Isuzu Trooper (1998-2002 year). Manual - part 537

6E–518

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

3. Cut the wire immediately behind the cable seal.

072

Installation Procedure

Make certain the connectors are properly seated and all
of the sealing rings are in place when you reconnect the
leads.  The secondary lock hinge provides a backup
locking feature for the connector.  The secondary lock
hinge is used for added reliability.  This flap should retain
the terminals even if the small terminal lock tangs are not
positioned properly.
Do not replace the Weather-Pack connections with
standard connections.  Read the instructions provided
with the Weather-Pack connector and terminal packages.

1. Replace the terminal.
2. Slip the new seal onto the wire.
3. Strip 5 mm (0.2”) of insulation from the wire.
4. Crimp the terminal over the wire and the seal.

073

5. Push the terminal and the connector to engage the

locking tangs.

070

6. Close the secondary locking hinge.

Com-Pack III

General Information

The Com-Pack III terminal looks similar to some
Weather-Pack terminals.  This terminal is not sealed and
is used where resistance to the environment is not
required.  Use the standard method when repairing a
terminal.  Do not use the Weather-Pack terminal tool J
28742-A or equivalent.  These will damage the terminals.

6E–519

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Metri-Pack

Tools Required

J 35689 Terminal Remover

Removal Procedure

Some connectors use terminals called Metri-Pack Series
150.  These may be used at the engine coolant
temperature (ECT) sensor.

1. Slide the seal (1) back on the wire.
2. Insert the J 35689 tool or equivalent (3) in order to

release the terminal locking tang (2).

060

3. Push the wire and the terminal out through the

connector.  If you reuse the terminal, reshape the
locking tang.

Installation Procedure

Metri-Pack terminals are also referred to as “pull-to-seat”
terminals.

1. In order to install a terminal on a wire, the wire must be

inserted through the seal (2) and through the
connector (3).

2. The terminal (1) is then crimped onto the wire.

061

3. Then the terminal is pulled back into the connector to

seat it in place.

6E–520

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

General Description (PCM and
Sensors)

58X Reference PCM Input

The powertrain control module (PCM) uses this signal
from the crankshaft position (CKP) sensor to calculate
engine RPM and crankshaft position at all engine speeds.
The PCM also uses the pulses on this circuit to initiate
injector pulses.  If the PCM receives no pulses on this
circuit, DTC P0337 will set.  The engine will not start and
run without using the 58X reference signal.

A/C Request Signal

This signal tells the PCM when the A/C mode is selected
at the A/C control head.  The PCM uses this to adjust the
idle speed before turning “ON” the A/C clutch.  The A/C
compressor will be inoperative if this signal is not
available to the PCM.
Refer to 

A/C Clutch Circuit Diagnosis section for A/C

wiring diagrams and diagnosis for the A/C electrical
system.

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor provides a signal
used by the powertrain control module (PCM) to calculate
the ignition sequence.  The CKP sensor initiates the 58X
reference pulses which the PCM uses to calculate RPM
and crankshaft position.
Refer to 

Electronic Ignition System section for additional

information.

0013

Engine Coolant Temperature (ECT) Sensor

The engine coolant temperature (ECT) sensor is a
thermistor (a resistor which changes value based on
temperature) mounted in the engine coolant stream.  Low
coolant temperature produces a high resistance of
100,000 ohms at –40

°

C (–40

°

F).  High temperature

causes a low resistance of 70 ohms at 130

°

C (266

°

F).

The PCM supplies a 5-volt signal to the ECT sensor
through  resistors in the PCM and measures the voltage.
The signal voltage will be high when the engine is cold and
low when the engine is hot.  By measuring the voltage, the

PCM calculates the engine coolant temperature.  Engine
coolant temperature affects most of the systems that the
PCM controls.
The Tech 2 displays engine coolant temperature in
degrees.  After engine start-up, the temperature should
rise steadily to about 85

°

C (185

°

F).  It then stabilizes

when the thermostat opens.  If the engine has not been
run for several hours (overnight), the engine coolant
temperature and intake air temperature displays should
be close to each other.  A hard fault in the engine coolant
sensor circuit will set DTC P0177 or DTC P0118.  An
intermittent fault will set a DTC P1114 or P1115.

0016

Electrically Erasable Programmable Read
Only Memory (EEPROM)

The electrically erasable programmable read only
memory (EEPROM) is a permanent memory chip that is
physically soldered within the PCM.  The EEPROM
contains the program and the calibration information that
the PCM needs to control powertrain operation.
Unlike the PROM used in past applications, the EEPROM
is not replaceable.  If the PCM is replaced, the new PCM
will need to be programmed.  Equipment containing the
correct program and calibration for the vehicle is required
to program the PCM.

Fuel Control Heated Oxygen Sensors

The fuel control heated oxygen sensors (Bank 1 HO2S 1
and Bank 2 HO2S 1) are mounted in the exhaust stream
where they can monitor the oxygen content of the exhaust
gas.  The oxygen present in the exhaust gas reacts with
the sensor to produce a voltage output.  This voltage
should constantly fluctuate from approximately 100 mV to
900 mV.  The heated oxygen sensor voltage can be
monitored with a Tech 2.  By monitoring the voltage output
of the oxygen sensor, the PCM calculates the pulse width
command for the injectors to produce the proper
combustion chamber mixture.

D

Low HO2S voltage is a lean mixture which will result in
a rich command to compensate.

D

High HO2S voltage is a rich mixture which will result in
a lean command to compensate.

6E–521

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

An open Bank 1 HO2S 1 signal circuit will set a DTC
P0134 and the Tech 2 will display a constant voltage
between 400-500 mV.  A constant voltage below 300 mV
in the sensor circuit (circuit grounded) will set DTC
P0131.  A constant voltage above 800 mV in the circuit will
set DTC P0132.  Faults in the Bank 2 HO2S 1 signal
circuit will cause DTC 0154 (open circuit), DTC P0151
(grounded circuit), or DTC P0152 (signal voltage high) to
set.  A fault in the Bank 1 HO2S 1 heater circuit will cause
DTC P0135 to set.  A fault in the Bank 2 HO2S 1 heater
circuit will cause DTC P0155 to set.  The PCM can also
detect HO2S response problems.  If the response time of
an HO2S is determined to be too slow, the PCM will store
a DTC that indicates degraded HO2S performance.

060RY00127

Catalyst Monitor Heated Oxygen Sensors 

Three-way catalytic converters are used to control
emissions of hydrocarbons (HC), carbon monoxide (CO),
and oxides of nitrogen (NOx).  The catalyst within the
converters promotes a chemical reaction.  This reaction
oxidizes the HC and CO present in the exhaust gas and
converts them into harmless water vapor and carbon
dioxide.  The catalyst also reduces NOx by converting it to
nitrogen.  The PCM can monitor this process using the
Bank 1 HO2S 2 and the Bank 2 HO2S 2 heated oxygen
sensors.  The Bank 1 HO2S 1 and the Bank 2 HO2S 1
sensors produce an output signal which indicates the
amount of oxygen present in the exhaust gas entering the
three-way catalytic converter.   The Bank 1 HO2S 2 and
the Bank 2 HO2S 2 sensors produce an output signal
which indicates the oxygen storage capacity of the
catalyst.  This indicates the catalyst’s ability to efficiently
convert exhaust gases.  If the catalyst is operating
efficiently,  the Bank 1 HO2S 1 and the Bank 2 HO2S 1
signals will be more active than the signals produced by
the Bank 1 HO2S 2 and the Bank 2 HO2S 2 sensors.
The catalyst monitor sensors operate the same as the
fuel control sensors.  The Bank 1 HO2S 2 and the Bank 2
HO2S 2 sensors’ main function is catalyst monitoring, but
they also have a limited role in fuel control.  If a sensor
output indicates a voltage either above or below the 450
mV bias voltage for an extended period of time, the PCM

will make a slight adjustment to fuel trim to ensure that
fuel delivery is correct for catalyst monitoring.
A problem with the Bank 1 HO2S 2 signal circuit will set
DTC P0137, P0138, or P0140, depending on the specific
condition.  A problem with the Bank 2 HO2S 2 signal
circuit will set DTC P0157, P0158, or P0160, depending
on the specific condition.  A fault in the heated oxygen
sensor heater element or its ignition feed or ground will
result in lower sensor response.  This may cause
incorrect catalyst monitor diagnostic results.

TS24067

TS23365A

Legend

(1) Bank 1 Sensor 1 (Fuel Control)
(2) Catalytic Converter
(3) Bank 1 Sensor 2 (Catalyst Monitor)
(4) Bank 2 Sensor 1 (Fuel Control)
(5) Bank 2 Sensor 2 (Catalyst Monitor)

Intake Air Temperature (IAT) Sensor

The intake air temperature (IAT) sensor is a thermistor
which changes its resistance based on the temperature of
air entering the engine.  Low temperature produces a high