enable the fuel pump to pressurise the fuel system.
7 W hilst the fuel system is pressurised, check the following:
• Signs of fuel stains on the paper (3).
• Signs of weeping at the fuel injector spray
tips (4).
8 If any of the above conditions are present, replace the leaking fuel injector/s, refer to 2.13 Fuel Rail
Assembly, in 6C1-3 Engine Management – V6 –
Service Operations.
9 Carefully reinstall the fuel rail and injector assembly.
Figure 6C1-2 – 17

Ensure the fuel injectors are correctly seated
in the lower intake manifold, and the fuel rail
attaching brackets are correctly located prior
to tightening the attaching bolts.
10 Tighten the fuel rail bolts to the correct torque specification. Fuel rail attaching bolt
torque specification ..................................8.0 – 12.0 Nm
11 Reinstall the upper intake manifold assembly, refer to 6A1 Engine Mechanical – V6.
12 Inspect the fuel rail and quick connect fitting for leaks, refer to 6C Fuel System – V6.
13 Road test the vehicle and check for correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–48

Additional Information
• Use the J 35616-B Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a
component harness connector.
• Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may
cause a condition with the ignition coils.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• 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 numbers below refer to the step numbers on the diagnostic table.
4 The ignition coils for each bank are fused separately. If a fuse opens or the ignition 1 voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground
circuit opens at the engine block, the ignition coils would be inoperative for one bank of the engine.
5 This step tests for an open or a high resistance in the ignition 1 voltage circuit of the ignition coil. If the DMM does not display near battery voltage there is an open or a high resistance in the circuit.
6 This step determines if the ground circuit is open. If the circuit is open, the ignition coils would be inoperative for one bank of the engine.
7 This step determines if the ignition 1 voltage circuit is shorted to ground. If the fuse is open, the ignition coils would be inoperative for one bank of the engine.
Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been performed? —
Go to Step 2 Refer to
4.4 Diagnostic System Check
2 W ere you sent here from DTC P0300 or P0301-P0306? —
Go to Step 3 Go to DTC P0300 or
DTC P0301 – P0306
3 1 Start the engine.
2 Allow the engine to reach operating temperature.
3 Operate the engine at 2,000 rpm.
4 Monitor all of the Misfire Current Counters with a scan tool. There are a total of 6 counters,
1 counter per cylinder.
Are any of the Misfire Current Counters incrementing? —
Go to Step 4 Go to
5.2 Intermittent Fault Conditions
4 Are all the misfire counters incrementing for one bank
of the engine? —
Go to Step 7 Go to Step 5
5 1 Ignition OFF.
2 Disconnect the appropriate ignition coil.
3 Ignition ON, engine OFF.
4 Connect a test lamp between the battery voltage circuit of the ignition coil and a good ground.
5 Measure the voltage between the probe of the test lamp and a good ground with a DMM. Refer
to 8A Electrical - Body and Chassis for the
procedure to measure voltage drop.
Is the voltage at the specified value? B+
Go to Step 6 Go to Step 9

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Engine Management – V6 – Diagnostics Page 6C1-2–62

DTC P0008, P0009 or P0016 Diagnostic Table
Step Action Yes No
1 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 Allow the engine to reach the normal operating temperature.
4 Increase the engine speed to 2,000 rpm for 10 seconds.
5 Using Tech 2, select the DTC display function.
Does DTC P0008, P0009 or P0016 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Are DTCs relating to the following DTCs also set:
• Camshaft actuator circuit
• CMP sensor circuit
• CKP sensor circuit Go to the
appropriate DTC
Table in this Section Go to Step 4
4 1 Inspect the engine for the following fault conditions. Refer to
6A1 Engine Mechanical – V6:
• incorrect installation of the CMP sensor,
• incorrect installation of the CKP sensor,
• timing chain tensioner fault condition,
• incorrectly installed timing chain,
• excessive play in the timing chain, and
• timing chain that jumped teeth.
W as any fault found and rectified? Go to Step 5 Refer to Additional
Information in this DTC
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 the DTC.
Does any of the crankshaft / camshaft position correlation DTCs 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.
7.3 DTC P0030, P0031, P0032, P0036, P0037,
P0038, P0050, P0051, P0052, P0056,
P0057 or P0058
DTC Descriptor
This diagnostic procedure supports the following DTCs:
• DTC P0030 – O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
• DTC P0031 – O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 1)

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Engine Management – V6 – Diagnostics Page 6C1-2–64

• Inspect the HO2S wiring harness for contact with the exhaust system.
• The front and the rear HO2Ss have a separate fuse connection. If both front or both the rear DTCs are set, the
appropriate HO2S ignition voltage circuit may be open.
• 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:
4 The ECM monitors the driver feedback circuit to determine if the heater control circuit is open, shorted to ground or shorted to a positive voltage. If the voltage is outside the specified range, there is a fault condition with the heater
control circuit.
DTC P0030 to P0032, P0036 to P0038, P0050 to P0052 and P0056 to P0058 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 Allow the engine to run at idle speed for at least 30 seconds.
4 Increase the engine speed to 2,000 rpm for 10 seconds.
5 Using Tech 2, select the DTC display function.
Does DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050,
P0051, P0052, P0056, P0057 or P0058 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Disconnect the appropriate HO2S wiring connector.
2 Switch on the ignition with the engine not running.
3 Connect a test lamp between the HO2S heater ignition voltage circuit and the ECM housing.
Does the test lamp illuminate? Go to Step 4 Go to Step 5
4 Using a digital multimeter, measure the voltage between the HO2S
heater control circuit and a good ground.
Does the multimeter display:
• HO2S 1: 4.6 – 5.2 V?
• HO2S 2: 2.8 – 4.2 V? Go to Step 7 Go to Step 6
5
NOTE
The HO2S ignition voltage circuit is shared with other
sensors. Ensure that all circuits and components that
share this ignition voltage circuit are tested for a short to
ground.
Repair the high resistance open circuit or short to ground fault
condition in the HO2S heater ignition voltage circuit. Refer to 8A
Electrical - Body and Chassis for information on electrical wiring
repair procedures.
W as the repair completed? Go to Step 9 —

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