First was my "engine check" light on my truck came on, I brought it in and it was a bad $100 senor that monitors a part that WAS working Fine! They wanted $200 for the sensor and labour, I just paid the $60 for them finding the problem and drove the truck for 3 years and finally the engine check light went out and that was 2 years ago.
Now My ABS light on my Van comes on some days and some days not. The Brake Pads and lines are all good the brake fluid is up with no leaks and the van stops on a dime. I,m not even bring it in to get looked at this time.
Sometime black tape over the warning light is the answer.