ABS and TCS dash lights going on

99 Pontiac Montana with 80K miles. for some reason the TCS and ABS lights keep staying on at random intervals. Sometimes I can turn it off and restart to reset it and they will stay off, other times I can not. I have taken it in and the diagnostic computer has not been able to find what is causing it or locate any history codes. Anyone know what is going on?

I have a 2001 Montana and had similar problems. It ended up being a wheel speed sensor. It is actually the sensor and bearing assy all in one. I lived with my lights being on for the longest time and then I started getting a thugging sound from that side. (Thats when I found out about it being all one unit). It costs about $800.00 installed but fixed the problems.

I had the same on my 2000. Quick fix before dealer is that it is getting moisture in connecter at wheel spindle. I removed the wheel, turned the steering wheel to left/right to see abs sensor connector. The connection is not protected. Unclip connector, spray with wd40, reclip. For the rears, no good way to unclip, so spray thur the hole in axle to fix. worth a shot of WD before major service.