lock ISUZU KB P190 2007 Workshop Repair Manual

Engine Management – V6 – Diagnostics Page 6C1-2–31

Checks Actions
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.
Engine Cooling System Check the engine thermostat for correct operation and heat range. Refer to 6B1 Engine
Cooling – V6.
Additional Checks • Check the generator output voltage. Refer to 6D1-1 Charging System – V6.
When all diagnosis and repairs are completed, check the system for correct operation.
5.10 Lack of Power, Sluggishness or
Sponginess
Description
The engine delivers less than normal power. There is little or no increase in vehicle speed when the accelerator pedal is
partially depressed.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the air filter element and intake air ducts for blockages.
Sensor / System
• Use Tech 2 to monitor the knock sensor system for excessive spark retard
activity. Check for items that cause spark retard activity.
• Inspect the accelerator pedal position (APP) sensor harness connector for correct
connection. Poor connection of this connector will not set a DTC.
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 for fault conditions that can cause the engine to run rich or run lean.

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Engine Management – V6 – Diagnostics Page 6C1-2–32

Checks Actions
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.
Engine Mechanical
• Check for the following engine mechanical fault condition. Refer to 6A1 Engine
Mechanical – V6.
• low engine compression, and
• worn valve train components.
Additional Checks
• Check the exhaust system for possible restrictions. Refer to 6F Exhaust System –
V6.
• Test for other TCM related faults that may cause the transmission to operate in
the default mode.
• Check for transmission mechanical faults that may produce similar symptoms
such as slipping clutch.
When all diagnosis and repairs are completed, check the system for correct operation.
5.11 Poor Fuel Economy
Description
As confirmed by an actual road test, the fuel economy as compared to the previous fuel consumption of the same
vehicle is noticeably lower.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the air filter element and intake air ducts for blockages.
• Check for correct tyre pressure. Refer to the Owners Manual.
• Check the recent driving conditions are the same compared to the previous when
the fuel consumption is normal. The following are list of driving conditions that
may affect fuel consumption:
− vehicle load,
− acceleration rate,
− A/C or other electrical equipment use, and
− vehicle used for towing.

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Engine Management – V6 – Diagnostics Page 6C1-2–34

Checks Actions
Additional Checks
• 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, and
• motors and generators.
• 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 for other TCM related faults that may cause the transmission to operate in
the default mode. Refer to 7C2 Automatic Transmission – 4L60E – Electrical
Diagnosis.
• Check for transmission mechanical faults such as slipping clutch. Refer to 7C3
Automatic Transmission – 4L60E – Hydraulic and Mechanical Diagnosis.
• Check the brake system including the parking brake for sticking or incorrect
operation.
When all diagnosis and repairs are completed, check the system for correct operation.
5.12 Rough, Unstable, Incorrect Idle or
Stalling
Description
Engine idle speed fluctuates causing the engine to run unevenly. If the engine idle speed drops too low, the engine may
stall.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the air filter element and intake air ducts for blockages.
Sensor / System
• Check the throttle actuator control (TAC) system. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
• Check the air intake system and crankcase for air leaks. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
• Check the PCV System for correct operation. Refer to 6A1 Engine Mechanical –
V6.
• Use Tech 2 to monitor the knock sensor system for excessive spark retard
activity. Check for items that cause spark retard activity.
• Using Tech 2, check the heated oxygen sensor (HO2s) operating parameters.
The HO2s sensor should respond quickly to different throttle positions.

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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 6C1-2–70

Additional Information
• The MAF sensor circuit DTCs 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.
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the MAF sensor operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Inspect the MAF sensor for an incorrectly routed harness or if the harness is too close to the following:
− ignition coil,
− solenoids,
− relays, and
− motors.
• A low minimum air rate may cause this DTC to set during deceleration. Inspect for the following conditions:
− a plugged or a collapsed intake air duct, or a dirty air filter element,
− objects that block the MAF sensor air inlet screen, and
− sticking or dirty throttle plate or throttle bore.
• Any un-metered air that enters the engine may cause this DTC to set. Inspect for vacuum leaks in the following:
− intake manifold,
− throttle body,
− barometric pressure (BARO) sensor seal,
− EVAP canister purge valve seal,
− brake booster system,
− air induction system, and
− crankcase ventilation system.
• 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.
DTC P0101, P0102 or P0103 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 P0101, P0102 or P0103 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC

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Engine Management – V6 – Diagnostics Page 6C1-2–71

Step Action Yes No
3 Inspect for the following fault conditions:
• engine vacuum leak,
• air leak in the intake air duct between the MAF sensor and the
throttle body,
• plugged or collapsed intake air duct,
• objects that block the MAF sensor inlet screen,
• restricted air filter element,
• restricted throttle plate or carbon build-up around the throttle
plate,
• unseated engine oil dipstick,
• loose or missing engine oil cap, and
• over filled crankcase.
W as any fault found and rectified? Go to Step 14 Go to Step 4
4 1 Disconnect the MAF sensor wiring connector.
2 Connect a test lamp between the MAF sensor ignition voltage circuit and the ECM housing.
3 Switch on the ignition with the engine not running.
Does the test lamp illuminate? Go to Step 5 Go to Step 11
5 1 Switch on the ignition with the engine not running.
2 Using a digital multimeter, measure the voltage between the MAF sensor 5 V reference circuit and the ECM housing.
Does the multimeter display 4.8 – 5.2 V? Go to Step 6 Go to Step 8
6 1 Switch off the ignition.
2 Connect a 3 A fused jumper wire between the MAF sensor 5 V reference circuit and signal circuit.
3 Switch on the ignition with the engine not running.
4 Using Tech 2, observe the MAF sensor voltage parameter.
Does Tech 2 display 4.8 – 5.2 V? Go to Step 7 Go to Step 9
7 1 Switch off the ignition.
2 Remove ECM Fuse 29 from the engine compartment fuse and relay panel assembly.
3 Using a digital multimeter, measure the resistance between the MAF sensor low reference circuit and the ECM housing.
NOTE
Install ECM Fuse 29 to the engine compartment fuse and
relay panel assembly after completing the test.
Does the multimeter display 5 Ω? Go to Step 12 Go to Step 10

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Engine Management – V6 – Diagnostics Page 6C1-2–244

Precondition: Ignition ‘On’.
Cooling Fan (PWM)
Take care that no-one can access the engine
compartment during these tests!
This test allows the Technician to turn the cooling fan on in increments to its maximum speed.
Precondition: Ignition ‘On’ Air conditioning is ‘Off’..
Alternator L Terminal
This test allows the Technician to turn ‘On’ and ‘Off’, the commanded state of the voltage regulator in the alternator. ‘On’
displays a commanded state of 99%, while ‘Off’ displays a commanded state of 0%.
Precondition: Engine running.
EVAP Purge Solenoid
This test allows the Technician to control the EVAP purge solenoid valve. The normal commanded state is ‘0%’. The
system will increase or decrease the amount of purge by changing the duty cycle of the purge valve in 10% increments
within a range of 0 – 100%. The system will remain in the commanded state until cancelled by Tech 2.
NOTE
The EVAP Purge Solenoid Command parameter
may not change states when using this output
control.
Precondition: Ignition ‘On’, engine ‘Off’.
Engine Speed Control

Other DTCs may set when the Engine Speed
Control function is used. Disregard those
DTCs that set under this condition.
Allows the increase / decrease of the engine speed in 20 – 30 rpm increments from the base idle speed, up to 1,600
rpm.
NOTE
If the engine coolant temperature is below the
prescribed minimum, a message to that effect is
displayed and access to engine speed control is
blocked.
Preconditions: Engine running, engine temperature above 80 °C, transmission in Park or Neutral.

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Engine Management – V6 – Service Operations Page 6C1-3–2

Reinstall ................................................................................................................................................................ 20
ECM Reset ...................................................................................................................... ...................................... 20
2.8 Engine Control Module Bracket Assembly......................................................................................... ............... 21
Remove ................................................................................................................................................................. 21
Reinstall ................................................................................................................................................................ 21
2.9 Engine Oil Level and Temperature Sensor ........................................................................................ ................ 22
Remove ................................................................................................................................................................. 22
Test ....................................................................................................................................................................... 23
Engine Oil Level Sensor Check .................................................................................................. ...................... 23
Reinstall ................................................................................................................................................................ 23
2.10 Engine Oil Pressure Sensor..................................................................................................... ........................... 23
Remove ................................................................................................................................................................. 23
Reinstall ................................................................................................................................................................ 24
2.11 Evaporative Emission (EVAP) Canister Purge Valve Quick Connect Fittings ................................................ 24
Disconnect..................................................................................................................... ....................................... 24
Locking Lever Type ............................................................................................................. ............................. 25
Latch Type ....................................................................................................................................................... 25
Connect ............................................................................................................................................................ 25
2.12 Evaporative Emission Canister Purge Valve ...................................................................................... ............... 26
Remove ................................................................................................................................................................. 26
Test ....................................................................................................................................................................... 27
Resistance Check ............................................................................................................... ............................. 27
Functional Test................................................................................................................................................. 27
Reinstall ................................................................................................................................................................ 28
2.13 Fuel Rail Assembly ............................................................................................................. ................................. 28
Remove ................................................................................................................................................................. 28
Disassemble ......................................................................................................................................................... 30
Fuel Injector ..................................................................................................................................................... 30
Fuel Injector Wiring Harness Assembly.......................................................................................... .................. 32
Reinstall ................................................................................................................................................................ 33
2.14 Heated Oxygen Sensor........................................................................................................... ............................. 33
Service Precautions............................................................................................................................................. 33
Six Wire Sensor................................................................................................................................................ 34
Four Wire Sensor ............................................................................................................... .............................. 35
Test ....................................................................................................................................................................... 37
Heater Resistance Check – Six Wire HO2S........................................................................................ ............. 37
Heater Resistance Check – Four Wire HO2S ....................................................................................... ........... 37
2.15 Ignition Coil .......................................................................................................................................................... 38
Ignition Coils ................................................................................................................. ....................................... 38
Remove ............................................................................................................................................................ 38
Disassemble..................................................................................................................................................... 39
Reassemble ..................................................................................................................................................... 39
Test .................................................................................................................................................................. 39
Reinstall ........................................................................................................................................................... 40
2.16 Intake Air Duct Assembly....................................................................................................... ............................. 40
Remove ................................................................................................................................................................. 40
Reinstall ................................................................................................................................................................ 40
2.17 Intake Air Temperature Sensor .................................................................................................. ......................... 41
Test ....................................................................................................................................................................... 41
Resistance Check ............................................................................................................... ............................. 41
2.18 Knock Sensor, Bank 2 (LHS)..................................................................................................... .......................... 42
Remove ................................................................................................................................................................. 42
Reinstall ................................................................................................................................................................ 43
2.19 Knock Sensor, Bank 1 (RHS) ..................................................................................................... ......................... 43
Remove ................................................................................................................................................................. 43
Reinstall ................................................................................................................................................................ 44
2.20 Mass Air Flow Sensor........................................................................................................... ............................... 45
Handling Precautions .......................................................................................................................................... 45
Remove ................................................................................................................................................................. 45
Reinstall ................................................................................................................................................................ 46

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Engine Management – V6 – Service Operations Page 6C1-3–11

3 Using a suitable lever, gently lever the locking tangs
(1) of the lower housing insulator sleeve back to clear
the lower housing retaining bolt (2). Repeat this
process for each of the remaining two sleeves.
4 Remove the three bolts retaining the lower housing (3) to the fender inner panel and remove the housing.
5 If required, remove the insulator sleeve and air cleaner lower housing insulator (4).
Figure 6C1-3 – 4

Reinstall
1 Reinstall the air cleaner lower housing attaching bolt and tighten to the correct torque specification.
Air cleaner lower housing attaching
bolt torque specification ..........................18.0 – 22.0 Nm
2 Using a suitable hammer and pin punch, position the locking tang against the bolt head.
3 Road test the vehicle and check for correct operation.
2.3 Barometric Pressure Sensor
Remove
1 Turn the ignition switch off.
2 Disconnect the wiring harness connector (1) from the barometric pressure (BARO) sensor (2).

Figure 6C1-3 – 5

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Engine Management – V6 – Service Operations Page 6C1-3–14

3 Disconnect the wiring harness connector (1) from the
crankshaft position (CKP) sensor (2).
Figure 6C1-3 – 9

Clean the area around the CKP sensor before
removal to avoid debris from entering the
engine.
4 Remove the CKP sensor attaching bolt (1).
5 Remove the CKP sensor (2), by first twisting the sensor to release it, and then pulling it away from the
engine block to remove it.
6 If required, test the CKP sensor, refer to the Test in this Section.
Figure 6C1-3 – 10

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