Isuzu Trooper (1998-2002 year). Manual - part 598

6E–40

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

D

MAP Sensor

D

CMP Sensor

D

CKP Sensor

D

EGR Pressure Sensor

D

EGR VSV 

D

RPCV

D

IAT Sensor

D

Intake Throttle Motor

D

Fuel Temperature Sensor

D

Oil Temperature Sensor

D

Rail Pressure Sensor

Multiple ECM Information Sensor DTCs Set

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Turn the ignition “OFF,” disconnect the ECM.
2. Turn the ignition “ON,” check the 5 volt reference D

circuit for the following conditions:

D

D poor connection at the ECM.

D

An open between the ECM connector and the
splice.

D

D short to ground.

D

D short to voltage.

Is there an open or short?

—

Go to 

Step 3

Go to 

Step 4

3

Repair the open or short.

Is the action complete?

—

Verify repair

—

4

Check the sensor ground circuit for the following
conditions:

D

A poor connection at the ECM or the affected
sensors.

D

An open between the ECM connector and the
affected sensors.

Is there an open or a poor connection?

—

Go to 

Step 5

Go to 

Step 6

5

Repair the open or the poor connection.

Is the action complete?

—

Verify repair

Go to 

Step 6

6

Replace the ECM (Refer to the Data Programming in
Case of ECM change).

Is the action complete?

—

Go to 

OBD

System

Check

—

6E–41

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

EGR (Exhaust Gas Recirculation)

Diagnosis

D

A diagnosis of the EGR system is covered by DTC
P1403.

D

EGR VSV circuit diagnosis is covered by DTC P1404.

D

EGR pressure sensor diagnosis is covered by DTC
P405 and/or P406.

D

EGR EVRV circuit diagnosis is covered by DTC
P1405. Refer to the DTC charts.

Tech 2 Data Definitions and Ranges

A/C CLUTCH–Tech 2 Displays ON or OFF–
Indicates whether the A/C has commanded the A/C
clutch ON.

MAP kPa — Tech 2 Range 10-105 kPa/0.00-5.00
Volts —
The manifold absolute pressure reading is determined
from the MAP sensor signal monitored during key up and
wide open throttle (WOT) conditions.  The manifold
absolute pressure is used to compensate for altitude
differences and is normally displayed around “61-104”
depending on altitude and manifold absolute pressure.

CMP ACT. COUNTER –Cam Position

DESIRED IDLE — Tech 2 Range 0-3187 RPM —
The idle speed that the ECM is commanding.  The ECM
will compensate for various engine loads based on engine
coolant temperature,  to keep the engine at the desired
speed.

ECT — (Engine Coolant Temperature) Tech 2
Range –40

°

C to 151

°

C (–40

°

F to 304

°

F) —

The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the ECM.  The ECM applies 5 volts to the
ECT sensor circuit.  The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the ECM
monitors a high signal voltage and interprets that as a cold
engine.  As the sensor warms (decreasing resistance),
the voltage signal will decrease and the ECM will interpret
the lower voltage as a warm engine.

ENGINE RUN TIME — Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec —
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.

ENGINE SPEED — Range 0-9999 RPM —
Engine speed is computed by the ECM from the 57X
reference input.  It should remain close to desired idle
under various engine loads with engine idling.

Air Intake Valve meter POSITION — Tech 2 Range
0-100 % —

IAT (INTAKE AIR TEMPERATURE)— Tech 2 Range
–40

°

C to 151

°

C (–40

°

F to 304

°

F) —

The ECM converts the resistance of the intake air
temperature sensor to degrees.  Intake air temperature
(IAT) is used by the ECM to adjust fuel delivery and spark
timing according to incoming air density.

MAP — Tech 2 Range 10-105 kPa (0.00-4.97 Volts)—
The manifold absolute pressure (MAP) sensor measures
the change in the boost pressure.

MIL — Tech 2 Displays ON or OFF —
Indicates the ECM commanded state of the malfunction
indicator lamp.

AP — Tech 2 Range 0%-100% —
AP (Accelerator position)  angle is computed by the ECM
from the AP sensor voltage.  AP angle should display
“0%” at idle and “100%” at wide open throttle.

AP SENSOR — Tech 2 Range 0.00-5.00 Volts —
The voltage being monitored by the ECM on the AP
sensor signal circuit.

VEHICLE SPEED—Tech 2 Range 0-255 km/h (0-155
mph)–
The vehicle speed sensor signal is converted into km/h
and mph for display.

Typical Scan Data Values

Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly.  Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing.  The typical scan data values represent
values that would be seen on a normally-running engine.

NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer.  Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.

Only the parameters listed below are referred to in this
service manual for use in diagnosis.  For further
information on using the Tech 2 to diagnose the ECM and
related sensors, refer to the applicable reference section
listed below.  If all values are within the typical range
described below, refer to the 

Symptoms section for

diagnosis.

Test Conditions

Engine running, lower radiator hose hot, transmission in
park or neutral, accessaries off, brake not applied and air
conditioning off.

6E–42

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

4JX1-TC Engine (Automatic and Manual Transmission)

Tech 2

Parameter

Data List

Units

Displayed

Typical Data

Values (IDLE)

Typical Data

Values 

(2500 RPM)

Refer To

Battery Voltage

Engine

Volts

12.5 

∼

 14.5

13 

∼

 15

General Description

Ignition Status

Engine

On/Off

On

On

General Description

Ignition Relay

2

Engine

On/Off

On

On

General Description

Idle Switch

Engine

Inactive/

Active

—

—

DTC P0510, P1510

Manifold
Absolute
Pressure

Engine

KPa

96 

∼

 106

110 

∼

 150

General Description

DTC P0107, P0108

Rail Oil
Pressure

Engine

MPa

3.5 

∼

 5

4.5 

∼

 10

General Description

DTC P0192, P0193

Desired Rail Oil
Pressure

Engine

MPa

4 

∼

 5

5 

∼

 9

General Description

DTC P0192, P0193

Fuel
Temperature

Engine

°

C (

°

F)

75 

∼

 85

75 

∼

 85

DTC P0182, P0183

Quick Warming
Switch

Engine

On/Off

Off

Off

DTC P0380

Thermo Relay

Engine

On/Off

—

—

DTC P1655

Actual EGR
Pressure

Engine

KPa

58 

∼

 60

M/T 63 

∼

 66

A/T 95 

∼

 105

DTC P0405, P0406

Barometric
Pressure

Engine

KPa

98 

∼

 102

98 

∼

 102

General Description

Relative EGR
Pressure

Engine

KPa

–38 

∼

 –45

M/T –34 

∼

 –37

A/T 0

General Description

Desired EGR
Pressure

Engine

KPa

–43 

∼

 –40

M/T 36

A/T 0

General Description

Brake Switch

Engine

Inactive/

Active

—

—

DTC P1588

Gear

Engine

—

—

—

—

Vehicle Speed

Engine

Km/h

0

0

Transmission Diagnosis

Rail Pressure
Control Valve

Engine

%

17 

∼

 22

18 

∼

 27

DTC P1193

EGR Status

Engine

Disable/

Enable

Enable

M/T Enable

A/T Disable

General Description

EGR Switching
Valve

Engine

On/Off

—

—

General Description

Throttle Motor
Position Sensor

Engine

Volts

3.1 

∼

 3.9

0.2 

∼

 0.9

DTC P1485, P1486,
P1487

Throttle Motor
Position

Engine

Steps

0 

∼

 1.0

0 

∼

 1.0

DTC P1488

Delirered Fuel
Quantity

Engine

mm 3/st

6 

∼

 10

6 

∼

 12

General Description

Injector Status

Engine

Disable/

Enable

Enable

Enable

DTC P0201, P0202,
P0203, P0204, General
Description

Injector Pulse
Width

Engine

ms

0.9 

∼

 1.25

0.7 

∼

 1.1

General Description

Injector Start
Offset

Engine

°

CA

—

—

General Description

6E–43

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Tech 2

Parameter

Data List

Units

Displayed

Typical Data

Values (IDLE)

Typical Data

Values 

(2500 RPM)

Refer To

Exhaust VSV1

Engine

On/Off

Off

Off

DTC P0475

Exhaust VSV2

Engine

On/Off

Off

Off

DTC P1475

Decelevation
Fuel Cut Off

Engine

Inactive/

Active

—

—

General Description

Glow Time
Lamp

Engine

On/Off

Off

Off

DTC P0381

Glow Time
Relay

Engine

On/Off

Off

Off

DTC P0380

Diagnostic
Request

Engine

Inactive

12V/

Active 0V

—

—

General Description

A/C Clutch

Engine

On/Off

Off

Off

General Description

Desired Idle

Engine

RPM

720

—

General Description

ECT (Engine
Coolant Temp)

Engine

°

C (

°

F)

80 

∼

 90

80 

∼

 90

General Description

ECT

Engine Speed

Engine

RPM

720

2500

DTC P0219

MAT (Intake Air
Temp)

Engine

°

C (

°

F)

65 

∼

 80

65 

∼

 80

DTC P0112, P0113

MAP KPa
(Manifold
Absolute
Pressure)

Engine

Kilopascals

—

—

General Description

DTC P0107, P0108

MIL

Engine

On/Off

Off

Off

General Description

AP (Accel
Position)

Engine

Percent

0

8 

∼

14

DTC P0121, P0122,
P0123

AP (Accel
Position)

Engine

Volts

0.25 

∼

 0.45

0.8 

∼

 1.0

DTC P0121, P0122,
P0123

Rail Oil
Temperature

Engine

°

C (

°

F)

—

—

DTC P0197, P0198

Desired Throttle
Motor Position

Engine

Steps

—

—

—

Learned Idle
Fuel Quantity

Engine

mm 3/st

—

—

—