Evaporative (Evap) Emissions Canister Purge Valve Check; Circuit Description; Diagnostic Aids - Isuzu 2000 Trooper Workshop Manual

Evaporative (EVAP) Emissions Canister Purge Valve Check

Circuit Description

Canister purge is controlled by a solenoid valve that
allows manifold vacuum to purge the canister.
powertrain control module (PCM) supplies a ground to
energize the solenoid valve (purge "ON"). The EVAP
purge solenoid control is turned "ON" and "OFF" several
times a second. The duty cycle (pulse width or "ON" time)
is determined by engine operating conditions including
load, throttle position, coolant temperature and ambient
temperature. The duty cycle is calculated by the PCM
and the purge solenoid is enabled when the appropriate
conditions have been met:
D The engine run time after start is more than 60
seconds.
D The engine coolant temperature is above 30°C
(86°F).
D The fuel control system is operating in the closed-loop
mode.
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
The

Diagnostic Aids

D Make a visual check of vacuum hoses.
D Check the throttle body for possible cracked.
D Check the malfunction indicator lamp for a possible
mechanical problem.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.
1. Check to see if the solenoid is open or closed. The
solenoid is normally de-energized in this step, so it
should be closed.
2. This step checks to determine if the solenoid was
open due to an electrical circuit problem or a
defective solenoid.
3. This should normally energize the solenoid, opening
the valve and allowing the vacuum to drop (purge
"ON").
6E–123
D06RY00128