P0563

What P0563 means

Your car's computer keeps an eye on the voltage coming from the charging system. This code means it saw voltage higher than it expects, usually above around 15.5 volts for long enough to flag it. The normal range with the engine running is about 13.5 to 14.7 volts. Above that, the alternator (or the voltage regulator that controls it) is overcharging the electrical system.

Is it safe to drive

Short term, yes, you can usually still drive it. But sustained high voltage cooks things it shouldn't. It can shorten the life of the battery, fry bulbs, and stress modules and sensors that aren't built for the extra voltage. If you notice the battery warning light on, a burning or hot electrical smell, dash lights flickering or overly bright, or the battery case looking swollen or leaking, stop driving it and get it looked at right away. Otherwise, get it checked in the next week or two rather than today.

Common causes, most likely first

The most common cause is a failing voltage regulator. On most cars built in the last 15 years or so, the regulator is built into the alternator, so people often just say "bad alternator." On some vehicles, though, especially GM trucks and some Fords, the regulator is a separate part or controlled by the engine computer through what's called a smart charging system, and the fault can be in that wiring or in the module telling the alternator what to do, not the alternator itself.

Other causes include a bad connection or corrosion at the battery terminals or the main ground strap, which can make the system compensate with higher voltage. A battery that's failing internally can also confuse the charging system into overcharging to try to keep up. Less often, it's a wiring problem between the alternator, the battery, and the body ground, or on newer cars, a fault in the module that manages charging voltage based on battery temperature and state of charge.

What diagnosis involves and rough cost

Diagnosis starts with a voltage check at the battery, both at idle and under load, along with a look at the wiring and grounds. We'll also pull codes from other modules if there are any, since a charging problem can trip codes elsewhere too. On vehicles with a smart charging system, we check whether the computer is actually commanding high voltage or whether the alternator is ignoring the command, since those point to different repairs.

Cost depends heavily on what we find. A corroded ground or terminal cleanup is inexpensive, often under $150 with labor. Alternator replacement varies a lot by vehicle, roughly $400 to $900 parts and labor depending on the car and how hard the alternator is to reach. If it turns out to be a separate voltage regulator or a wiring repair, cost falls somewhere between those. We won't know which one you're dealing with until we test it, so we'd rather check first than guess and swap the alternator on assumption.

Generic OBD-II guidance — manufacturer-specific codes and causes vary by make, so always confirm against your vehicle. A code identifies a system or condition; it does not, on its own, prove which part has failed.