1998 ISUZU TROOPER electrical system

6E±296
ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor (KS)
Removal Procedure
1. Disconnect the negative battery cable.
2. Drain the cooling system. Refer to
Draining and
Filling the Cooling System
in Engine Cooling.
3. Remove the engine cover.
4. Remove the common chamber assembly.
Refer to Common Chamber in Engine Mechanical.
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5. Disconnect the electrical connector from the knock
sensor.
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6. Unscrew the knock sensor from the engine block.
Installation Procedure
NOTE: Do not apply thread sealant to the sensor threads.
The sensor is coated at the factory and applying
additional sealant will affect the sensor's ability to detect
detonation.
1. Screw the knock sensor into the engine block.
Tighten

Tighten the knock sensor to 20 N´m (177 lb in.).
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2. Connect the electrical connector to the knock sensor.
3. Install the common chamber assembly.
Refer to Common Chamber in Engine Mechanical.
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4. Install the engine cover.
5. Fill the cooling system.
Refer to Draining and Filling the Cooling System in
Engine Cooling.
6. Connect the negative battery cable.

6E±298
ENGINE DRIVEABILITY AND EMISSIONS
4. Remove the MAP sensor from the mounting bracket.
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Installation Procedure
1. Install the MAP sensor in the mounting bracket.
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2. Install the mounting bracket retaining bolt on the
common chamber.
3. Connect the MAP electrical connector.
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4. Connect the negative battery cable.
Malfunction Indicator Lamp
(MIL)
Removal and Installation Procedure
Refer to Warning light bulb, indicator light valve,
illumination light bulb, A/T indicator light bulb in Meter and
Gauge.
Powertrain Control Module
(PCM)
Service Precaution
NOTE: To p r e ve n t p ossible electrostatic discharge
damage to the PCM, do not touch the connector pins or
soldered components on the circuit board.
Electrostatic Discharge (ESD)
Damage
Electronic components used in the control systems are
often designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4,000
volts for a person to even feel the zap of a static
discharge.
There are several ways for a person to become statically
charged. The most common methods of charging are by
friction and by induction. An example of charging by
friction is a person sliding across a car seat.
Charging by induction occurs when a person with well
insulated shoes stands near a highly charged object and
momentarily touches ground. Charges of the same
polarity are drained off leaving the person highly charged
with the opposite polarity. Static charges can cause

6E±300
ENGINE DRIVEABILITY AND EMISSIONS
4. Disconnect the red, white, and blue electrical
connectors at the PCM.
5. Remove the two screws in the front of the PCM.
6. Remove the one screw at the left rear of the PCM.
7. Pull the PCM straight out from the dashboard.
TS23757
Installation Procedure
1. Insert the PCM into the dashboard.

Line up the holes in front for the mounting screws.
2. Install the PCM with two screws in the front and one
screw at the left rear.
3. Plug the red, white, and blue connectors into the
appropriate sockets.
TS23757
EEPROM
General Description
The Electronically Erasable Programmable Read Only
Memory (EEPROM) is a permanent memory that is
physically soldered within the PCM. The EEPROM
contains program and calibration information that the
PCM needs to control powertrain operation.
EEPROM Programming
1. Step-up ± Ensure that the following conditions have
been met:

The battery is fully charged.

The ignition is ªON.º

The Vehicle Interface Module cable connection at
the DLC is secure.
2. Program the PCM using the latest software matching
the vehicle. Refer to up-to-date Techline equipment
user's instructions.
3. If the PCM fails to program, Refer to
UBS 98 model
year Immobilizer Workshop Manual.
Functional Check
1. Perform the On-Board Diagnostic System Check.
2. Start the engine and run for one minute.
3. Scan for DTCs using the Tech 2.
Power Steering Pressure (PSP)
Switch
General Description
The Power Steering Pressure (PSP) switch closes when
the hydraulic pressure reaches 3920 + 690 kPa (570 +
100 psi). This causes the PCM to actuate the idle air
control valve in order to prevent the additional load from
slowing down the engine. The switch opens when the
hydraulic pressure drops to 2970 + 560 kPa (430 + 80
psi).
Removal Procedure
1. Disconnect the PSP switch pigtail from the wiring
harness.

The pigtail is permanently attached to the switch.
Do not attempt to remove the wires from the
sensor.

Have a container ready to catch the power steering
fluid that leaks out of the line when the switch is
removed.

6E±301 ENGINE DRIVEABILITY AND EMISSIONS
2. Remove the PSP switch from the power steering line.

Plug the line to prevent excessive loss of fluid and
possible contamination of the power steering
system.
TS23760
Installation Procedure
1. Install the PSP switch in the power steering line.
TS23760
2. Connect the PSP switch pigtail to the wiring harness.
3. Check the power steering fluid level. Refer to
Power
Steering
.
4. Start the engine. Watch the PSP switch for signs of
fluid leakage.
Throttle Position (TP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the TPS electrical connector.3. Remove the bolts and the TP sensor from the throttle
body.
TS23747
NOTE: Do not clean the TP sensor by soaking it in
solvent. The sensor will be damaged as a result.
Function Check
Use a Tech 2 to check the TP sensor output voltage at
closed throttle.

The voltage should be under 0.85 volt.

If the reading is greater than 0.85 volt, check the
throttle shaft to see if it is binding. Check that the
throttle cable is properly adjusted, also. Refer to
Throttle Cable Adjustment.

If the throttle shaft is not binding and the throttle cable
is properly adjusted, install a new TP sensor.
Installation Procedure
1. Install the TP sensor on the throttle body with the
bolts.
TS23747

6E±323 ENGINE DRIVEABILITY AND EMISSIONS
11. Connect the fuel filler fuse at the tank.
12. Connect the air breather hose at the tank.
TS23796
13. Fill the fuel tank with fuel.
14. Tighten the fuel filler cap.
15. Connect the negative battery cable.
Throttle Body (TB)
Removal Procedure
1. Disconnect the negative battery cable.
2. Drain the cooling system. Refer to
Cooling System.
3. Remove the accelerator cable assembly. Refer to
Accelerator Cable in Engine Speed Control System..
4. Disconnect the electrical connectors:

Throttle position (TP) sensor.

Idle air control (IAC) solenoid.

Intake air temperature (IAT) sensor. Refer to
Intake Air Temperature Sensor.
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5. Disconnect the vacuum hose below the air horn.
6. Remove the intake air duct clamp.
7. Disconnect the intake air duct.
8. Disconnect the coolant lines from the throttle body.
9. Remove the bolts from the common chamber.
10. Remove the throttle body from the common chamber.
11. Remove the gasket from the upper intake manifold.
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12. Remove the IAC. Refer to Idle Air Control (IAC)
Solenoid
.
13. Remove the TP sensor. Refer to
Throttle Position
(TP) Sensor
.
Inspection Procedure
NOTE: Do not use solvent of any type when you clean the
gasket surfaces on the intake manifold and the throttle
body assembly. The gasket surfaces and the throttle
body assembly may be damaged as a result.

If the throttle body gasket needs to be replaced,
remove any gasket material that may be stuck to the
mating surfaces of the manifold.

Do not leave any scratches in the aluminum casting.
Installation Procedure
1. Install the TP sensor. Refer to Throttle Position (TP)
Sensor
.
2. Install the IAC. Refer to
Idle Air Control (IAC)
Solenoid
.
3. Install the gasket on the common chamber.
4. Install the throttle body on the common chamber.

6E±324
ENGINE DRIVEABILITY AND EMISSIONS
5. Secure the gasket and the throttle body with the four
bolts.

The vacuum lines must be properly routed under
the throttle body before tightening the mounting
bolts.
Tighten

Tighten the throttle body mounting bolts to 24 N´m
(17 lb ft.).
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6. Install the coolant lines.
7. Connect all the vacuum lines.
8. Install the intake air duct.
9. Tighten the intake air duct clamp.
10. Connect all the electrical connectors:

Throttle position (TP) sensor.

Idle air control (IAC) solenoid.

Intake air temperature (IAT) sensor. Refer to
Intake Air Temperature Sensor.
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11. Install the accelerator cable assembly. Refer to
Accelerator Cable in Engine Speed Control System..
12. Fill the cooling system. Refer to
Cooling System.
13. Install the negative battery cable.
Electronic Ignition System
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the electrical connector at the ignition coil.
3. Remove the two screws that secure the ignition coil to
the rocker cover.
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4. Remove the ignition coil and the spark plug boot from
the spark plug.

Twist the ignition coil while pulling it straight up.
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5. Use the spark plug socket in order to remove the
spark plug from the engine.

6E±330
ENGINE DRIVEABILITY AND EMISSIONS
Wiring and Connectors
Wiring Harness Service
The control module harness electrically connects the
control module to the various solenoids, switches and
sensors in the vehicle engine compartment and
passenger compartment.
Replace wire harnesses with the proper part number
replacement.
Because of the low amperage and voltage levels utilized
in powertrain control systems, it is essential that all wiring
in environmentally exposed areas be repaired with crimp
and seal splice sleeves.
The following wire harness repair information is intended
as a general guideline only. Refer to
Chassis Electrical for
all wire harness repair procedures.
Connectors and Terminals
Use care when probing a connector and when replacing
terminals. It is possible to short between opposite
terminals. Damage to components could result. Always
use jumper wires between connectors for circuit
checking. NEVER probe through Weather-Pack seals.
Use an appropriate connector test adapter kit which
contains an assortment of flexible connectors used to
probe terminals during diagnosis. Use an appropriate
fuse remover and test tool for removing a fuse and to
adapt the fuse holder to a meter for diagnosis.
Open circuits are often difficult to locate by sight because
oxidation or terminal misalignment are hidden by the
connectors. Merely wiggling a connector on a sensor, or
in the wiring harness, may temporarily correct the open
circuit. Intermittent problems may also be caused by
oxidized or loose connections.
Be certain of the type of connector/terminal before
making any connector or terminal repair. Weather-Pack
and Com-Pack III terminals look similar, but are serviced
differently.
PCM Connectors and Terminals
Removal Procedure
1. Remove the connector terminal retainer.
2. Push the wire connected to the affected terminal
through the connector face so that the terminal is
exposed.
3. Service the terminal as necessary.
Installation Procedure
1. Bend the tab on the connector to allow the terminal to
be pulled into position within the connector.
2. Pull carefully on the wire to install the connector
terminal retainer.
Wire Harness Repair: Twisted
Shielded Cable
Removal Procedure
1. Remove the outer jacket.
2. Unwrap the aluminum/mylar tape. Do not remove the
mylar.
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3. Untwist the conductors.
4. Strip the insulation as necessary.
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6E±332
ENGINE DRIVEABILITY AND EMISSIONS
2. Cover the splice with tape in order to insulate it from
the other wires.
053
3. Twist the wires as they were before starting this
procedure.
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4. Tape the wires with electrical tape. Hold in place.
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Weather-Pack Connector
Tools Required
J 28742-A Weather-Pack II Terminal Remover
Removal Procedure
A Weather-Pack connector can be identified by a rubber
seal at the rear of the connector. This engine room
connector protects against moisture and dirt, which could
from oxidation and deposits on the terminals. This
protection is important, because of the low voltage and
the low amperage found in the electronic systems.
1. Open the secondary lock hinge on the connector.
070