Lexus SC430 :: Brake / ABS And VSC Lights Powered On

2002 SC430, 150,950 miles.

Had new front brake pads, re-surfaced rotors, new windshield fluid level sensor installed, 4 x wheels balanced and rotated on 8/11 at Lexus Dealer. Picked it up 8/13, drove 30 miles and it sat 8/14-8/16. Drove to work on 8/17, and on the 18 mile freeway trip home yesterday, the Brake and ABS dash lights came on as I was making a gradual left turn with damp roads.

Thought nothing of it initially, thought my knee had hit the e-brake as mine is very touchy and as long as you pull the release, the light goes away. Not this time. The Brake and ABS lights were on for 4 minutes, then eventually the VSC and VSC OFF dash lights also came on. Steering became difficult, checked brake fluid (ok), checked power steering fluid (ok). No leaks underneath, all fluid levels were just checked on 8/11 and were fine/topped off.

Parked it, set up an appointment and just dropped it off this AM. I've read brake booster, speed sensor, alternator, skid control unit .

I am hoping it's just the alternator, which makes sense with the difficult steering and the lights going on one by one. If the alternator isn't outputting enough volts, those lights will trip. I've had all O2 sensors recently replaced, other standard preventative maintenance done (timing belt, thermo, etc). I'm just hoping it's something manageable and not something that makes me wonder if the repair is worth it (vs the value of the car)...

There are no CEL lights, just the above (no codes to my knowledge).