Wheel Speed Sensor

[vpmick]

I took my 2006 MCS to the dealer today due to abs light, tps light and service engine light coming on intermittently. The dealer said I needed to replace found a fault for LF Wheel Speed Sensor and ordered a Pulse Generator. Does anyone know what might cause this to happen, what happens if I don't replace to Pulse Generator and is this a DYI project?

[bad venge]

It likely will not have ABS and the lights will stay on
It can be hit by rocks ect or just died hard telling without the car to look at