What's happening to my 2016 Hyundai Sonata Hybrid?

I tried to turn on my 2016 Hyundai Sonata Hybrid, and my dashboard lit up like Christmas. I’ve never seen this before. It says, “Stop Vehicle. Check Brakes” and all the lights are on. My front and rear lights are flickering. When I try to turn it on again, it says no key detected. I just replaced the batteries in the FOB and took my car to the dealer for maintenance last month for coolant issues. Any ideas on what this new problem could be?

When did you last replace your 12V battery?

Mia said:
When did you last replace your 12V battery?

Or checked the battery terminals.

James said:

Mia said:
When did you last replace your 12V battery?

Or checked the battery terminals.

You guys were spot on. I’m using an 8-year-old battery. I connected it to a new power source, and the car came alive again. Thanks! I’m going to get it replaced.

@SonataSavvy1
Great! Make sure they check the terminals when they install the new battery, but it’s mostly a GM issue for them to corrode early. Good luck!

@SonataSavvy1
Awesome! Thanks for updating us. It’s rare to see that around here.

@SonataSavvy1
Glad to hear that! It’s nice to see the forum being helpful for people with issues.

All those warning lights usually mean your battery needs to be replaced. I HATE that this is the case across all car brands. It’s super scary when it happens!

I had a similar issue with my 2023 Sonata. While driving, I’d lose all power, and every light would come on. The car could only go up to 5 mph. After taking it to two shops, the second one said my wiring harness failed. I had less than 10,000 miles on it, but you should still have a warranty. Just sharing my experience.

Has it been raining? Maybe the brakes got wet. That happened to me with my 2021 Sonata Hybrid once!

Nathan said:
Has it been raining? Maybe the brakes got wet. That happened to me with my 2021 Sonata Hybrid once!

Your wet brakes caused all the warning lights to turn on?

This could be related to an engine problem.

What’s happening is you bought a Hyundai.