it switches on for about 3 seconds, then it switches off.

it sounds like a high-pitched "microwave" type of sound.

i hear it when i come to a stop. you have to have the stereo OFF in order to hear it.

does anybody know what it is?

Thanks.

 

It's the secondary Air injection pump. It is mounted under the left headlight. Usually you will hear it only on cold starts. Occasionally, the PCM will power up the pump to do a function test as part of the OBDII self diagnostic monitors.

 

Catching the tail end of the rad fan cycling?

 

I hear it at least once every day, which is why it worries me.

If it is the secondary air injector pump, am I supposed to hear it this often?

Is the secondary air injector pump only supposed to turn on for 3 seconds?

I'm more paranoid because i ran over a tire a month ago and am afraid I caused some damage to some parts. My hood doesn't close anymore unless I push down on it really hard (I'm aware it may bend the aluminum hood, but I had no choice since I can't drive the car without the hood secured.

 

If you hear it everytime you start the car and the coolant temp is below 135, it is normal. The secondary air pump is constantly monitored, if the CEL is off, there is no problem with it.

Are you dropping the hood from about waist high? All S2k's have are known for being difficult to shut the hood. The drop method works the best.

 

I hear mine come on sometimes if i leave my car running. Then sounds kinda like a little blow off valve

 

That wasn't very nice, So I've removed your post.

 

Yeah I agree with slows2k or xviper. it's either the secondary air injectioni pump, or most likely the radiator fan. When it turns off/on do you hear a "tick" as if a switch was flipped? If so I believe that's the radiator fan.

 

Yes, I hear a tick when it turns on...its on for 3 seconds, then i hear a tick and it turns off. If it is the radiator fan, why does it constantly turn on for only 3 seconds and turn off?

Is this normal?

 

Next time you start the car, listen BEHIND you. It could be the fuel pump doing its initial cycling on to pump up the system. In fact, if you have someone else key the ignition on and you listen at the fuel fill hole (with cap off), you should hear it clearly. Turn off your stereo and heater fan first if these are on.