ISUZU AXIOM 2002 Service Repair Manual

6E±584
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A continuous purge condition with no purge commanded
by the PCM will set a DTC P1441.
Poor idle, stalling and poor driveability can be caused by:

A malfunctioning purge solenoid.

A damaged canister.

Hoses that are split, cracked, or not connected
properly.
Enhanced Evaporative Emission Control
System
The basic purpose of the Enhanced Evaporative
Emissions control system is the same as other EVAP
systems. A charcoal-filled canister captures and stores
gasoline fumes. When the PCM determines that the time
is right, it opens a purge valve which allows engine
vacuum to draw the fumes into the intake manifold.
The difference between this and other systems is that the
PCM monitors the vacuum and/or pressure in the system
to determine if there is any leakage. If the PCM
determines that the EVAP system is leaking or not
functioning properly, it sets a Diagnostic Trouble Code
(DTC) in the PCM memory.
The enhanced EVAP system is required to detect
evaporative fuel system leaks as small as 0.020 in. (1.0
mm) between the fuel filler cap and purge solenoid. The
system can test the evaporative system integrity by
applying a vacuum signal (ported or manifold) to the fuel
tank to create a small vacuum. The PCM then monitors
the ability of the system to maintain the vacuum. If the
vacuum remains for a specified period of time, there are
no evaporative leaks and a PASS report is sent to the
diagnostic executive. If there is a leak, the system either
will not achieve a vacuum, or a vacuum cannot be
maintained. Usually, a failure can only be detected after a
cold start with a trip of sufficient length and driving
conditions to run the needed tests. The enhanced EVAP
system diagnostic will conduct up to eight specific
sub-tests to detect fault conditions. If the diagnostic fails
a sub-test, the PCM will store a Diagnostic Trouble Code
(DTC) to indicate the type of detected.

6E±585
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
140R200004
Legend
(1) Fuel Filler Cap
(2) Fuel Tank
(3) Rollover Valve
(4) Fuel Pump and Sender Assembly
(5) Fuel Filter
(6) Fuel Rail Right
(7) Right Bank
(8) Fuel Rail Left
(9) Left Bank(10) Fuel Pressure Control Valve
(11) Common Chamber
(12) Duty Solenoid Valve (EVAP Purge Solenoid)
(13) Throttle Valve
(14) Canister (EVAP Canister)
(15) Vent Hose
(16) Vent Solenoid Valve
(17) Separator
(18) Shut off Valve (With Over Pressure Relief
Valve) and Vapor Pressure Sensor

6E±586
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Electrical Components
The electrical components that make up the enhanced
EVAP system are:

Fuel Tank (Vapor) Pressure Sensor. The fuel tank
pressure sensor is a three-wire strain gauge sensor
similar to a common MAP sensor. However, the fuel
tank pressure sensor has very different electrical
characteristics due to its pressure differential design.
The sensor measures the difference between the air
pressure (or vacuum) in the fuel tank and the outside
air pressure.
The sensor mounts at the top of the fuel pump
assembly. A three-wire electrical harness connects it to
the PCM. The PCM supplies a five-volt reference
voltage and a ground to the sensor. The sensor will
return a voltage between 0.1 and 4.9 volts. When the
air pressure in the fuel tank is equal to the outside air
pressure, such as when the fuel cap is removed, the
output voltage of the sensor will be 1.3 to 1.7 volts.
When the air pressure in the fuel tank is 4.5 in. H2O
(1.25 kPa), the sensor output voltage will be 0.5 + 0.2 V.
When there is neither vacuum nor pressure in the fuel
tank, the sensor voltage will be 1.5 V. At ±14 in. H2O
(±3.75 kPa), the sensor voltage will be 4.5 + 0.2 V.

EVAP Canister Purge Solenoid. Normally closed, the
purge solenoid opens upon the PCM's signal to allow
engine vacuum to purge gasoline fumes from the
canister. Mounted on the water pipe to front of the
engine assembly.
060R200080

EVAP Canister Vent Solenoid. Located next to the
canister, the vent solenoid opens to allow air into the
EVAP system. Fresh air is necessary to completely
remove gasoline fumes from the canister during
purge. The EVAP vent solenoid closes to seal off the
evaporative emissions system for leak testing.
060R200081

Fuel Level Sensor. The fuel level sensor is an
important input to the PCM for the enhanced EVAP
system diagnostic. The PCM needs fuel level
information to know the volume of fuel in the tank.
The fuel level affects the rate of change of air
pressure in the EVAP system. Several of the
enhanced EVAP system diagnostic sub-tests are
dependent upon correct fuel level information. The
diagnostic will not run when the tank is less than 15%
or more than 85% full. Be sure to diagnose any Fuel
Level Sensor DTCs first, as they can cause other
DTCs to set.
014RW114

Manifold Absolute Pressure (MAP) Sensor. The
PCM compares the signals from the fuel tank
pressure sensor and the MAP sensor to ensure that a
relative vacuum is maintained the EVAP system.

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.

6E±589
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Vehicle surges during cruise.

Rough idle.

DTC P0300 (misfire detected).
Too little or no EGR flow may allow combustion
temperatures to get too high. This could cause:

Spark knock (detonation).

Engine overheating.

Emission test failure.

DTC P0401 (EGR flow test).

Poor fuel economy.
0017
EGR Pintle Position Sensor
The PCM monitors the EGR valve pintle position input to
endure that the valve responds properly to commands
from the PCM and to detect a fault if the pintle position
sensor and control circuits are open or shorted. If the
PCM detects a pintle position signal voltage outside the
normal range of the pintle position sensor, or a signal
voltage that is not within a tolerance considered
acceptable for proper EGR system operation, the PCM
will set DTC P1406.
General Description (Positive
Crankcase Ventilation (PCV) System)
Crankcase Ventilation System Purpose
The crankcase ventilation system is use to consume
crankcase vapors in the combustion process instead of
venting them to the atmosphere. Fresh air from the
throttle body is supplied to the crankcase and mixed with
blow-by gases. This mixture is then passed through the
positive crankcase ventilation (PCV) valve into the
common chamber.
Crankcase Ventilation System Operation
The primary control is through the positive crankcase
ventilation (PCV) valve. The PCV valve meters the flow at
a rate that depends on the intake vacuum. The PCV valve
restricts the flow when the inlet vacuum is highest. Inaddition, the PCV valve can seal the common chamber
off in case of sudden high pressure in the crankcase.
028RV002While the engine is running, exhaust fuses and small
amounts of the fuel/air mixture escape past the piston
rings and enter the crankcase. These gases are mixed
with clean air entering through a tube from the air intake
duct.
060R200063During normal, part-throttle operation, the system is
designed to allow crankcase gases to flow through the
PCV valve into the throttle body to be consumed by
normal combustion.

6E±590
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A plugged valve or PCV hose may cause the following
conditions:

Rough idle.

Stalling of slow idle speed.

Oil leaks.

Sludge in the engine.
A leaking PCV hose would cause:

Rough idle.

Stalling.

High idle speed.

6E±591
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Special Tools
ILLUSTRATIONTOOL NO.
TOOL NAME
J 39200
High Impedance
Multimeter (Digital
Voltmeter ± DVM)
(1) PCMCIA Card
(2) RS232 Loop Back
Connector
(3) SAE 16/19 Adapter
(4) DLC Cable
(5) TECH±2
J 34142-B
Unpowered Test Light
Connector Test Adapter
Kit J 35616-A/BT-8637
J 26792/BT-7220-1
Spark Tester
J 34730-E
Port Fuel Injection
Diagnostic Kit
ILLUSTRATIONTOOL NO.
TOOL NAME
J 37027-A
IAC Motor Analyzer
J 23738-A
Vacuum Pump with
Gauge
BT-8515/8515V
Exhaust Back Pressure
Tester
J 39194-B
Heated Oxygen Sensor
Wrench
J 35689-A
Terminal Remover
J 28742-A
Weather Pack II
Terminal Remover

6E±592
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
ILLUSTRATIONTOOL NO.
TOOL NAME
J 39021-90
Injector Switch Box
J 39021-65
Injector Test Light
J 41413

EVAP Pressure/Purge
Diagnostic Station
J 41416
Ultrasonic Leak Detector
1. J 41413 EVAP Pressure/Purge Diagnostic Station is
a multipurpose tool which is used to perform several
diagnostic procedures for enhanced emission
testing. The station will accommodate a nitrogen gas
filled cylinder which is used to pressurize the vehicle
EVAP system for a leakdown test and leak location
test when a vehicle is repaired for leakage in the
enhanced evaporative emission control system. It
also has two additional gauges (inches of mercury
and inches of water) which are used to measure both
source vacuum and EVAP canister purge vacuum to
verify correct operation and vapor flow within the
canister purge circuit.
2. J 41416 Ultrasonic Leak Detector is a
microprocessor-based device used to detect leaks in
the enhanced evaporative emission control system.
The evaporative system is pressurized to 30 inches of
water using the J 41413 EVAP Pressure/Purge
Diagnostic System. Small leaks in the EVAP system
will emit sound at a high frequency undetectable by a
human ear but detectable with the J 41416. The
technician traces along the evaporative system and
can pinpoint leaks due to corroded lines, cracked
hoses, or a damaged EVAP component. The
detector includes a high quality set of headphones to
block out surrounding shop noise and the LED
sensitivity meter allows a visual reference for locating
leaks in conjunction with the audio output heard
through the headphones. Powered by (1) nine volt
battery.

6F±1
ENGINE EXHAUST (6VE1 3.5L)
AXIOM
ENGINE
ENGINE EXHAUST (6VE1 3.5L)
CONTENTS
Service Precaution 6F±1. . . . . . . . . . . . . . . . . . . . . .
General Description 6F±2. . . . . . . . . . . . . . . . . . . . .
Three Way Catalytic Converter RH and
Forked Exhaust Pipe 6F±3. . . . . . . . . . . . . . . . . . . .
Three Way Catalytic Converter RH and
Forked Exhaust Pipe and Associated Parts 6F±3
Removal 6F±3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F±3. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Three Way Catalytic Converter LH and
Forked Exhaust Pipe 6F±4. . . . . . . . . . . . . . . . . . . .
Three Way Catalytic Converter LH and
Forked Exhaust Pipe and Associated Parts 6F±4
Removal 6F±4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F±4. . . . . . . . . . . . . . . . . . . . . . . . . . . . Forked Exhaust Pipe 6F±5. . . . . . . . . . . . . . . . . . . .
Forked Exhaust Pipe and Associated
Parts 6F±5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6F±5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F±5. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Silencer 6F±6. . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Silencer and Associated Parts 6F±6. . .
Removal 6F±6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F±6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Exhaust pipe 6F±7. . . . . . . . . . . . . . . . . . . . . . .
Rear Exhaust pipe and Associated Parts 6F±7.
Removal 6F±7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F±7. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 6F±8. . . . . . . . . . . . .
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING, REFER TO
THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.