Toyota Repair: Lexus VSC + trac off lights

Question
Hi,
I hope that you can help with Lexus question as I understand engines are same as Toyota. Car is 2002 ES300,about 148Kmiles.It was working fine except I had alternator replaced, not by dealer. When I picked car up, as soon as I started to drive car, VSC lights+trac off lights came on, stayed on. I left the car with the same mechanic for 3dys. He said that his replacing the alternator had nothing to do with the lights,he couldn't find out what problem was, it was OK to drive with the lights on so I should take it to dealer. Obviously, any work by dealer is expensive. I bought the car used in 2009 and I remember those lights coming on in 2011 and I had to replace catalytic converter, think it was recalibrated also and I can't remember any else major that was done. It's been fine since but I also don't drive it as much as I used to. I checked the trac off button in car, checked tire air pressure but the lights are still on. Car was inspected on 10/31 at Sears, he said he didn't see anything (it passed). I took car to Autozone for them to check engine lights, said they can't get code since the check engine light is not on. Car drives OK.I'm planning to drive about 1200miles at Thanksgiving to be with family so want to make sure I don't get stuck on the road-or cause damage to the car. Do you have any idea what could be wrong or do I have to just suck it up and pay at least coupla hundred dollars just for the dealer to check it out? Any suggestion welcome and appreciated.

Answer
Hello, the reason Autozone could not see any codes is because their scanner only checks engine codes, these codes are for the vsc/trac lights turn on is that there is a problem detected with the skid control system, if the car drives normally it is ok to drive this way except it will not have skid control or anti lock brake functions. I would be interested just what codes are stored so I can better advise you, in the meantime check fuses under the hood, it's possible a fuse blew during the alternator replacement, also check fuses on the inside fuse panel, try to locate a repair shop that charges less than the dealer to get those codes and then let me know the code numbers. I will be in a better position to advise what to do.