Possible Causes
Engine oil level low
Engine oil contaminated
Incorrect oil filter
Insufficient oil pressure due to a mechanical failure in the oiling system
Faulty Variable Valve Actuator (VVA) Assembly
الأسباب المحتملة
Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
الأعراض المحتملة
Description
Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled hydraulic link between the camshaft and intake valve, allows for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.
The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event, the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The VVA Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting the lift and duration of the valve opening.
The Diagnostic Trouble Code (DTC) will be set when the PCM measures the time needed to turn on the VVA Solenoid. When the PCM recognizes that the VVA Solenoids switch off time is too fast or too slow a fault is set.
