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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 322

6E–318

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0440 EVAP System

060RY00398

Circuit Description

The evaporative system includes the following
components:

Fuel tank

EVAP canister purge duty solenoid valve

Fuel tank (vapor) pressure sensor

Fuel pipes and hoses

Vapor lines

Fuel cap

Evaporative emissions canister

Purge lines

EVAP canister vent valve (purge solenoid)

The evaporative leak detection diagnostic strategy is
based on applying vacuum to the EVAP system and
monitoring vacuum decay. The powertrain control
module (PCM) monitors vacuum level via the fuel tank
pressure sensor input. At an appropriate time, the EVAP
canister purge solenoid and the EVAP canister vent
solenoid are turned “ON”, allowing engine vacuum to
draw a small vacuum on the entire evaporative emissions
system. If a sufficient vacuum level cannot be achieved, a
large leak or a faulty EVAP canister purge solenoid is
indicated. This 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 canister duty solenoid

Open ignition feed circuit to the EVAP canister vent
solenoid

Damaged EVAP canister

Leaking fuel sender assembly O-ring

Leaking fuel tank or fuel filler neck

Any of the above conditions can set DTC P0440.

Conditions for Setting the DTC

No TP sensor, IAT sensor, ECT sensor, or MAP sensor
DTCs set.

Start-up engine coolant temperature is less than 32

(90

F).

Start-up engine coolant temperature is not more than
7

C (13

F) greater than start-up intake air

temperature.

Start-up intake air temperature is greater than 4

(39

F) .

Start-up intake air temperature is not more than 2

F) greater than start-up engine coolant

temperature.

Vehicle speed is less than 5 mph (8 km/h).

Throttle position is greater than 3%.

Minimal fuel slosh.

BARO is greater than 70 kPa.

The EVAP system is unable to achieve or maintain
vacuum during the diagnostic test.

6E–319

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Engine speed is less than 1200 RPM.

Above conditions are present for 60 to 180 seconds.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

The PCM will store conditions which were present
when the DTC set as Freeze Frame and in the Failure
Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” when the diagnostic
has been run and the fault condition is no longer
present.

A history DTC P0440 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0440 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

Cracked or punctured EVAP canister.

Damaged or disconnected source vacuum line, EVAP
purge line, 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.

Kinked, pinched, or plugged vacuum source, EVAP
purge, or fuel tank vapor line–Verify that the lines are
not restricted.

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 P0440.

3. Checks the fuel tank pressure sensor at ambient

pressure.

4. Determines whether or not the EVAP system can be

sealed sufficiently to be pressurized. If not, the
large leak must be located and corrected before
continuing with diagnosis.

5. Verifies that the fuel tank pressure sensor accurately

reacts to EVAP system pressure changes.

8. Checks for a blocked EVAP canister purge solenoid.

The PCM commands the EVAP canister purge
solenoid “OFF” (open) and the vent solenoid “ON”
(closed) with the Tech 2 “System Perf”, EVAP
output control function activated. Any pressure in
the system should be released through the EVAP
canister purge solenoid within a few seconds when
“System Perf”, is activated.

9. Ensures that sufficient source vacuum is present at

the EVAP canister purge solenoid.

DTC P0440 – EVAP System

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Is DTC P0452 or P0453 also set?

—

Go to

other

DTC first

Go to

Step 3

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?

1.51 V

Go to

Step 4

Go to

DTC

P0452 or

DTC P0453

1. Replace the fuel cap.
2. Engine is running.
3. Observe “Fuel Tank Vacuum” on the Tech 2.

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

1.47–1.51 V

Go to

Step 7

Go to

Step 6

6E–320

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0440 – EVAP System

(Cont'd)

Step

Yes

Value(s)

Action

Ignition “OFF”.

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.
Observe “Fuel tank pressure” on the Tech 2.

Does the Tech 2 indicate “Fuel tank pressure” at the
specified value?

1.47–1.51 V

Go to

Step 8

Go to

Step 7

1. Visually/physically check for the following

conditions:

Restricted fuel tank vapor line.

Restricted EVAP purge line.

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

Was a problem found?

—

Verify repair

Go to

DTC

P0452 or

DTC P0453

1. Visually/physically check for the following

conditions:

Vent hose disconnected or the damaged.

EVAP canister damaged.

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

Was a problem found?

—

Verify repair

Go to

Step 11

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?

—

Verify repair

Go to

Step 9

Replace the EVAP canister purge solenoid.

Is the action complete?

—

Verify repair

—

Locate and repair cause of no source vacuum to the
EVAP canister purge solenoid.

Is the action complete?

—

Verify repair

—

Replace the EVAP canister vent solenoid.

Is the action complete?

—

Verify repair

—

6E–321

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0442 EVAP System Small Leak Detected

060RY00398

Circuit Description

The evaporative system includes the following
components:

Fuel tank

EVAP canister vent solenoid

Fuel tank (vapor) pressure sensor

Fuel pipes and hoses

Vapor lines

Fuel cap

Evaporative emissions canister

Purge lines

EVAP canister purge solenoid

The evaporative leak detection diagnostic strategy is
based on applying vacuum to the EVAP system and
monitoring vacuum decay. The powertrain control
module (PCM) monitors vacuum level via the fuel tank
pressure sensor input. At an appropriate time, the EVAP
canister purge solenoid and the EVAP canister vent
solenoid are turned “ON”, allowing engine vacuum to
draw a small vacuum on the entire evaporative emissions
system. After the desired vacuum level has been
achieved, the EVAP canister purge solenoid is turned
“OFF”, 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.

Conditions for Setting the DTC

No TP sensor, ECT sensor, Tank pressure sensor, IAT
sensor, or MAP sensor DTCs set.

BARO is more than 70 kPa.

Engine speed is less than 1200 RPM.

Fuel level is between 15% and 85%.

Vehicle speed is less than 5 mph (8 km/h).

The DTC P0440 diagnostic test has passed.

A vacuum decay condition, indicating a small leak, is
detected during the diagnostic test.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected fault.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

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 P0442 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0442 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

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