traction controll light on and service light 2 ?

[motfree]

2 weeks ago my box give up on me so i bought a new 1 an i have just had it fitted
i picked the car up yesturday and noticed that once i reach about 20mph the service light and traction controll light comes on... iam fairly sure that a sensor might have been left off but i dont have a clue where to look
wondering if any1 has any ideas

thanks