To me this may be some electrical fault, but where? Ask the shop to get the OBD readings too. The lights are usually from some central computer board but you would have to have the service manual to know this.
For me, I have shops that do great work but not the lowest price. I know folk that shop around and that's a fine idea but you get the idea here. You need a shop that can fix this.
I am having trouble with my 2006 Toyota Rav4 V6 with 3.5L engine and I believe it is a base model with a third row. Suddenly the check engine light, traction control, and VSC lights all popped on at once. I had my alternator, serpentine belt, water pump, engine coil P0355, and gas cap replaced but all three lights are still on. Today as I was driving with all three lights still on, the check engine light began to start flashing incessantly then my car started shaking as I stepped on my brakes and was lagging to speed up as I stepped on the gas. Any ideas on whats going on? I have already spent quite a bit of money attempting to fix this problem but it seems to be getting worse, any ideas are appreciated.