Isuzu Trooper (2000 year). Manual - part 304

6E–345

TROOPER 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. to wire connection.

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 hanrness-Inspect the wiring harness to the
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.

Diagnostic Trouble Code(DTC)P0456 EVAP Very Small Leak

Step

Action

Value(s)

Yes

Was the “On-Board(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

1. Visually/physically check for the following

conditions:

Vent hose disconnected or darmaged.

EVAP canister damaged.

Fuel cap damaged

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

Was a problem found?

—

Verify repair

Go to

Step 4

1. Ignition “ON”, engine “OFF”.
2. Install the fuel cap.
3. Review and record Tech 2 Failure Records data.
4. Operate the vehicle within Failure Records

conditions as noted.

5. Using theTech 2,monitor the “DTC” info for DTC

P0456.

Does the Tech 2 indicate DTC P0456?

—

Go to

Step 5

Refer to

Diagnostic

Aids

1. Ignition “ON”, engine idling.
2. Observe “Fuel Tank Pressure” on the Tech 2.

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

1.02–1.86 V

Refer to

Diagnostic

Aids

Go to

Step 6

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

solenoid “ON” (closed)

3. Observe “EVAP canister vent solenoid operation”.

second value?

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

Was a problem found?

—

Verify repair

Go to

Step 7

6E–346

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code(DTC)P0456 EVAP Very Small Leak

(Cont'd)

Step

Yes

Value(s)

Action

1. Visually/physically check for the following

conditions:

Disconnected or leaking fuel tank vapor line.

Disconnected or damage EVAP purge line.

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

Was a problem found?

—

Verify repair

Refer to

Diagnostic

Aids

6E–347

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0462 Fuel Level Sensor Circuit–Low Voltage

060RY00163

Circuit Description

The fuel level sensor is an important input to powertrain
control module (PCM) for the enhanced evaporative
system diagnostic. Fuel level information is needed for
the PCM to know the volume of fuel in the tank. The fuel
level affects the rate of change in air pressure in the
evaporative system. Several of the enhanced
evaporative system diagnostic sub-tests are dependent
upon correct fuel level information. The diagnostic will not
run when the tank is greater than 85%, or less than 15%
full. Fuel level DTCs should be diagnosed before other
evaporative system DTCs because they can cause other
DTCs to be set.
The sending unit is a float in the fuel tank which moves a
wiper arm across a variable resistor. Low fuel level
causes high resistance in the sending unit, and this is
recognized by the PCM because the circuit operates at a
corresponding low voltage. When the circuit is
continuously open or has a high resistance connection,
DTC P0462 is set.

Conditions for Setting the DTC

Fuel tank level “slosh test” is completed.

Fuel tank level “main test” is completed.

Fuel tank level data is valid.

Fuel tank level signal is less than a specified value.

There are 100 test failures within a 200-test sample.

Action Taken When the DTC Sets

The PCM will not turn the malfunction indicator lamp
(MIL) “ON.”

The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.

Conditions for Clearing the DTC

The PCM will turn the MIL “OFF” after three
consecutive trips without a fault condition present. A
history DTC will be cleared if no fault conditions have
been detected for 40 warm-up cycles (engine coolant
temperature has risen 4

C (40

F) from the start-up

ECT, and ECT exceeds 71

C (160

F) during that

same ignition cycle).

DTC P0462 can be cleared by using the scan tool
“Clear Info” function or by disconnecting the PCM
battery feed.

Diagnostic Aids

Damaged harness–Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
fuel level display on the scan tool while moving
connectors and wiring harnesses related to the sensor.
A change in the display will indicate the location of the
fault.

6E–348

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
8. The following chart can be used to check the

sending unit:

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