Hyundai Repair Questions? Ask a Mechanic for Answers ASAP
Hello...welcome and thank you for using Justanswer.
Well as the first step you need to check the vehicle charging system and the battery .
It sounds like when you step on the brake you are draining the voltage needed to the engine sensors/electric parts to work.
First step, check for the alternator performance ,make sure is charging above 13.5 volts.
The battery ,you will need to perform a load test, this is the only way you can find out if all the cells are good, other wise ,you may have the 12 volts there but if a cell is bad ,it may fail under a load ,like when cranking the engine.
Let me know.