Isuzu 1999 RODEO Workshop Manual page 891

6E1–264 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
f Fuel Tank vacuum is greater than 39 cm (15.35 inches)
of water.
Action Taken When the DTC Sets
f The Malfunction Indicator Lamp (MIL) will illuminate.
f The PCM will records operating conditions at the time
the diagnostic fails. The Freeze Frame and Failure
Records buffers will store this information.
f A history Diagnostic Trouble Code is stored.
Conditions for Clearing the MIL/DTC
f The MIL will turn off after 3 consecutive ignition cycles
in which the diagnostic runs without a fault.
f A history DTC will clear after 40 consecutive warm up
cycles without a fault.
f A Tech 2 can clear the DTC's.
Diagnostic Aids
Check for the following conditions:
f 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.
f The Fuel Pressure Sensor shares a 5 Volt reference
with the MAP sensor and TP sensor.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.
f The Fuel Pressure Sensor share a ground with the
MAP sensor and the TP sensor.
f Damaged harness: Inspect the wiring harness to the
EVAP vent solenoid and the fuel tank pressure sensor
for shorts to ground, shorts to battery positive, and
open circuits.
f Kinked, pinched or plugged vent hose: Verify that the
vent hose between the canister and the EVAP vent
solenoid is not restricted.
Check for charcoal particles. Refer to Carbon Particles
Removal from EVAP System before starting repairs.
Reviewing the Fail Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that causes the Diagnostic Trouble Code 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:
1. The Powertrain OBD System Check prompts the
technician to complete some basic checks and store
the freeze frame and failure records data on the
Tech 2 if applicable. This creates an electronic copy
of the data taken when the malfunction occurs. This
may assist in diagnosing the condition.
3. If a vent solenoid electrical malfunction is present,
the purge system will not operate correctly.
Repairing the electrical malfunction will very likely
correct the condition that set Diagnostic Trouble
Code P0446.
4. Checks the fuel tank pressure sensor at ambient
pressure.
6. Forces the fuel tank pressure sensor to re–zero.
7. Verifies that the fuel tank pressure sensor
accurately reacts to EVAP system pressure
changes.
9. Checks for a blocked EVAP canister.
13. Duplicates the Powertrain On–Board Diagnostic
test.