2007 ISUZU KB P190 Harness

Engine Cooling – V6 Engine Page 6B1–54

3.15 Radiator
Remove

Refer to 3.1 Service Notes in this Section, for
important safety items.
1 Allow engine to cool to ambient temperature (less than 50 ° C), then remove coolant filler cap.

Disconnection of the battery affects certain
vehicle electronic systems. Refer to 00
Warnings, Cautions and Notes, before
removing the ground lead.
2 Disconnect the battery ground lead. Refer to 8A – Electrical Body & Chassis.
3 Depress the tang on the main wiring harness to the cooling fan motor wiring harness connector (1) and
separate the connector.
4 Remove the radiator cooling fan and shroud assembly. Refer to 3.13 Cooling Fan and Shroud
Assembly in this Section.
5 Drain the coolant from the system. Refer to 3.3 Draining and Filling Cooling System in this
Section.



Refer to ‘
‘‘
‘
Environmental Issues ’
’’
’
in 3.1
Service Notes, before draining the
coolant.

Figure 6B1 – 62








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Engine Cooling – V6 Engine Page 6B1–66

6 Torque Wrench Specifications
N.m
Coolant Outlet housing to Engine Outlet Attaching Bolts............................... 10
Coolant Pump to Front Cover Attaching Bolts ............................................... 10
Coolant Pump Pulley Attaching Bolts ............................................................ 12
Coolant Inlet Pipe to Thermostat Housing Attaching Bolt .............................. 23
Fan Motor Assembly to Shroud Attaching Screws .......................................... 5
Heater Pipe Assembly to Thermostat Housing Attaching Bolts ..................... 10
Heater Pipe Assembly to Cylinder Head Attaching Bolt ................................ 35
Thermostat Housing to Engine Block Attaching Bolts.................................... 10
Rear Engine Harness .................................................................................... 15
Engine Harness Ground Terminal ................................................................. 12
Coolant Inlet Pipe To Engine Block Bolt ........................................................ 25
Transmission Cooler Lines Bracket .............................................................. 23


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Fuel System – V6 Page 6C – 7

Fuel Flow
Fuel (A) is drawn into the modular fuel pump and sender
assembly reservoir from the fuel tank, through the primary
umbrella valve (5) and into the fuel pump impeller, via the
internal strainer (4) at the fuel pump (1) inlet. At the impeller,
vapour (C) is separated from the fuel. The vapour is ejected
from the fuel pump into the reservoir via a port next to the
fuel pump inlet.
High-pressure fuel then flows through the end cap, the lower
connector and the flexible line. From the flexible line, fuel
exits the modular fuel pump and sender assembly through
the fuel feed port and flows on to the externally-mounted
fuel filter and the engine.
A fuel pressure regulator is located in the modular fuel pump
and sender assembly; fuel not used by the engine (B) is
returned to the modular fuel pump and sender assembly via
the fuel return line and the fuel return port in the modular
fuel pump and sender assembly cover. The return fuel
enters the jet pump standpipe (3) of the reservoir via the
return fuel tube.
Vehicle fuel line pressure is maintained by a pressure
regulator (2) located within the modular fuel pump and
sender assembly.
W hen the engine is switched off, the reservoir remains full of
fuel, due to the action of the primary umbrella valve. At high
fuel levels, fuel tank overflow enters the reservoir over the
top of the reservoir. Fuel level in the reservoir is also
maintained by returned engine fuel.
Electrical power is supplied to the fuel pump by a connector
secured to the modular fuel pump and sender assembly
cover. An internal harness (not shown) assembly completes
the connection to the pump.
Figure 6C – 3


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ISUZU KB P190 2007

Engine Management – V6 – General Information Page 6C1-1–13

• The accelerator pedal assembly which includes:
− The accelerator pedal,
− The accelerator pedal position (APP) sensor
one, and
− The accelerator pedal position (APP) sensor two.
Figure 6C1-1 – 7

To avoid serious personal injury, never
attempt to rotate the throttle plate manually
whilst the throttle body harness connector is
connected to the throttle body.
• The throttle body assembly which includes:
− the throttle position (TP) sensor one
− the throttle position (TP) sensor two
− the throttle actuator control (TAC) motor, and
− the throttle plate.
• The engine control module (ECM).
Figure 6C1-1 – 8
The ECM monitors the accelerator pedal position through the two APP sensors and processes this information, along
with other system sensor inputs, to command the throttle plate to a certain position.
The throttle plate is controlled by a direct current motor called the throttle actuator control motor. The ECM operates this
motor in the forward or reverse direction by controlling battery voltage and / or ground to two internal drivers. The throttle
plate is held at a rest position of seven percent open using a constant force return spring. This spring holds the throttle
plate to the rest position when there is no current flowing to the actuator motor.
The ECM monitors the throttle plate angle through two TP sensors. Using this information, the ECM can precisely adjust
the throttle plate.
The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors and the throttle
actuator control motor circuit. It also monitors the spring return rate. These diagnostics are performed at different times
based on whether the engine is running, not running, or whether the ECM is currently in a throttle body relearn procedure.
Two sensors within the accelerator pedal assembly and throttle body assembly are used to provide redundancy. If a
malfunction is detected, the throttle plate is moved to a pre-determined position.
Every ignition cycle, the ECM performs a quick throttle return spring test to ensure the throttle plate can return to the
seven percent rest position from the zero percent position. This is to ensure the throttle plate can be brought to the rest
position in case of an actuator motor circuit failure.

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Engine Management – V6 – General Information Page 6C1-1–27

4.13 Fuel Rail Assembly
The fuel rail assembly is mounted on the lower intake
manifold and distributes the fuel to each cylinder through
individual fuel injectors. The fuel rail assembly consists of:
• the pipe that carries fuel to each injector,
• a fuel pressure test port,
• six individual fuel injectors,
• wiring harness, and
• wiring harness tray.
Figure 6C1-1 – 31
4.14 Heated Oxygen Sensors
The heated oxygen sensors (HO2S) are mounted in the exhaust system and enable the ECM to measure oxygen
content in the exhaust stream. The ECM uses this information to accurately control the air / fuel ratio, because the
oxygen content in the exhaust gas is indicative of the air / fuel ratio of engine combustion.
W hen the sensor is cold, it produces little or no signal voltage, therefore the ECM only reads the HO2S signal when the
HO2S sensor is warm. As soon as the HO2S are warm and outputting a usable signal, the ECM begins making fuel
mixture adjustments based on the HO2S signals. This is known as closed loop mode.
The HFV6 engine has four HO2S, one LSU 4.2 wide-band planar type HO2S upstream of the catalytic converter in each
exhaust pipe, and one LSF 4.2 two-step planar type HO2S in each exhaust pipe downstream of the catalytic converter.
LSF 4.2 Two-step Planar Heated Oxygen Sensors
The LSF 4.2 two-step planar heated oxygen sensors have
four wires:
• The internal heater element supply, which has 12 V
continually applied whenever the ignition is on.
• Heater element ground – The ECM applies pulse
width modulated (PW M) ground to the HO2S heater
control circuit to control the rate at which the sensor
heats up. This reduces the risk of the sensor being
damaged from heating up too quickly under certain
conditions such as extreme cold temperatures. Once
the sensor has reached the desired operating
temperature, the ECM will monitor and continue to
maintain the sensor temperature.
• Sensor signal to the ECM.
• Sensor ground.
Legend
1 Protective Tube
2 Ceramic Seal Packing
3 Sensor Housing
4 Ceramic Support Tube
5 Planar Measuring Element
6 Protective Sleeve
7 Connection Cable
Figure 6C1-1 – 32

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Engine Management – V6 – Diagnostics Page 6C1-2–19

• Do not start the engine if the battery terminal is not properly secured to the battery.
• Do not disconnect or reconnect the following while the ignition is switched on or when the engine is running:
− Any engine management system component electrical wiring connector, or
− Battery terminal leads.
• Ensure the correct procedure for disconnecting and connecting engine management system electrical wiring
connectors is always followed. For information on the correct procedure for disconnecting and connecting specific
wiring connectors, refer to 6C1-3 Engine Management – V6 – Service Operations.
• Ensure that all wiring harness connectors are fitted correctly.
• W hen steam or pressure cleaning engines, do not direct the cleaning nozzle at engine management system
components.
• Do not clear any DTCs unless instructed.
• The fault must be present when using the diagnostic trouble code (DTC) diagnostic tables. Otherwise,
misdiagnosis or replacement of good parts may occur.
• Do not touch the ECM connector pins or soldered components on the ECM circuit board to prevent ECM
Electrostatic Discharge damage. Refer to 8A Electrical - Body and Chassis for information on Electrostatic
Discharge.
• Use only the test equipment specified in the diagnostic tables as other test equipment may give incorrect results or
damage good components.
• The ECM is designed to withstand normal current draw associated with vehicle operations. However, the following
fault conditions or incorrect test procedure may overload the ECM internal circuit and damage the ECM:
− A short to voltage fault condition in any of the ECM low reference circuits may cause internal ECM and / or
sensor damage. Therefore, any short to voltage fault condition in the ECM low reference circuits must be
rectified before replacing a faulty component.
− A short to ground fault condition in any of the ECM 5 V reference circuits may cause internal ECM and / or
sensor damage. Therefore, any short to ground fault condition in the ECM 5 V reference circuits must be
rectified before replacing a faulty component.
− W hen using a test lamp to test an electrical circuit, do not use any of the ECM low reference circuits or 5 V
reference circuits as a reference point. Otherwise, excessive current draw from the test lamp may damage
the ECM.
• Disregard DTCs that set while performing the following diagnostic Steps:
− Using Tech 2 actuator tests, or
− Disconnecting an engine management system sensor connector then switching on the ignition.
• After completing the required diagnostics and service operations, road test the vehicle to ensure correct engine
management system operation.
4.3 Preliminary Checks
The preliminary checks are a set of visual and physical checks or inspections that may quickly identify engine
management system fault condition.
• Refer to the appropriate Service Techlines for relevant information regarding the fault condition.
• Ensure the battery is fully charged.
• Inspect the battery connections for corrosion or a loose terminal.
• Ensure that all engine management system related fuses are serviceable.
• Inspect for incorrect aftermarket theft deterrent devices, lights or mobile phone installation.
• Ensure there is no speaker magnet positioned too close to any electronic module that contains relays.
• Inspect the engine wiring harness for proper connections, pinches or cuts.
• Ensure that all engine management related electrical wiring connectors are fitted correctly.
• Inspect the ECM ground connections for corrosion, loose terminal or incorrect position.

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Engine Management – V6 – Diagnostics Page 6C1-2–20

• Ensure the resistance between the ECM housing and the battery negative cable is less than 0.5 Ω.
• Check the ECM bracket fasteners for correct torque value.
• Check all engine management related components for correct installation.
• Inspect the vacuum hoses for splits, kinks, oil contamination and proper connections, refer to the vehicle emission
control information label. Check the hoses thoroughly for any type of leak or restriction.
• Inspect the air intake ducts for being collapsed, split or for having damaged areas.
• Inspect for air leaks at the throttle body mounting area, mass air flow (MAF) sensor, intake manifold and intake
manifold sealing surfaces.
• Check for wiring harness routing that may be positioned too close to a high voltage or high current device such as
the following:
− Secondary ignition components, and
− Motors and generators.
NOTE
High voltage or high current devices may induce
electrical noise on a circuit, which can interfere
with normal circuit operation.
4.4 Diagnostic System Check
Description
The engine management diagnostic procedure is organised in a logical structure that begins with the Diagnostic System
Check. The Diagnostic System Check directs the diagnostic procedure to the logical steps necessary to diagnose an
engine driveability fault condition.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
6 Tests the integrity of the GM LAN serial data communication circuit. A PIM DTC sets if the PIM detects a fault condition in the communication circuit. A fault condition on the serial data communication circuit may trigger
multiple DTCs on other sensors and components.
Step Action Yes No
1 Have you read the basic requirements?
Go to Step 2 Refer to
4.1 Basic
Requirements
2 Have you read the diagnostic precautions?
Go to Step 3 Refer to
4.2 Diagnostic Precautions
3 Have you performed the preliminary checks?
Go to Step 4 Refer to
4.3 Preliminary Checks
4 Using Tech 2, attempt to communicate with the PIM.
Does the PIM fail to communicate? Refer to 6E1
Powertrain Interface Module – V6 Go to Step 5
5 Does DTC B3902, C0550, U2100, U2105, U2106, P0633, or P1611
also set in the PIM? Refer to 6E1
Powertrain Interface Module – V6 Go to Step 6
6 Using Tech 2, view and record DTCs set at the ECM and TCM.
Does Tech 2 display any DTC? Go to Step 7 Refer to
5.1 Symptoms
Diagnosis Table

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Engine Management – V6 – Diagnostics Page 6C1-2–23

• there is no Current DTC but a History DTC is stored.
Diagnostic Table
Checks Actions
Preliminary
• Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Gather information from the customer regarding the conditions that trigger the
intermittent fault such as:
• At what engine or ambient temperature range does the fault occur?
• Does the fault occur when operating aftermarket electrical equipment inside
the vehicle?
• Does the fault occur on rough roads or in wet road conditions?
• If the intermittent fault is a start and then stall condition, check the immobiliser
system. Refer to 11A Immobiliser.
Tech 2 Tests The following are lists of Tech 2 diagnostic tests that may be used to diagnose
intermittent faults:
• W riggle test the suspected wiring harness and connectors while observing Tech 2
operating parameters. If Tech 2 read-out fluctuates during this procedure, check
the tested wiring harness circuit for a loose connection.
• Observe the freeze frame / failure records for the suspected history DTC and then
operate the vehicle in the conditions that triggers the intermittent fault while an
assistant observes the suspected Tech 2 operating parameter data.
• Capture and store data in the snapshot mode when the fault occurs. The stored
data may be played back at a slower rate to aid diagnostics. Refer to Tech 2 User
Instructions for further information on the Snapshot function.
• Compare the engine operating parameters of the engine being diagnosed to the
engine operating parameters of a known good engine.
Malfunction Indicator Lamp The following conditions may cause an intermittent Malfunction Indicator Lamp fault with no DTC listed:
• Electromagnetic interference (EMI) caused by a faulty relay, ECM controlled
solenoid, switch or other external source.
• Incorrect installation of aftermarket electrical equipment such as the following:
• mobile phones,
• lights, or
• radio equipment.
• ECM grounds are loose.

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