2007 ISUZU KB P190 Neutral switch

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

Basic Diagnostic Tools Required

Use of incorrect electrical circuit diagnostic
tools when performing certain service
procedures could result in incorrect
diagnostic results or damage to components.
The following electrical circuit testing tools are required to perform the diagnostic procedures detailed in this Section:
• Test lamp, refer to 8A Electrical – Body and Chassis for further information.
• Digital multimeter with 10 M Ω ohms impedance, refer to 8A Electrical – Body and Chassis for further information.
• Connector test adapter kit Tool No. J35616-A.
1.3 Service Operations Not Covered In This
Section
There are situations where components and/or procedures related to the powertrain management system are covered in
other Sections of the service documentation. To aid technicians in locating the necessary service procedures for these
components and/or procedures, refer to the stated references.
Air-conditioning System
For A/C pressure switch replacement procedure, refer to 2A Heater and Air-conditioning.
Electrical Components
For the following electrical system component replacement procedures, refer to the appropriate Sections as follows:
• Extended brake pedal travel switch and stop lamp switch service operations, refer to 5C Brakes.
• Fuse and relay locations, refer to 8A Electrical-Body and Chassis.
• Cruise control switch assembly service operations, refer to 8C Cruise Control – HFV6.
• Powertrain interface module PIM removal and installation procedure, refer to 6E1 Powertrain Interface Module – V6.
• Neutral start and back-up lamp switch, refer to 7C4 Automatic Transmission – 4L60E – On-vehicle Servicing.
• Vehicle speed sensor service operations, refer to:
− 7C4 Automatic Transmission – 4L60E – On-vehicle Servicing
− 7B1 Manual Transmission – V6
Fuel System
For the following fuel system component replacement procedures, refer to 6C Fuel System – V6.
• Fuel system cleaning,
• Fuel system leak and pressure test,
• Fuel feed hose to fuel rail replacement,
• Fuel line quick connect fittings,
• Evaporative emission control canister,
• Fuel filter,
• Fuel hose / pipes layout,
• Fuel pump motor assembly and fuel pressure regulator assembly,
• Fuel sender assembly service operations.

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–4

• Clarify a procedure,
• Present additional information for accomplishing a procedure,
• Give insight into the reasons for performing a procedure in the recommended manner, and / or
Present information that gives the technician the benefit of past experience in accomplishing a procedure with greater
ease.
1.2 Components
Starting System Components
The main components of the starting system are:
• battery,
• wiring,
• ignition switch,
• theft deterrent engine crank inhibitor (a function of the theft deterrent system),
• park / neutral and back-up switch (on vehicles with 4 speed automatic transmission),
• engine control module (ECM),
• start relay,
• solenoid switch, and
• starter motor.
Starter Motor and Solenoid Switch Components
Solenoid Switch
The solenoid switch is used to activate the DC motor and has two windings; the pull-in winding and the hold-in winding.
The pull-in winding has heavier wire and is grounded through the DC motor winding and brushes. The hold-in winding is
grounded through the solenoid casing.
Planetary Drive Train
The planetary drive train consists of an internally toothed ring gear and three planetary gear wheels, which rotate on
sleeve bearings on the planetary drive shaft. The ring gear is keyed into the drive-end housing and is made from
high-grade polyamide with mineral additives.
W hen the starter motor operates, the armature turns the planetary gears inside the fixed planetary ring gear. This drives
the planetary shaft at a reduced speed ratio which turns the drive assembly. A fork lever in the drive-end housing forces
the drive assembly forward to engage with the flexplate / flywheel ring gear on the engine and transmit cranking torque.
An internal clutch allows the drive assembly pinion gear to rotate freely when the engine starts. This prevents the
armature from being driven at excessive speed by the engine.
Armature
The armature shaft is supported at each end by oil absorbent, sintered metal bushes; one in the commutator end shield
and one in the planetary drive shaft. The front end of the armature has a gear profile. This meshes with the three
planetary gear wheels. These in turn, mesh with the internal teeth of the ring gear.
Brushes
A brush plate supports four commutator brushes. This plate is fixed to the commutator end shield with two retaining
screws. Two negative brushes are grounded to the pole housing. The two positive brushes are insulated from the pole
housing and connected to the solenoid switch M terminal, refer to Figure 6D1-2 – 1.

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–5


Figure 6D1-2 – 1
Legend
1 Solenoid Switch
1 Starter Motor
3 Starter Motor terminal M 4 Connector P-4
5 Connector P-3 – pin 1
1.3 System Operation
Operation
The ECM controls the activation of the start relay in response to inputs from:
• ignition switch,
• battery,
• theft deterrent engine crank inhibitor (a function of the theft deterrent system),
• park / neutral and back-up switch (on vehicles with 4 speed automatic transmission),
The start relay controls the operation of the start solenoid.
The start solenoid controls operation of the starter motor and the drive assembly.

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–6

Sequence of Operation
1 W hen the ignition switch is turned to the START position, a signal is also sent to the ECM to request the engine to
crank.
• For automatic vehicles the transmission must be in either park (P) or neutral (N) for the ECM to allow
cranking to commence.
• The ECM will only allow cranking if the battery voltage is above the minimum battery voltage threshold value,
refer to 6C1-1 Engine Management – V6 – General Information for further information.
2 The ECM operates the start relay which provides power to the pull-in winding of the start solenoid.
3 Current flow to the pull-in winding develops powerful magnetism which pulls in the solenoid switch plunger.
4 The plunger closes the switch contacts connecting battery voltage to the DC motor and pivots the fork lever to engage the drive assembly to the flexplate / flywheel ring gear. Closing the solenoid switch contacts deactivates the
pull-in winding, the hold-in winding remains active.
5 W ith the solenoid switch contacts closed, current flows from the battery through the DC motor, which rotates the armature at high speed and provides cranking torque.







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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–10

2.5 Starting System Inoperative /
Malfunctioning
Circuit Description
The battery cable supplies a constant connection from the battery to starter solenoid connector P – 4.
W hen the ignition switch is turned to the START position, 12 V is applied to the ECM connector C – 56 pin 31.
For vehicles with 4 speed automatic transmission, when the transmission is in park (P) or neutral (N), the park / neutral
and back-up switch grounds ECM connector C – 56 pin 32.
The ECM provides a ground for the start relay, ECM connector C – 56 pin 35 to start relay connector X – 13 pin 5.
W hen activated the start relay provides 12 V to starter solenoid connector P – 3 pin 1.
The solenoid closes its switch contacts to connect the battery voltage at the solenoid switch terminal P – 4 terminal B to
the DC motor. The pull-in winding of the solenoid switch is grounded through the DC motor winding and brushes. The
hold-in winding is grounded through the solenoid casing. The DC motor is grounded through the starter motor casing.
Refer to 2.4 W iring Diagram to aid in diagnosis.
Diagnostic Table Notes
Reference to following information will assist when diagnosing starting circuit faults:
1 If the battery, starter motor and fuel system are deemed as serviceable and a ‘no crank’ and / or ‘no start’ condition exists, refer to the following Sections as required:
a 11A Immobiliser for theft deterrent engine crank inhibitor related faults
b 6C1-2 Engine Management V6 Diagnostics, for starter relay circuit faults
2 For all wiring harness fault diagnoses, refer to 8A Electrical Body and Chassis.
3 For wiring harness repairs, refer to 8A Electrical Body and Chassis.
4 Refer to 8A Electrical Body and Chassis for harness routing.
5 Ensure the battery, cables and connections are in good order. Refer to 8A Electrical Body and Chassis.
Diagnostic Table
Step Action Yes No
1
Did you review 1.3 System Operation?
Go to Step 2 Go to 1.3
System
Operation
2 Did you read 2.3 Diagnostic Systems Check
Go to Step 3 Go to 2.3
Diagnostic Systems Check
3 Turn the ignition switch to the START position and then release it.
Did the engine crank or were there any clicking or chattering sounds
from the solenoid? Go to Diagnostic
Table – Slow
Cranking, Solenoid Clicks or Chatters Go to Step 4
4 Inspect fusible link SBF9, refer to 8A Electrical Body and Chassis.
Is fusible link SBF9 blown? Replace the faulty
fusible link (refer to
Note 3).
If the fusible link
blows again, repair
or replace the circuit from SBF9 to the
starter relay X – 13 pin 1 or ignition
switch B – 62 pin 2 (refer to Note 2) Go to Step 5

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–11

Step Action Yes No
5
Inspect fusible link SBF1, refer to 8A Electrical Body and Chassis.
Is fusible link SBF1 blown? Replace the faulty
fusible link (refer to Note 3).
If the fusible link
blows again, repair
or replace the circuit from SBF1
connection P – 7
and engine
compartment fuse
panel connector B – 63 pin 3, (refer to
Note 2) Go to Step 6
6 Inspect fuse SBF5, refer to 8A Electrical Body and Chassis.
Is fuse SBF5 blown? Replace the faulty
fuse (refer to Note 3).
If the fuse blows again, repair or
replace the circuit from SBF5 to the cabin fuse panel
connector C – 108
pin 2 (refer to Note 2) Go to Step 7
7
Inspect fuse C20, refer to 8A Electrical Body and Chassis.
Is fuse F15 blown? Replace the faulty
fuse (refer to Note 3).
If the fuse blows again, repair or
replace the circuit
from fuse C20 to the ECM connector C –
56 pin 31 (refer to Note 2) Go to Step 8
8 NOTE
On automatic vehicles ensure that park (P) or neutral (N) is
selected.
Turn the headlamps on.
Turn the dome lamps on.
Turn the ignition switch to the START position.
Do the lamps dim? Go to Step 9 Go to Step 10
9
Perform the 3.3 On-Vehicle Testing.
Did you correct the condition?
Go to Step 21 Go to Step 2

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–13

Step Action Yes No
16 1 Scroll to Starter Relay
2 Ensure the transmission is in park (P) or neutral (N).
3 W hile monitoring Tech 2, turn the ignition switch to START.
Does Tech 2 display the following:
Off with the ignition switch in the ON position,
On with the ignition switch in the START position?
Go to Step 18 Go to Step 17
17 1 Disconnect the ECM connector C – 56.
2 Using a multimeter set to measure voltage, back probe between the harness connector C – 56 pin 32 and ground.
3 W ith the aid of an assistant, monitor the voltage on the multimeter.
• Place the transmission in park (P), the multimeter should
display 0 V
• Place the transmission in neutral (N), the multimeter should
display 0 V
Does the multimeter display as described? Refer to 6C1 - 3
Engine
Management – V6 – Service Operations
for further diagnosis.
Go to Step 21 For vehicles fitted
with the 4 speed automatic
transmission refer
to 7C2 Automatic Transmission –
4L60E – On-vehicle Servicing for further
diagnosis of the
park / neutral and back-up switch.

Go to Step 21
18 Test the starter relay.
Refer to 6C1-2 Engine Management – V6 – Diagnostics.
Is the starter relay serviceable? Go to Step 19 Repair or replace
as required
Go to Step 21
19 1 Using a multimeter set to measure voltage, back probe between
the harness connector P – 3 pin 1 and ground.
2 W ith the aid of an assistant, monitor the voltage on the multimeter.
• Turn the ignition switch to START, the multimeter should
display 7.0 V
Does the multimeter display as described? Repair or replace
the starter motor as required.
Refer to 4
Major
Service Operations.
Go to Step 21 Go to Step 20
20 Check for short to ground or open circuit from connector P – 3 pin 1
and the starter relay connector X-13 pin 2.
W as the circuit serviceable? Go to Step 2 Repair as required
(refer to Note 2).
Go to Step 21
21 Operate the system in order to verify the repair.
Did you correct the condition? System OK Go to Step 2
When all diagnosis and repairs are completed, check the system for correct operation.

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ISUZU KB P190 2007

Starting System – V6 Page 6D1-2–16

Engine Compartment Relay And Fuse Panel


Figure 6D1-2 – 4

1 Remove fuses SBF5 and SBF9 from the engine compartment fuse panel to disable the ignition and prevent the engine from starting, refer to 8A Electrical Body and Chassis.
2 Chock the wheels.
3 For vehicles fitted with automatic transmission ensure the transmission is in P (park) or N (neutral) and the hand brake is applied.
4 Ensure the engine is at room temperature or normal operating temperature and in good working order.
Bad Connection Test
A bad connection appears as a voltage reading when the multimeter leads are connected to two different positive (or
negative) connections.
1 Using a multimeter set to measure voltage, connect the multimeter’s positive lead to the positive battery post.
2 Connect the multimeter’s negative lead to the starter motor M terminal.
3 Record the voltage that displayed during cranking.
4 Repeat this with the multimeter’s negative lead connected to the solenoid switch connector P – 4 pin B (circuit 1).
5 Also repeat this connecting the multimeter’s negative lead to the battery cable strands.
6 Restore all connections that show a significant resistance (voltage reading).

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ISUZU KB P190 2007