XC90 AWD L6-2.9L Turbo VIN 91 B6294T (2004)
The evaporative emission system (EVAP) valve is used to open/close the connection between the EVAP canister and the intake manifold. The valve
controls the flow of hydro-carbons (fuel vapor) from the EVAP canister to the engine intake manifold using the vacuum in the intake manifold. This
ensures that hydro-carbons stored in the EVAP canister are used in the engine combustion process.
The valve is an electro-magnetic valve which is powered from the system relay. When the valve needs to be opened, it is grounded internally in the
engine control module (ECM). The evaporative emission system (EVAP) valve is closed when in the standby position (open-circuit).
When the control module requests that the EVAP canister should be emptied (the hydrocarbons stored in the canister should be released into the engine),
the control module deploys the evaporative emission system (EVAP) valve by grounding it. The valve is grounded using a pulse width modulation
(PWM) signal, allowing the control module to govern the extent to which the valve opens and adapting the emptying of the canister according to how
full it is, engine speed (rpm) and load etc.
The engine control module (ECM) can diagnose the evaporative emission system (EVAP) valve. The valve can be activated using VIDA.
The evaporative emission system (EVAP) valve is close to the intake manifold.
Camshaft reset valve (Continuous variable valve timing (CVVT))
The camshaft reset valve controls the oil flow to the CVVT unit (camshaft pulley).
The valve consists of an electro-magnetic valve with a spring-loaded piston. There are slits in the piston which channel the engine lubricating oil to the
CVVT unit by moving the piston in the reset valve. The continuous variable valve timing (CVVT) unit turns the camshaft (the cam timing changes). The
direction in which the camshaft turns depends on the chamber in the CVVT unit which is supplied with oil (pressure). Also see Function See: Powertrain
Management/Computers and Control Systems/Description and Operation/Bosch ME7.01 Engine Management System/Function.
The system relay supplies the reset valve with voltage. The valve is grounded (control stage) in the engine control module (ECM). When the valve is
grounded using a pulse width modulation (PWM) signal, the oil flow in the valve can be controlled to the different chambers in the continuous variable
valve timing (CVVT) unit at variable rates. This allows the cam timing to be changed precisely and steplessly.
The engine control module (ECM) can diagnose the camshaft reset valve.
The valve is on the cylinder head above the camshaft with camshaft control.
Turbocharger (TC) control valve