Corrado V6-2792cc 2.8L DOHC (1992)
Charcoal Canister By-Pass Valve: Description and Operation
OPERATION
The flow of fuel vapor is determined by the ECM, depending on engine load, speed, and temperature. The valve is completely open at full throttle
and completely closed during deceleration. The ECM controls the ground circuit. Voltage (12 VDC) is supplied by the Motronic power supply
relay.
When no current is supplied to the valve, it remains in the open position. The valve is closed (100% duty cycle) when the engine is started cold.
A spring operated check valve closes when the engine is off to prevent vapors from entering the intake manifold.
MALFUNCTIONS
If the EVAP valve circuit is interrupted, the valve remains full-open. This could lead to rough idle and hesitation.
The valve is monitored by the ECM for short and open circuits.
