A mechanic informed me that I could reset the codes on my truck by unhooking the battery cables and clamping the positive and negative together for 20 minutes. My truck is a diesel, therefore having two batteries. I am an idiot and when I went to hook up the one side, I forgot to unclamp the other side thus leaving the positive and negative terminals hooked up together. I quickly pulled it back off, but sparks flew and now my truck says that it has a low battery voltage and is in battery saving mode. What did I fry?