2006 Sonata Electrical? Mystery

I have a 2006 Hyundai Sonata that in winter does very strange things, almost ghostly. While driving, headlights flicker on and off, the dash abs and esc warning lights go on, and rpm’s shoot up and stay there as if it downshifted by itself. I have to pull off the road and turn the car off.

Further, three different times I shut the car off and then nothing would work, including not being able to start the car. After it sits a while it then seems to reprogram itself and works properly.

I contacted Hyundai, and they only said bring it in and pay to diagnose it. But there appears to be no fix, as many have reported electrical problems for this model on the internet.

I hope you can help because this is scary and dangerous.

Thanks, Lauren


How old is that battery?

Are the battery cables and terminals heavily corroded?

I would also have the charging system checked out

Along with cleaning the battery connections check for a loose connection between the battery and the power panel under the hood.

“rpm’s shoot up and stay there as if it downshifted by itself”

Does the engine actually speed-up?
Is this a case of just the tachometer suddenly registering higher RPMs while the engine behaves normally?

Clarification, please…