Wastegate Solenoid: Description and Operation

Wastegate Solenoid Circuit:

The turbocharger wastegate solenoid is a duty cycle type solenoid. The ECU can open and close the solenoid several times per second, thereby controlling the turbocharger boost pressure very accurately. When the ECU detects engine ping, via the knock sensor, it will first retard the ignition timing to reduce the occurence. If retarding the timing does not significantly reduce the pinging, the ECU will the energize the wastegate solenoid. When the solenoid is energized, the vented port of the wastegate solenoid is closed for a certain period of time. This allows boost pressure to act upon the wastegate diaphragm, opening it. When the wastegate is open, some of the exhaust gas bypass' the turbocharger impeller, thereby lowering boost pressure and engine ping.