Questions and Answers

Valves, Solenoids And Actuators Q. Dear Mr Ciulla, Could you be kind to let me know how many (different) valves, sensors, relays, actuators and ECU's in total in a car or could you recommend the web sites where I can obtain such information and the related? I am wondering if all valves in modern cars are solenoid type. Thanks, Best Regards, Tom

A. Depending on the year, make and model of vehicle, there can be up to 400 different valves, sensors, relays, actuators and ECU's in a vehicle.

But to address your inquiry, All the electrically controlled valves, with a rare few exceptions, are of the solenoid type. They all use a coil of some type to withdraw or extend a plunger that is attached to whatever needs to be moved. And by controlling the amount of voltage applied to the coil, you can get the plunger to move in increments.

The fuel injector in your car is the most common type of solenoid used in a fuel injected engine.