My car has a servo that activates the EGR valve.

I need to check if it works, so I’m thinking of removing it and connecting power to the contacts and seeing if it moves. The question is, is it likely to be 12V or some other voltage? I’m assuming 12V…

Be careful, a lot of motor vehicle electronic systems work on 5 volts…

Do you know if you are getting voltage to the EGR servo? That would tell you if that part of the system is working…

If it is petrol you cold check the voltage to the Idle Air Control Valve which could be a stepper motor and will obviously need voltage to operate that. this may give you some reference as to what voltage you need to use.

I guess the first question is why do you need to check the EGR system?

What car & engine ?

Be very carefull , could have a 12 volt supply with a 0-5 volt signal or pwm signal .

It’s will also more than likely have a position sensor built in to it .

Best way to activate is with diagnostic equipment .

Why do you think it’s faulty ?

Why do you need to check it?

doent or you will turn it into a paperweight
Take it to a pro
Turn it on and off via computer
There normally 5volts pulse width modulated so 12volts DC will toast it

Egr probs are normally the valve choked up with carbon leaving the valve unable to shut resulting in pisspoor running and heaps of smoke
You can buy cans of egr valve cleaner or strip and bath in petrol or leave coated in Mr muscle oven cleaner overnight

Why check it? If a diesel, you most likely won’t need EGR to be working to pass the MOT, so you’ll probably never know if it isn’t (apart from getting slightly better fuel economy).

If its gummed up the car can smoke excessively, and it can cause flat spots and spurts in the power delivery.

I cleaned mine with carb cleaner and it sorted out some intermittent hesitation when accelerating gently.