Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 323

6E–322

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Aids

Check for the following conditions:

Cracked or punctured EVAP canister.

Damaged source vacuum line, EVAP purge line, EVAP
vent hose or fuel tank vapor line.

Poor connection at PCM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness–Inspect the wiring harness to the
EVAP canister vent solenoid, EVAP canister purge
solenoid and the fuel tank pressure sensor for an
intermittent open or short circuit.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often

the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If an EVAP canister vent solenoid or an EVAP

canister purge solenoid electrical fault is present,
the purge system will not operate correctly.
Repairing the electrical fault will very likely correct
the condition that set DTC P0442.

3. Checks the fuel tank pressure sensor at ambient

pressure.

4. Verifies that the fuel tank pressure sensor accurately

reacts to EVAP system pressure changes.

DTC P0442 – EVAP System Leak Detected

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Ignition “OFF”.
2. Remove the fuel cap.
3. Ignition “ON”.
4. Observe “Fuel Tank Pressure” on the Tech 2.

Does the Tech 2 indicate “Fuel Tank Pressure” at the
specified value?

1.51V

Go to

Step 3

Go to

Fuel

Tank

Pressure

System

IMPORTANT: Before continuing with diagnosis, zero
the EVAP pressure and vacuum gauges on EVAP
pressure/purge cart J 41413 (refer to tool operating
instructions).

1. Replace the fuel cap.
2. Capture Failure Records data for DTC P0442 and

clear DTCs.

3. Connect the EVAP pressure/purge cart J 41413 to

the EVAP service port.

4. Using the Tech 2, command the EVAP canister vent

solenoid “ON” (closed).

5. Using the EVAP pressure/purge cart J 41413,

pressurize the EVAP system to the specified value.

6. Observe “Fuel Tank Pressure” on the Tech 2.

Does the Tech 2 indicate “Fuel Tank Pressure” at the
specified value?

1.47V

Go to

Step 4

Go to

Fuel

Tank

Pressure

System

1. Ignition “ON”, engine idling.
2. Using the Tech 2, command the EVAP canister vent

solenoid “ON” (closed).

3. Using the EVAP pressure/purge cart J 41413,

pressurize the EVAP system to 15 in. H

4. Switch the rotary switch on the cart to “HOLD” and

observe the EVAP pressure gauge.

Does the pressure decrease to less than the specified
value within 2 minutes?

1.47 – 1.51V

Go to

Step 5

Refer to

Diagnostic

Aids

6E–323

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0442 – EVAP System Leak Detected

(Cont'd)

Step

Yes

Value(s)

Action

1. Disconnect the fuel tank vapor line and the EVAP

purge line from the EVAP canister.

2. Block the canister fitting for the fuel tank vapor line.
3. Connect a hand vacuum pump to the canister fitting

for the EVAP purge line.

4. Ensure that the EVAP canister vent solenoid is still

commanded “ON” (closed).

5. Attempt to apply vacuum to the EVAP canister.

Can the vacuum be maintained at the specific value?

1.46V

Go to

Step 8

Go to

Step 6

1. Visually/physically check for the following

conditions:

Vent hose disconnected or damaged.

EVAP canister damaged.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Go to

Step 10

Go to

Step 7

Replace the EVAP canister vent solenoid.

Is the action complete?

—

Go to

Step 10

—

1. Visually/physically check for the following

conditions:

Missing or faulty fuel cap.

Disconnected or leaking fuel tank vapor line.

Disconnected or damaged EVAP purge line.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Go to

Step 10

Go to

Step 9

1. Using Tech 2, command the EVAP canister vent

solenoid “ON” (closed).

2. With the cart connected to the EVAP service port,

continuously attempt to pressurize the EVAP
system by leaving the cart control knob in the
pressurize position.

3. Using ultrasonic leak detector J 41416, locate and

repair leak in EVAP system. (It may be necessary to
partially lower the fuel tank to examine the
connections on top of the tank.)

Is the action complete?

—

Go to

Step 10

—

1. Ignition “ON”, engine not running.
2. Using the Tech 2, command the EVAP canister vent

solenoid “ON” (closed).

3. Using the EVAP pressure/purge cart J 41413,

pressurize and monitor the EVAP system to 15 in.
H

4. Switch the rotary switch on the cart to “HOLD” and

observe the EVAP pressure gauge.

Does the pressure decrease to less than the specified
value within 2 minutes?

2.14V

Go to

Step 2

Verify repair

6E–324

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0444 EVAP Purge Control Circuit Open

060RY00398

Circuit Description

The canister purge solenoid valve is controlled by the
Power Train Control Module (PCM).The PCM monitors
vacuum level via the fuel tank pressure sensor input.
At an appropriate time, the EVAP canister purge solenoid
is “ON,” allowing engine vacuum to draw a small vacuum
on the entire evaporative emissions system.

Conditions for setting the DTC

The Ignition is “ON”.

Engine is running.

System voltage is between 11.5 volts and 16 volts.

Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the DTC was set in the Failure Records data only.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0444 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.

DTC P0444 can be cleared using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

An intermittent may be caused by the following:

Poor connections.

Mis routed harness.

Rubbed through wire insulation.

Broken wire inside the insulation.

Check for the following conditions:

Poor connection at PCM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to the
sensor.
A change in the display will indicate the location of
the fault. If DTC P0444 cannot be duplicated, the
information included in the Failure Records data can
be useful in determined vehicle mileage since the
DTC was last set.

If it is determined that the DTC occurs intermittently,
performing the DTC P0444 Diagnostic Chart may
isolate the cause of the fault.

6E–325

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0444 EVAP Purge Control Circuit Open

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Install the Tech 2.
2. Ignition is “ON”,
3. Engine is “ON” and operate the accelerator pedal

for 3 or 4 times.

4. Observe the EVAP purge solenoid reading on the

Tech 2.

Is the EVAP purge solenoid reading near the specified
value?

More than 1%

Refer to

Diagnostic

Aids

Go to

Step 3

Check the power supply circuit.

1. Ignition is “OFF”.
2. Disconnect the canister purge solenoid valve.
3. Ignition is “ON”.
4. Using a DVM, measure at the EVAP purge solenoid

connector between ground and voltage supply.

Was the measurement near the specified value?

Battery

voltage

Go to

Step 4

Go to

Step 5

Check the signal circuit for the EVAP purge solenoid.

1. Ignition is “OFF”.
2. Disconnect the canister purge solenoid valve.
3. Disconnect the PCM.
4. Check the circuit between EVAP purge solenoid

connector and PCM connector.

Is the problem found?

—

Go to

Step 5

Go to

Step 6

Repair the circuit as necessary.

Is the action complete?

—

Verify repair

—

Check the canister purge solenoid valve. Using a DVM,
measure resistance for purge solenoid valve connector
terminal.

Is the purge solenoid valve resistance within the
specified values?

25–30

(at

F{20

C})

Go to

Step 8

Go to

Step 7

Replace the canister purge solenoid valve.

Is the action complete?

—

Verify repair

—

Replace the

IMPORTANT: The replacement PCM must be
programmed.

Refer to

ON-Vehicle Service in Power Control Module

and Sensors for procedures.

And also refer to latest Service Bulletin. Check to see
if the latest software is released or not.

And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

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