2002 ISUZU AXIOM engine coolant

6E±576
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostics
± Malfunction Indicator Lamp
± Data Link Connector (DLC)
± Data Output

Transmission Control Module
PCM Service Precautions
The PCM 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 PCM's circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter J 39200. The PCM should remain
connected to the PCM or to a recommended breakout
box.
Reprogramming The PCM
Reprogramming of the PCM is done without removing it
from the vehicle . This provides a flexible and
cost-effective method of making changes in software
calibrations.
Refer to the latest Techline information on
reprogramming or flashing procedures.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer
connected to the throttle shaft on the throttle body. The
PCM monitors the voltage on the signal line and
calculates throttle position. As the throttle valve angle is
changed (accelerator pedal moved), the TP sensor signal
also changes. At a closed throttle position, the output of
the TP1 sensor is low. As the throttle valve opens, the
output increases so that at wide open throttle (WOT), the
output voltage should be above 92% (Tech 2 Display).
The PCM calculates fuel delivery based on throttle valve
angle (driver demand). A broken or loose TP sensor may
cause intermittent bursts of fuel from an injector and
unstable idle because the PCM thinks the throttle is
moving.
060RY00027
Transmission Fluid Temperature (TFT)
Sensor
The transmission fluid temperature sensor is a thermistor
which changes its resistance based on the temperature of
the transmission fluid. For a complete description of the
TFT sensor, refer to
4L30-E Automatic Transmission
Diagnosis
section.
A failure in the TFT sensor or associated wiring will cause
DTC P0712 or DTC P0713 to set. In this case, engine
coolant temperature will be substituted for the TFT
sensor value and the transmission will operate normally.
Transmission Range Switch (Mode 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 PCM which position is selected by the
transmission selector lever. This information is used for
ignition timing, EVAP canister purge, EGR operation.
For more information on the transmission on the
transmission range switch, refer to
4L30-E Automatic
Transmission
section.
Vehicle Speed Sensor (VSS)
The PCM determines the speed of the vehicle by
converting a pulsing voltage signal from the vehicle speed
sensor (VSS) into miles per hour. The PCM uses this
signal to operate the cruise control, speedometer, and the
TCC and shift solenoids in the transmission. For more
information on the TCC and shift solenoids, refer to
4L30-E Automatic Transmission section.
0008
Use of Circuit Testing Tools
Do not use a test light to diagnose the powertrain
electrical systems unless specifically instructed by the
diagnostic procedures. Use Connector Test Adapter Kit J
35616 whenever diagnostic procedures call for probing
connectors.

6E±579
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
The PCM monitors signals from several sensors in order
to determine the fuel needs of the engine. Fuel is
delivered under one of several conditions called ªmodes.º
All modes are controlled by the PCM.
Fuel Pressure Regulator
The fuel pressure regulator is a diaphragm-operated
relief valve mounted on the fuel rail with fuel pump
pressure on one side and manifold pressure on the other
side. The fuel pressure regulator maintains the fuel
pressure available to the injector at three times
barometric pressure adjusted for engine load. It may be
serviced separtely.
If the pressure is too low, poor performance and a DTC
P0131, DTC P0151,DTC P0171 or DTC P1171 will be the
result. If the pressure is too high, excessive odor and/or a
DTC P0132, DTC P0152,DTC P0172 will be the result.
Refer to
Fuel System Diagnosis for information on
diagnosing fuel pressure conditions.
014RY00010
Fuel Pump Electrical Circuit
When the key is first turned ªON,º the PCM energizes the
fuel pump relay for two seconds to build up the fuel
pressure quickly. If the engine is not started within two
seconds, the PCM shuts the fuel pump off and waits until
the engine is cranked. When the engine is cranked and
the 58 X crankshaft position signal has been detected by
the PCM, the PCM supplies 12 volts to the fuel pump relay
to energize the electric in-tank fuel pump.
An inoperative fuel pump will cause a ªno-startº condition.
A fuel pump which does not provide enough pressure will
result in poor performance.
Fuel Rail
The fuel rail is mounted to the top of the engine and
distributes fuel to the individual injectors. Fuel is
delivered to the fuel inlet tube of the fuel rail by the fuel
lines. The fuel goes through the fuel rail to the fuel
pressure regulator. The fuel pressure regulator maintains
a constant fuel pressure at the injectors. Remaining fuel
is then returned to the fuel tank.
055RW009
Run Mode
The run mode has the following two conditions:

Open loop

Closed loop
When the engine is first started the system is in ªopen
loopº operation. In ªopen loop,º the PCM ignores the
signal from the heated oxygen sensor (HO2S). It
calculates the air/fuel ratio based on inputs from the TP,
ECT, and MAF sensors.
The system remains in ªopen loopº until the following
conditions are met:

The HO2S has a varying voltage output showing that
it is hot enough to operate properly (this depends on
temperature).

The ECT has reached a specified temperature.

A specific amount of time has elapsed since starting
the engine.

Engine speed has been greater than a specified RPM
since start-up.
The specific values for the above conditions vary with
different engines and are stored in the programmable
read only memory (PROM). When these conditions are
met, the system enters ªclosed loopº operation. In
ªclosed loop,º the PCM calculates the air/fuel ratio
(injector on-time) based on the signal from the HO2S.
This allows the air/fuel ratio to stay very close to 14.7:1.
Starting Mode
When the ignition is first turned ªON,º the PCM energizes
the fuel pump relay for two seconds to allow the fuel pump
to build up pressure. The PCM then checks the engine
coolant temperature (ECT) sensor and the throttle
position (TP) sensor to determine the proper air/fuel ratio
for starting.
The PCM controls the amount of fuel delivered in the
starting mode by adjusting how long the fuel injectors are
energized by pulsing the injectors for very short times.

6E±580
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Throttle Body Unit
The throttle body has a throttle plate to control the amount
of air delivered to the engine. The TP sensor are also
mounted on the throttle body. Vacuum ports located
behind the throttle plate provide the vacuum signals
needed by various components.
Engine coolant is directed through a coolant cavity in the
throttle body to warm the throttle valve and to prevent
icing.
025RY00005
General Description (Electronic
Ignition 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 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.
Electronic Ignition
The electronic ignition system controls fuel combustion
by providing a spark to ignite the compressed air/fuel
mixture at the correct time. To provide optimum engine
performance, fuel economy, and control of exhaust
emissions, the PCM controls the spark advance of the
ignition system. Electronic ignition has the following
advantages over a mechanical distributor system:

No moving parts.

Less maintenance.

Remote mounting capability.

No mechanical load on the engine.

More coil cooldown time between firing events.

Elimination of mechanical timing adjustments.

Increased available ignition coil saturation time.
0013
Ignition Coils
A separate coil-at-plug module is located at each spark
plug. The coil-at-plug module is attached to the engine
with two screws. It is installed directly to the spark plug by
an electrical contact inside a rubber boot. A three-way
connector provides 12-volt primary supply from the
15-amp ignition fuse, a ground-switching trigger line from
the PCM, and a ground.
060RY00022
Ignition Control
The ignition control (IC) spark timing is the PCM's method
of controlling the spark advance and the ignition dwell.
The IC spark advance and the ignition dwell are
calculated by the PCM using the following inputs:

Engine speed.

Crankshaft position (58X reference).

Engine coolant temperature (ECT) sensor.

Throttle position (TP) sensor.

ION sensing module.

Park/Neutral position (PRNDL input).

6E±581
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Vehicle speed (vehicle speed sensor).

PCM and ignition system supply voltage.

The crankshaft position (CKP) sensor sends the PCM
a 58X signal related to the exact position of the
crankshaft.
TS22909Based on these sensor signals and engine load
information, the PCM sends 5V to each ignition coil.
060RY00116This module has the function to energize and de-energize
the primary ignition coil in response to signals from the
PCM. The Throttle PCM controls ignition timing and dwell
time.
Continuity and out-or-range value check:
This diagnosis detects open circuit or short-circuiting in
the Electronic Spark Timing (EST) line by monitoring EST
signals. A failure determination is made when the signal
voltage remains higher or lower than the threshold for
corresponding fault code beyond a predetermined time
period.
Diagnosis enabling conditions are as follows:

RPM is higher than the specified threshold.
EST line is enabled.
060RY00029
Ignition Control PCM Output
The PCM provides a zero volt (actually about 100 mV to
200 mV) or a 5-volt output signal to the ignition control (IC)
module. Each spark plug has its own primary and
secondary ignition coil assembly (ºcoil-at-plugº) located
at the spark plug itself. When the ignition coil receives the
5-volt signal from the PCM, it provides a ground path for
the B+ supply to the primary side of the coil-at -plug
module. When the PCM shuts off the 5-volt signal to the
ION sensing module, the ground path for the primary coil
is broken. The magnetic field collapses and induces a
high voltage secondary impulse which fires the spark plug
and ignites the air/fuel mixture.
The circuit between the PCM and the ignition coil is
monitored for open circuits, shorts to voltage, and shorts
to ground. If the PCM detects one of these events, it will
set one of the following DTCs:

P0351: Ignition coil Fault on Cylinder #1

P0352: Ignition coil Fault on Cylinder #2

P0353: Ignition coil Fault on Cylinder #3

P0354: Ignition coil Fault on Cylinder #4

P0355: Ignition coil Fault on Cylinder #5

P0356: Ignition coil Fault on Cylinder #6
Powertrain Control Module (PCM)
The PCM is responsible for maintaining proper spark and
fuel injection timing for all driving conditions. To provide
optimum driveability and emissions, the PCM monitors
the input signals from the following components in order
to calculate spark timing:

Engine coolant temperature (ECT) sensor.

Intake air temperature (IAT) sensor.

Mass air flow (MAF) sensor.

PRNDL input from transmission range switch.

Throttle position (TP) sensor.

Vehicle speed sensor (VSS) .

6E±583
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
between the seats. In extreme cases, exhaust blow-by
and damage beyond simple gap wear may occur.
Cracked or broken insulators may be the result of
improper installation, damage during spark plug
re-gapping, or heat shock to the insulator material. Upper
insulators can be broken when a poorly fitting tool is used
during installation or removal, when the spark plug is hit
from the outside, or is dropped on a hard surface. Cracks
in the upper insulator may be inside the shell and not
visible. Also, the breakage may not cause problems until
oil or moisture penetrates the crack later.
TS23994
A/C Clutch Diagnosis
A/C Clutch Circuit Operation
A 12-volt signal is supplied to the A/C request input of the
PCM when the A/C is selected through the A/C control
switch.
The A/C compressor clutch relay is controlled through the
PCM. This allows the PCM to modify the idle air control
position prior to the A/C clutch engagement for better idle
quality. If the engine operating conditions are within their
specified calibrated acceptable ranges, the PCM will
enable the A/C compressor relay. This is done by
providing a ground path for the A/C relay coil within the
PCM. When the A/C compressor relay is enabled,
battery voltage is supplied to the compressor clutch coil.
The PCM will enable the A/C compressor clutch
whenever the engine is running and the A/C has been
requested. The PCM will not enable the A/C compressor
clutch if any of the following conditions are met:

The throttle is greater than 90%.

The engine speed is greater than 6315 RPM.

The ECT is greater than 119
C (246
F).

The IAT is less than 5
C (41
F).

The throttle is more than 80% open.
A/C Clutch Circuit Purpose
The A/C compressor operation is controlled by the
powertrain control module (PCM) for the following
reasons:

It improvises idle quality during compressor clutch
engagement.

It improvises wide open throttle (WOT) performance.

It provides A/C compressor protection from operation
with incorrect refrigerant pressures.
The A/C electrical system consists of the following
components:

The A/C control head.

The A/C refrigerant pressure switches.

The A/C compressor clutch.

The A/C compressor clutch relay.

The PCM.
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 A/C electrical system.
General Description (Evaporative
(EVAP) Emission System)
EVAP Emission Control System Purpose
The basic evaporative emission (EVAP) control system
used on all vehicles is the charcoal canister storage
method. Gasoline vapors from the fuel tank flow into the
canister through the inlet labeled ªTANK.º These vapors
are absorbed into the activated carbon (charcoal) storage
device (canister) in order to hold the vapors when the
vehicle is not operating. The canister is purged by PCM
control when the engine coolant temperature is over 60
C
(140
F), the IAT reading is over 10
C (50
F), and the
engine has been running. Air is drawn into the canister
through the air inlet grid. The air mixes with the vapor and
the mixture is drawn into the intake manifold.
EVAP Emission Control System Operation
The EVAP canister purge is controlled by a solenoid valve
that allows the manifold vacuum to purge the canister.
The powertrain control module (PCM) supplies a ground
to energize the solenoid valve (purge on). The EVAP
purge solenoid control is pulse-width modulated (PWM)
(turned on and off several times a second). The duty
cycle (pulse width) is determined by engine operating
conditions including load, throttle positron, coolant
temperature and ambient temperature. The duty cycle is
calculated by the PCM. The output is commanded when
the appropriate conditions have been met. These
conditions are:

The engine is fully warmed up.

The engine has been running for a specified time.

The IAT reading is above 10
C (50
F).

6E±587
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
055RW004
Non-Electrical Components

Purge/Vacuum Hoses. Made of rubber compounds,
these hoses route the gasoline fumes from their
sources to the canister and from the canister to the
intake air flow.

EVAP Canister. Mounted on a bracket ahead of the
fuel tank, the canister stores fuel vapors until the PCM
determines that engine conditions are right for them
to be removed and burned.

Fuel Tank. The tank has a built-in air space designed
for the collection of gasoline fumes.
060R200081

Vacuum Source. The vacuum source is split between
two ports, one on either side of the throttle body.

Fuel Cap. The fuel cap is designed to be an integral
part of the EVAP system.System Fault Detection
The EVAP leak detection strategy is based on applying
vacuum to the EVAP system and monitoring vacuum
decay. The PCM monitors vacuum level via the fuel tank
pressure sensor. At an appropriate time, the EVAP purge
solenoid and the EVAP vent solenoid are turned ªON,º
allowing the engine vacuum to draw a small vacuum on
the entire evaporative emission system.
After the desired vacuum level has been achieved, the
EVAP purge solenoid is turned ªOFF,º sealing the system.
A leak is detected by monitoring for a decrease in vacuum
level over a given time period, all other variables
remaining constant. A small leak in the system will cause
DTC P0442 to be set.
If the desired vacuum level cannot be achieved in the test
described above, a large leak or a faulty EVAP purge
solenoid is indicated.
Leaks can be caused by the following conditions:

Disconnected or faulty fuel tank pressure sensor

Missing or faulty fuel cap

Disconnected, damaged, pinched, or blocked EVAP
purge line

Disconnected or damaged EVAP vent hose

Disconnected, damaged, pinched, or blocked fuel
tank vapor line

Disconnected or faulty EVAP purge solenoid

Disconnected or faulty EVAP vent solenoid

Open ignition feed circuit to the EVAP vent or purge
solenoid

Damaged EVAP canister

Leaking fuel sender assembly O-ring

Leaking fuel tank or fuel filler neck
A restricted or blocked EVAP vent path is detected by
drawing vacuum into the EVAP system, turning ªOFFº the
EVAP vent solenoid and the EVAP purge solenoid (EVAP
vent solenoid ªOPEN,º EVAP purge Pulse Width
Modulate (PWM) ª0%º) and monitoring the fuel tank
vacuum sensor input. With the EVAP vent solenoid open,
any vacuum in the system should decrease quickly
unless the vent path is blocked. A blockage like this will
set DTC P0446 and can be caused by the following
conditions:

Faulty EVAP vent solenoid (stuck closed)

Plugged, kinked or pinched vent hose

Shorted EVAP vent solenoid driver circuit

Plugged EVAP canister
The PCM supplies a ground to energize the purge
solenoid (purge ªONº). The EVAP purge control is PWM,
or turned ªONº and ªOFF,º several times a second. The
duty cycle (pulse width) is determined by engine
operating conditions including load, throttle position,
coolant temperature and ambient temperature. The duty
cycle is calculated by the PCM and the output is
commanded when the appropriate conditions have been
met.

6E±588
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
The system checks for conditions that cause the EVAP
system to purge continuously by commanding the EVAP
vent solenoid ªONº and the EVAP purge solenoid ªOFFº
(EVAP vent solenoid ªCLOSED,º EVAP purge PWM
ª0%º). If fuel tank vacuum level increases during the test,
a continuous purge flow condition is indicated, which will
set a DTC P1441. This can be cause by the following
conditions:

EVAP purge solenoid leaking

EVAP purge and engine vacuum lines switched at the
EVAP purge solenoid

EVAP purge solenoid driver circuit grounded
Fuel vapor recovery system
060R100095Separator attaches after hose evaporative fuel. It
protects EVAP Canister from liquid fuel. It guarantees
EVAP Canister performance. When vibration bounces
fuel level, liquid fuel will accrete to EVAP Canister. It
separates liquid fuel.
General Description (Exhaust Gas
Recirculation (EGR) System)
EGR Purpose
The exhaust gas recirculation (EGR) system is use to
reduce emission levels of oxides of nitrogen (NOx). NOx
emission levels are caused by a high combustion
temperature. The EGR system lowers the NOx emission
levels by decreasing the combustion temperature.
057RW002
Linear EGR Valve
The main element of the system is the linear EGR valve.
The EGR valve feeds small amounts of exhaust gas back
into the combustion chamber. The fuel/air mixture will be
diluted and combustion temperatures reduced.
Linear EGR Control
The PCM monitors the EGR actual positron and adjusts
the pintle position accordingly. The uses information from
the following sensors to control the pintle position:

Engine coolant temperature (ECT) sensor.

Throttle position (TP) sensor.

Mass air flow (MAF) sensor.
Linear EGR Valve Operation and Results
of Incorrect Operation
The linear EGR valve is designed to accurately supply
EGR to the engine independent of intake manifold
vacuum. The valve controls EGR flow from the exhaust
to the intake manifold through an orifice with a PCM
controlled pintle. During operation, the PCM controls
pintle position by monitoring the pintle position feedback
signal. The feedback signal can be monitored with a Tech
2 as ªActual EGR Pos.º ªActual EGR Pos.º should always
be near the commanded EGR position (ºDesired EGR
Pos.º). If a problem with the EGR system will not allow the
PCM to control the pintle position properly, DTC P1406
will set. The PCM also tests for EGR flow. If incorrect flow
is detected, DTC P0401 will set. If DTCs P0401 and/or
P1406 are set, refer to the DTC charts.
The linear EGR valve is usually activated under the
following conditions:

Warm engine operation.

Above-idle speed.
Too much EGR flow at idle, cruise or cold operation may
cause any of the following conditions to occur:

Engine stalls after a cold start.

Engine stalls at idle after deceleration.

7A±5 AUTOMATIC TRANSMISSION (4L30±E)
Normal Operation Of 2002 4L30±E
Transmission
Torque Converter Clutch (Electronically
Controlled Capacity Clutch : ECCC)
Application Conditions:
The clutch apply is controlled by moving the converter
clutch control valve by commanding Torque Converter
Clutch (TCC) solenoid using the PWM signal.
The TCC is normally applied in 2nd, 3rd and 4th gears
only when all of the following conditions exist:
Ð The engine coolant temperature is above 70
C
(158
F) and ATF temperature is above 18
C
(64.5
F).
Ð The shift pattern requests TCC apply.
Moreover, TCC is always applied in 2nd, 3rd and 4th
gears when the transmission oil temperature is above
135
C (275
F).
This mode should be canceled at 125
C (257
F).
ATF Warning Lamp
The ATF warning lamp will be constantly on (not flashing)
if the transmission oil temperature is above 145
C
(293
F).
The ATF warning lamp goes off again when the
transmission oil temperature is below 125
C (257
F).
Reverse Lock Out
With the selector lever in reverse position, the PCM will
not close the PWM solenoid until the vehicle is below 11
km/h (6.8 mph), thus preventing reverse engagement
above this speed.
Diagnosis
Introduction
The systematic troubleshooting information covered by
this Section offers a practical and systematic approach to
diagnosing 4L30±E transmission, using information that
can be obtained from road tests, electrical diagnosis, oil
pressure checks or noise evaluation.
The key to correcting a complaint is to make use of all of
the available symptoms and logically letting them direct
you to the cause.
When dealing with automatic transmission complaints, it
is best to gather as many symptoms as possible before
making the decision to remove the transmission from the
vehicle.
Frequently, the correction of the complaint does not
require removal of the transmission from the vehicle.
Driver Information
To analyze the problem fill out a complete description of
the owner's complaint.
Please draw a circle around the right information and
complete the following form. (The next page is an
example of a completed form). You can draw a circle
around many numbers if you are not sure.