97 c280 ABS problem. Code C1102
 

My ABS light is on and while it is turned on the car will only drive in 2nd gear making things incredibly difficult. I took the code for the car and it gave me C1102 which I believe is the Left Rear Sensor. Is this a speed sensor or a wheel sensor and is there a difference?

Anybody know how I should proceed? Are there any tips for making the ABS light go off? Is it possible to DIY this problem?