Yesterday my ABS and traction control light came on together for no apparent reason. When I restarted the car, they were off and have not come back on again (?) Is this a concern?

thanks

FIRST!

i wouldn't worry.

do you know why those lights come on i mean what can trigger them to come on...

If they are off and staying off, don't get worried. The usual causes to that would be a failing wheel speed sensor (read new hub). If it happened once, call it a glitch and smile if you don't see it again.

thanks, it did come on again two days later. Is that an expensive repair?

The toughest part is identifying which hub or part is bad. That might take a trip to the dealer and their usual $100 diagnostic fee. Then the part is around $80-100 (non dealer) plus labor.

Easy to swap on our cars though.

Bah, prolly just some crud got between the magnet and the hub teeth.

I just replaced both wheel speed sensors (one went, then the other) $157 each from NAPA.

When those two specific lights come on together, the first thing to check is your brake fluid level. If there isn't enough fluid in the reservoir to support ABS cycling, you'll get those two warning lights together. (Yeah, it freaked me out when I saw those light up on mine; it was a great relief when the factory manual pointed me to the fluid level as a first step.)

As for why you only got the lights that one time (or just occasionally), you may be just on the brink of triggering the warning light, to the point that it matters what angle the car is tipped at when you park it, as far as whether the internal float will trigger the warning switch.