Etended pump/compressor in rear running...

[RedRagTop]

Extended pump/compressor in rear running...

Hi all. When I have used the brake simetimes the compressor or pump (not fuel pump) located somewhere the rear will run on sometimes for up to 10 seconds or more. What is the sound coming from and why does it stick on occasionally?
Opinions?

 

[rrhayden]

The sound is comming from the ABS/ASR pump. It is located in a compartment directly behind the drivers seat, under the carpet. Why it is running , I do not know. It should only come on when the anti lock break is working or the asr is active.

It does do a self check, when you first start and move the car.

 

[Magmotor]

This may help out a little.

 

[RedRagTop]

OK, thanks. So, that means that after a moderately heavy brake application the pump runs a bit to bring pressure back up or something?
You're right about the self-check, I hear it do that at the same point in my driveway each time I drive...
What is the ASR again?

 

[rrhayden]

The only time it should run is when the anti-lock is operation as in you have the tires locked up and you are sliding. The ASR is the electric system to prevent skids, it activates if you are applying too much power in a turn. It will cycle the brakes and force the peddle off the gas.