How abs speed sensors works in nissan sentra?

Abs light usually caused by bad wheel speed sensor.
If cruise works but light is not on, replace bulb in cluster.

This link may be helpful.
Bob

https://www.google.com/url?sa=t&source=web&rct=j&ei=jVO4VK_hEMvbsAT83YDgCA&url=http://www.autopartswarehouse.com/shop_years/nissan-sentra-speed-sensor-2001.html&ved=0CDcQFjAA&usg=AFQjCNHmI3zYnmpPLAMrWGUYw4Hq3dw2tQ&sig2=NZHLkkBawd1OUJEZgAwLQQ

This code refers to fault detected in one of the wheel speed sensors. It doesn't mean that you have a bad wheel speed sensor (or other wise called an ABS speed sensor) but that the ABS module detected inconsistent data from one of your wheels. The sensor could be damaged but know that you could have another problem too. A loose wheel bearing, damaged harness, low tire pressure, or a problem inside the control module could be to blame. Let me know if that helps or if I can be of more help. Good luck.

are you sure it was the speed sensor.... speed sensor fail will also affect the abs.... now cam or crank sensor will put engine in limp mode.

Could be the speed sensor in the transaxle.

Probably your ABS brakes. Thats how they work, they pulsate so as not to lock up and go into a skid

Wheel Speed Sensor
What codes are you getting?

Vehicle Speed Sensor is IN the Transaxle-is your ecu indicating VSS circuit is open? Check out Nissan Forums.com If so, most likely, the sensor is bad or unplugged.Circuit includes sensor,wiring from sensor to the ecu,and the ecu itself.

The only way to know axactly what happen is with a diagnostic computer.
Because the ABS use a Speed sensor on each of the wheels.
Hydraulic selenoids on the ABS box or Module..
If the light is on. its mean the Anti Lock Brake System is inactive., You gonna brake like any car with no ABS.
I hope this information work for you.