P0442

Detection Condition:

Test Procedure - Part 1:

Test Procedure - Part 2:

Step 1 - 5:

Step 6 - 10:

DESCRIPTION
The evaporative system reduces hydrocarbon emission by trapping fuel tank vapors until they can be burned as part of the incoming fuel charge. Evaporating fuel is stored in a charcoal canister until it can be flushed into the intake manifold.

The evaporative control system is made up of the following components:.
1. Fuel tank which can be completely sealed from outside air.
2. Fuel tank pressure sensor.
3. Fuel/vapor separator which returns raw fuel to the fuel tank and allows only vapors to flow to the canister.
4. Canister close valve which seals the system for testing.
5. A canister filled with granular charcoal.
6. Purge control solenoid valve.

In normal operation, the purge control valve opens and closes depending on throttle angle and intake manifold vacuum. When it opens fuel vapors are flushed from the canister and drawn into the intake manifold. To avoid a vacuum build-up in the canister, the canister close valve in normally held open to allow fresh air to replace the vapors drawn into the intake manifold.