check engine light, vsc, plus yield

[Ariboo22]

• 3 months ago my car died and I was able to pull off the road. My dad told me my alternator, I wanted to make sure it wasn't my battery so we took it to auto zone.  Sure enough, the battery was fine practically bran new. I got the alternator replaced by my bother's neighbor who's a mechanic ($200.00). My bother took care of it, come to find out he didn't replace it with the orginal lexus part. The mechanic noticed something with the water pump, I took it to a family mechanic this time, the job was too big for home repair. My water pump was replaced with brand new orginal lexus parts ($990.00) I thought that was the end of my misery. I drove it home immediately the check engine light, vsc and yield ligts is back on my bashboard... I finaly decided to take straight to the dealer. ($135.00) to run diagnostics? They sent me home with my car and said the car needed a system update which took away the warning lights.  Still... it didn't resolve my problem. I've been doing my own research and reading lots of forums online. I took my car back to Lexus and said I believe there's something wrong with my car. This time my car wasn't driving right. there was some mis firing with the system. Id step on the gas and my car would move very slow and the engine made a rubbing the engine sound. I told my dad about my problematic car. He takes out my battery and the lights disappears again. I thought this time he fixed the problem only a day driving it all the warning signs comes back on. I tell Lexus id bring the car back in for a second opinion. (600.00) they replaced the some wires... stated that they were able to see the damage wires. my advisor called and said it'll cost me about (600.00) I told him to fix it....... smh, only after 30mins driving my lights are all back Warning yield, check engine and vsc. CAN SOMEONE RELATE, IF SO WHAT WAS THE PROBLEM AND YOUR SOLUTION. I SPENT SO MUCH MONEY I DONT WANT TO SPEND ANY MORE.
   

[1990LS400]

I think all you can do is to head back to the Lexus dealer or find an independent repair shop that specializes in Lexus or Toyota vehicles.  Maybe have autozone read the codes again and tell us what they are.  Countless issues can cause the Check Engine and VSC warnings.