Pontiac Repair: brakes,abs, volt ohm meter, wheel speed

Question
recently my montana{2002} has had the abs come on while driving do not have to be braking.and it sounds like a pump running inthe vehicle also dont have to be braking for about 3 seconds  at a time this doesnt happen everytime you drive it but is becoming more frequent. there is no loss of preformance when braking any help would be appreciated thaks

Answer
Hi Dan:

I take it no service vehicle soon.trac off or abs lamps are on? If not My guess it you have a wheel speed sensor that is dropping out when you come to a stop. The sensor is either cutting out,or slowing down faster then the other 3 wheels and you are getting a flase ABS stop occurance. It's a common issue with the vans It's a matter og which of the three is doing it. If you handy and have acces to a volt ohm meter can unplug each sensor and check the restance across the 2 wires of the sensor the resisitance should be anywher between 800-1400 Ohms and laos check one of the leads to the body/chasis ground the meter should only read OL meaning there is no short in the sensor to the chasis. Good luck :)