During highway driving, my car showed a "charging system failure" warning message. The light came on and went right back off. I checked the voltage which read 13.75. I had the battery and the alternator tested. Both checked out good although the battery did have some corrosion on the terminals which was cleaned up. Over the next couple days upon starting, the voltage read low 13's. It quickly climbed to mid 14's. Within 2-3 miles the voltage began to fluctate between mid 12's to mid 14's. I had a new alternator installed. The day after installation, the same problem started in again. Any idea what the problem is?
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I am having the same problem. My car wouldn't start one day. The battery wouldn't take a charge. I put in a new battery. Everything worked fine. Then I noticed the voltage on the DIC was going down again. Sometimes it would go back up, especially when I first started it. But then it would come back down. I had auto zone check the alternator, and they said it was bad. I replaced that as well with a new one (not a rebuilt). Everything was good again. But a couple days later the voltage was doing the same thing. I have been researching this, and we don't seem to be alone. I haven't found an answer yet. The regulator is in the alternator so it shouldn't be that. I will keep looking. Maybe its a bad cable?
