Dtc P0446- Evap Canister Vent Blocked . 6E-348 - Isuzu Trooper 1999 Workshop Manual

6E–348
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Ignition "ON."
2. Capture Failure Records data for DTC P0446 and
clear DTCs.
3. Ignition "OFF."
4. Remove the fuel cap.
5. Ignition "ON."
6. Observe "Fuel Tank Pressure" on the Tech 2.
Does Tech 2 indicate "Fuel Tank Pressure" at the
specified value?
3 IMPORTANT: Before continuing with diagnosis, zero
the EVAP pressure and vacuum gauges on the EVAP
pressure/purge cart J 41413 (refer to tool operating
instructions).
1. Replace the fuel cap.
2. Using the Tech 2, command the EVAP vent solenoid
"ON" (closed).
3. Connect the EVAP pressure/purge cart J 41413 to
the EVAP service port.
4. Using the EVAP pressure/purge cart J 41413,
pressurize the EVAP system to the specified value.
5. Observe "Fuel Tank Pressure" on the Tech 2.
Does Tech 2 indicate "Fuel Tank Pressure" at the
specified value?
4 1. Maintain the EVAP pressure at 5 in. at H2O.
2. Using Tech 2, command the EVAP vent solenoid
"OFF" (open) while observing the EVAP pressure
gauge on the cart J 41413.
Does the EVAP pressure return to the specified value
within 5 seconds?
5 1. Disconnect the large vent hose (marked "AIR") from
the EVAP canister.
2. Switch the rotary switch on the cart J 41413 to
"PURGE."
3. Ignition "ON," engine idling at normal operating
temperature.
4. Observe vacuum gauge for 5 seconds while holding
the engine speed at 2500 RPM.
Does the vacuum remain less than the specified value?
6 1. Inspect the vent hose between the EVAP canister
and the EVAP canister vent solenoid for kinks,
pinched areas, or any other form of blockage.
2. If a problem is found, repair as necessary.
Was a problem found?
7 Replace the EVAP canister vent solenoid.
Is the action complete?
DTC P0446– EVAP Canister Vent Blocked
Action Value(s) Yes
— Go to Step 2
Go to Step 3
1.51V
1.52 – 1.69V Go to Step 4
Refer to
Diagnostic
0 in. H2O Aids
30 in. H2O Go to Step 6
— Go to Step 9
— Go to Step 9
No
Go to OBD
System
Check
Go to Fuel
Tank
Pressure
System
Go to Fuel
Tank
Pressure
System
Go to Step 5
Go to Step 8
Go to Step 7
—