Pin IAT sensor ISUZU TROOPER 1998 Service Owner's Guide

6E±25 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
Serviceability Issues
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Accordingly, if commercially sold sensor
or switch is installed, it makes a wrong diagnosis and turn
on the MIL (ªCheck Engineº lamp).
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (ªCheck
Engineº lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted oil filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a ªnon-vehicle
faultº, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD system diagnostics will not run if the
ECM detects a fault on a related system or component.
Visual/Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:

Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.

Inspect hoses that are difficult to see behind other
components.

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the ªClass IIº communication system.
Each bit of information can have one of two lengths: longor short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait.
On this vehicle the Tech 2 displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The diagnostic test has passed during the current
ignition cycle.

The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The fault identified by the diagnostic test is currently
active.

The fault has been active during this ignition cycle.

The operating conditions at the time of the failure.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to operate engine properly.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable. Accel
Position (AP) sensor that indicates high throttle position
at low engine loads or MAP voltage. Input components
may include, but are not limited to the following sensors:

Intake Air Temperature (IAT) Sensor

Crankshaft Position (CKP) Sensor

Intake throttle Position (ITP) Sensor

Engine Coolant Temperature (ECT) Sensor

Camshaft Position (CMP) Sensor

Manifold absolute Pressure (MAP) Sensor

Accel Position Sensor

Fuel Temp Sensor

Rail Pressure Sensor

Oil Temp Sensor

EGR Pressure Sensor

Vehicle Speed Sensor

6E±131 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1403 ± EGR EVRV Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Check the EVRV circuit.
Was the EVRV circuit darmage?
Ð
Replace the
EVRV circuit
Go to Step 3
31. Start the engine.
2. Monitor the MAP signal with a scan tool while idling.
3. While idling, jab the accelerator pedal about halfway
down and immediately let the engine return to idle.
Did the MAP value on the scan tool show an immediate
large change?
ÐGo to Step 5Go to Step 4
4Replace the MAP sensor.
Is the action complete?
ÐVerify repairÐ
51. Inspect the exhaust system for modification of
original installed parts or leaks.
2. If a problem was found, repair exhaust system as
necessary.
Was a condition present that required repair?
ÐGo to Step 8Go to Step 6
61. Remove the EGR valve.
2. Visually and physically inspect the pintle, valve
passages and the adapter for excessive deposits or
any kind of a restriction.
3. If a problem is found, clean or replace EGR system
components as necessary.
Was a condition present that required repair?
ÐGo to Step 8Go to Step 7
71. Inspect the EGR passages for a blockage caused
by excessive deposits or other damage.
2. If a problem is found, correct the condition as
necessary.
Was a condition present that required repair?
ÐGo to Step 8
Refer to
Diagnostic
Aids
81. Review and record the scan tool Failure Records
data.
2. Clear DTC and monitor the scan tool System Info
Screen while operating the vehicle as specified in
ªDiagnostic Aids.º
3. Using a scan tool, monitor ªDTCº info for DTC
P1403 until the DTC P1403 test runs.
4. Note the test result.
Does the scan tool indicate DTC P1403 failed this
ignition?
Ð
Go to the last
step
completed in
this
diagnostic
chart
Repair
complete

6E±176
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Symptom Diagnosis
Preliminary Checks
Before using this section, perform the ªOn±Board
Diagnostic (OBD) System Checkº and verify all of the
following items:

The powertrain control module (ECM) and
malfunction indicator lamp (MIL) (CHECK ENGINE
lamp) are operating correctly.

There are no DTC(s) stored.

Tech±2 data is within normal operating range. Refer
to
Typical Scan Data Values.

Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
Visual/Physical Check
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time.
This check should include the following items:

ECM grounds for cleanliness, tightness and proper
location.

Vacuum hoses for splits, kinks, and proper
connections, as shown on the ªVehicle Emission
Control Informationº label. Check thoroughly for any
type of leak or restriction.

Air intake ducts for collapsed or damaged areas.

Injector wires for cracking, hardness, and carbon
tracking.

Wiring for proper connections, pinches and cuts.
Intermittents
IMPORTANT:An intermittent problem may or may not
turn on the malfunction indicator lamp (MIL) or store a
DTC. DO NOT use the Diagnostic Trouble Code (DTC)
charts for intermittent problems. The fault must be
present to locate the problem.
Most intermittent problems are caused by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions:

Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).

Improperly formed or damaged terminal.

All connector terminals in the problem circuit should
be carefully checked for proper contact tension.

Poor terminal±to±wire connection. This requires
removing the terminal from the connector body to
check.
Road test the vehicle with a Digital Multimeter
(5-8840-0285-0) connected to a suspected circuit. An
abnormal voltage when the malfunction occurs is a good
indication that there is a fault in the circuit being
monitored.
Use a scan tool to help detect intermittent conditions. The
scan tools have several features that can be used to
locate an intermittent condition. Use the following feature
to find intermittent faults:
Using a Tech±2 ªFreeze Frameº buffer or ªFailure
Recordsº buffer can aid in locating an intermittent
condition. Review and record the information in the
freeze frame or failure record associated with the
intermittent DTC being diagnosed. The vehicle can
be driven within the conditions that were present
when the DTC originally set.
To check for loss of diagnostic code memory, disconnect
the MAP sensor and idle the engine until the MIL (CHECK
ENGINE lamp) comes on. DTC P0107 should be stored
and kept in memory when the ignition is turned ªOFF.º If
not, the ECM is faulty. When this test is completed, make
sure that you clear the DTC P0107 from memory.
An intermittent MIL (CHECK ENGINE lamp) with no
stored DTC may be caused by the following:

MIL (CHECK ENGINE lamp) wire to ECM shorted to
ground.

Poor ECM grounds. Refer to the ECM wiring
diagrams.
Check for improper installation of electrical options such
as lights, cellular phones, etc.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in
Electrical Diagnosis).
If problem has not been found, refer to
ECM Connector
Symptom
tables.

6E±227 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS

QOS

Diagnostics
± Malfunction Indicator Lamp (Service Engine
Soon lamp)
± Data Link Connector (DLC)
± Data Output
ECM Service Precautions
The ECM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the ECM's circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter. The ECM should remain
connected to the ECM or to a recommended breakout
box.
Intake Throttle Position (ITP) Sensor
ITP sensor is a potentiometer type and installed to the
intake throttle valve body. A voltage of 5V is applied
constantly from ECM to ITP sensor thereby to determine
by change in voltage the opening of the intake throttle
valve during warming up.
Transmission Range Switch
IMPORTANT:The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the ECM which position is selected by the
transmission selector lever.
For more information on the transmission on the
transmission range switch, refer to
Automatic
Transmission
.
Accelerator Position Sensor (AP)
AP sensor is a potentiometer type and installed to
accelerator pedal bracket. A voltage of 5V constantly
applied from ECM to the sensor thereby to determine the
accelerator pedaling angle by change in voltage. Further,
this sensor is provided with an accelerator switch, which
is set off only when the accelerator pedal is stepped on.
Aftermarket Electrical and Vacuum
Equipment
Aftermarket (add-on) electrical and vacuum equipment is
defined as any equipment which connects to the vehicle's
electrical or vacuum systems that is installed on a vehicle
after it leaves the factory. No allowances have been
made in the vehicle design for this type of equipment.
NOTE: No add-on vacuum equipment should be added
to this vehicle.
NOTE: A d d - o n e l e c t r i c a l equipment must only be
connected to the vehicle's electrical system at the battery
(power and ground).
Add-on electrical equipment, even when installed to
these guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such asportable telephones and radios. Therefore, the first step
in diagnosing any powertrain problem is to eliminate all
aftermarket electrical equipment from the vehicle. After
this is done, if the problem still exists, it may be diagnosed
in the normal manner.
Electrostatic Discharge Damage
Electronic components used in the ECM 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 4000
volts for a person to feel even the zap of a static
discharge.
TS23793
There are several ways for a person to become statically
charged. The most common methods of charging are by
friction and induction.

An example of charging by friction is a person sliding
across a vehicle seat.

Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground. Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity. Static
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.
NOTE: To p r e ve n t p ossible electrostatic discharge
damage, follow these guidelines:

Do not touch the ECM connector pins or soldered
components on the ECM circuit board.

Do not open the replacement part package until the
part is ready to be installed.

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

If the part has been handled while sliding across the
seat, while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±21
NOTE: To use the DTC again to identify a problem, you
will need to reproduce the fault or the problem. This may
require a new test drive or just turning the ignition on (this
depends on the nature of the fault).
1. IF you have a Tech2:
1. Connect the Tech2 if it is still not connected
GOTHROUGH Tech2 OBD II CONNECTION.
2. Push ªF4º and answer ªYesº to the question ªDo
you really want to clear the codes?º
a. When a malfunction remains as it is the Tech2
displays ª4L30E CODES NOT CLEAREDº. This
means that the problem is still there or that the
recovery was not done. Please GOTO DTC
CHECK.
b. When a malfunction has been repaired and the
recovery is done. The Tech2 displays ª4L30E
CODES CLEAREDº.
2. IF you have no Tech2:
To clear the DTC, remove Fuse ªStop, A/T CONTº
(C±14, 15A) for at least 10 seconds.
DTC Check
1. Diagnostic Trouble Codes (DTC) have been identified
by Tech2.
2. You have written the list of the DTCs. The order of the
malfunctions has no meanings for this PCM. Usually
only one or two malfunctions should be set for a given
problem.
3. Check directly the DTCs you identified. The DTCs are
sorted by number. Refer to Diagnostic Trouble Code
(DTC) Identification in this section.
PCM Precaution
The PCM can be damaged by:
1. Electrostatic discharge
2. The short circuit of some terminals to voltage or to
ground.
Electrostatic Discharge Damage Description:
1. Electronic components used to control systems are
often designed to carry very low voltage, and are very
susceptible to damage caused by electrostatic
discharge. It is possible for less than 100 volts of
static electricity to 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.2. There are several ways for a person to become
statically charged. The most common methods of
charging are by friction and induction. An example of
charging by friction is a person sliding across a car
seat, in which a charge of as much as 25,000 volts
can build up. Charging by induction occurs when a
person with well insulated shoes stands near a highly
charged object and momentarily touches ground.
Charges for the same polarity are drained off, leaving
the person highly charged with the opposite polarity.
Static charges of either type can cause damage,
therefore, it is important to use care when handling
and testing electronic components.
NOTICE: To prevent possible electrostatic
discharge damage:
1. Do not touch the PCM connector pins or soldered
components on the PCM circuit board.
2. Be sure to follow the guidelines listed below if
servicing any of these electronic components:
3. Do not open the replacement part package until it is
time to install the part.
4. Avoid touching electrical terminals of the part.
5. Before removing the part from its package, ground
the package to a known good ground on the vehicle.
6. Always touch a known good ground before handling
the part. This step should be repeated before
installing the part if the part has been handled while
sliding across the seat, while sitting down from a
standing position or while walking some distance.
Information On PCM
1. The Powertrain Control Module (PCM) is located in
the center console and is the control center of the
electronic transmission control system.
2. The PCM must be maintained at a temperature below
185
F (85
C) at all times. This is most essential if the
vehicle is put through a paint baking process. The
PCM will become inoperative if its temperature
exceeds 85
C (185
F). Therefore, it is
recommended that the PCM be removed or that
temporary insulation be placed around the PCM
during the time the vehicle is in a paint oven or other
high temperature process.
3. The PCM is designed to process the various inputs
and then respond by sending the appropriate
electrical signals to control transmission upshift,
downshift, shift feel and torque converter clutch
engagement.
4. The PCM constantly interprets information from the
various sensors, and controls the systems that affect
transmission and vehicle performance. By analyzing
operational problems, the PCM is able to perform a
diagnostic function by displaying DTC(s) and aid the
technician in making repairs.
Intermittent Conditions
If the Tech2 displays a diagnostic trouble code as
intermittent, or if after a test drive a DTC does not
reappear though the detection conditions for this DTC are
present, the problem is most likely a faulty electrical

SUPPLEMENTAL RESTRAINT SYSTEM 9J±12
Deployed Air Bag Assembly (Driver Side)
ªYou should wear gloves and glasses. After the air bag
assembly has been deployed, the surface of the air bag
may contain solid particulate. This solid particulate
consists primarily of by products of the chemical reaction,
Potassium Chloride and copper metal dust. Compounds
of Potassium Borate, Strontium Chloride, Copper
Chloride, and Ammonium Chloride may be found in
amounts of about 1% (each) of the total particulate.º
Deployed Pretensioner Seat Belt.
You should wear gloves and safety glasses. After the
pretensioner seat belt has been deployed, the surface of
the pretensioner seat belt cylinder may heating up.
Air Bag Assembly and/or Pretensioner
Seat Belt Scrapping Procedure.
During the cause of vehicle's useful life, certain situations
may arise which will necessitate the disposal of a live air
bag and/or pretensioner seat belt. (This information
covers proper procedures for disposing of a live air bag
assembly and/or pretensioner seat belt.)
Before a live air bag assembly can be dispose off, it must
be deployed.
A live air bag assembly and/or pretensioner seat belt
must not be disposed of though normal refuse channels.
WARNING: FA I L U R E T O F O L L O W P R O P E R
SUPPLEMENTAL RESTRAINT SYSTEM (SRS) AIR
BAG ASSEMBLY DISPOSAL PROCEDURES CAN
RESULT IN AIR BAG DEPLOYMENT WHICH MAY
CAUSE PERSONAL INJURY. AN UNDPLOYED AIR
BAG ASSEMBLY MUST NOT BE DISPOSED OF
THROUGH NORMAL REFUSE CHANNELS. THE
UNDEPLOYED AIR BAG ASSEMBLY CONTAINS
SUBSTANCES THAT CAN CAUSE SEVERE ILLNESS
OR PERSONAL INJURY IF THE SEALED CONTAINER
IS DAMAGED DURING DISPOSAL. DISPOSAL IN
ANY MANNER INCONSISTENT WITH PROPER
PROCEDURES MAY BE A VIOLATION OF LOCAL
LAW.
In situations which require deployment of a live air bag
assembly, deployment may be accomplished inside or
outside the vehicle. The method employed depends
upon the final disposition of the particular vehicle, as
noted in ªDeployment Outside Vehicleº and ªDeployment
Inside Vehicleº in this section.
Cautions About Air Bag Deployment And
Disposal
Failure to follow proper procedures could result in
erroneous air bag deployment which may cause personal
injury be sure to follow proper procedures.
1. Turn off (Lock) the ignition switch and disconnect the
minus terminal of the battery, then start the work 15 or
more sec later. (Air bag is designed to work by the
back-up power source even if the battery power
source is cut off at vehicle collision).
2. Be sure not to disassemble the air bag.
3. Do not give an impact to the air bag and bring the air
bag close to magnet. (The air bag could deploy
unexpectedly).4. Place the air bag with its trim cover up.
5. Do not let the air bag deploy directly on the floor. (The
air bag may be blown off 2 ~ 3 m (6.5 or 10 feet)).
6. Be sure to install the air bag firmly to a deployment
tool (fixing tool).
7. Set a battery 10 m (33 feet) or more away from the air
bag.
8. Before disconnecting air bag harness, ground the
worker by touching the vehicle outer panel with bare
hand.
9. When connecting or disconnecting the harness, do
not work just in front of the air bag.
10. As deployment gives rise to big sound, warn the
people around against it. Further, try to reduce the
sound by covering the steering wheel or tires, and
shut the vehicle windows in case of deployment
inside the vehicle.
11. As deployment generates smoke, select a well
ventilated place. (In case of deployment indoors,
avoid deployment just under a fire alarm, smoke
sensor, and fluorescent lamps).
12. Be careful not to inhale the smoke after deployment.
13. If part of the vehicle glass is damaged, cover the
vehicle with a car cover to prevent the glass from
braking at the time of deployment.
14. Do not touch the air bag immediately after
deployment, since it remains hot for 30 minutes.
15. Do not water the air bag immediately after
deployment.
16. Wear safety glasses and gloves throughout the work
and wash the glasses and gloves after the work.
17. Do not reuse the removed air bag for another vehicle.
(Deployment characteristic is different with vehicle
types).
Deployment Outside Vehicle (Driver Air
Bag Assembly)
Deployment outside the vehicle is proper when the
vehicle is to be returned to service. This includes, for
example, situations in which the vehicle will be returned to
useful service after a functionally or cosmetically deficient
air bag assembly is replaced. Deployment and disposal
of a malfunctioning air bag assembly is, of course, subject
to any required retention period.
For deployment of a live (undeployed) air bag assembly
outside the vehicle, the deployment procedure must be
followed exactly. Always wear safety glasses during this
deployment procedure until a deployed air bag assembly
is scrapped or until an undeployed air bag assembly is
shipped. Before performing the procedures you should
be familiar with servicing the SRS and with proper
handling of the air bag assembly. Procedures should be
read fully before they are performed.
The following procedure requires use of 5±8840±2468±0
SRS deployment harness with appropriate pigtail
adapter. Do not attempt procedure without
5±8840±2468±0 adapter.
WARNING: FAILURE TO FOLLOW PROCEDURES IN
THE ORDER LISTED MAY RESULT IN PERSONAL
INJURY. NEVER CONNECT DEPLOYMENT