Isuzu 2000 Trooper Workshop Manual page 1214

Diagnostic Aids
Check for the following conditions:
D Cracked or punctured EVAP canister.
D Damaged source vacuum line, EVAP purge line, EVAP
vent hose or fuel tank vapor line. to wire connection.
D 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.
Diagnostic Trouble Code(DTC)P0456 EVAP Very Small Leak
Step
1 Was the "On-Board(OBD)System Check"performed?
2 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?
3 1. Visually/physically
conditions:
D
Vent hose disconnected or darmaged.
D
EVAP canister damaged.
D
Fuel cap damaged
2. If a problem is found,repair as necessary.
Was a problem found?
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?
5 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?
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?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Action
check for the following
D 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.
Value(s)
— Go to Step 2
1.51V Go to Step 3
— Verify repair
Go to Step 5
—
Diagnostic
1.02–1.86 V
— Verify repair
6E–345
Yes No
Go to OBD
System
Check
Go to Fuel
Tank
Pressure
System
Go to Step 4
Refer to
Diagnostic
Aids
Refer to
Aids Go to Step 6
Go to Step 7