Why does my TCS and ABS lights come on while

Agree with these solutions as posted. However just to add - on some vehicles the TCS light will illuminate momentarily in conditions of poor traction e.g if you are going up a snow covered hill and the vehicle hits a slippery spot the TCS light may illuminate.

However if you are getting these lights illuminating together it is essential that you have the car checked out as a priority as these are not systems to take chances with.

Traction control might be defeatable (ie: able to be turned off) but abs isn't. The lights aren't supposed to automatically come on come on when driving. The lights will illuminate for a few seconds when you start the car, and then go off after three or four seconds. If the light comes on there is a fault in the system. The abs computer will have to be scanned and the fault diagnosed based on the codes you retrieve. Most abs codes are speed sensor related.

you have a problem with probably your abs system that is also causing your traction control system to be inoperative

no theres a problem with the abs, when abs doesnt work it turns on both those lights, you have to have computer scaned to get codes to diagnose the problem, it maybe just a wheel sensor. you cant turn it on or off, but you can still drive like that you just wont have abs trac-control when lights on computer shuts it down, so its like you shut it off, if you dont need it then dont fix it,wont affect running of engine .good luck.