P0562: The electrical system voltage is running too low
System Voltage Low
System voltage is low, often from a failing alternator, battery or connection. The engine or electronics can cut out without warning. Get it checked today. If warning lights pile up or the lights dim, pull over.
Stop driving and get help if
- The check engine light is flashing
- The temperature gauge runs high, or you see steam (overheating)
- The car loses power, hesitates badly or stalls
- You smell burning or see smoke
- A brake warning light comes on, or the brakes feel different
Pull over as soon as you can, turn the engine off, and call a tow or roadside help.
What it means
P0562 means the PCM detected battery voltage below a threshold, typically around 10 to 11 volts, for a defined period. The car needs roughly 13.5 to 14.8 volts when running, supplied by the alternator. When it falls short, everything electrical is underpowered. The code is commonly set while idling with loads like AC, headlights, and blower on, when a failing alternator cannot keep up. The underappreciated trap: a loose alternator belt or a corroded battery terminal can mimic alternator failure. Check those first before condemning the alternator.
Common causes
- Failing alternatorCannot maintain charging voltage under load. Output drops below the threshold at idle with AC on.
- Loose or worn alternator beltThe belt slips under load and reduces alternator output. Cheaper and faster to check than the alternator itself.
- Corroded or loose battery terminalsResistance at the terminal causes voltage drop. Clean first; the fix may be free.
- Weak or failing batteryA battery that cannot hold charge pulls voltage down, especially at cold start.
- High-draw electrical faultA short or a module stuck on can drain the system faster than the alternator can supply.
What the fix could involve
From the cheaper fix to the bigger one. Prices depend on your car, your area and the shop, so ask for a written quote that names the part and the labor before you approve it.
- Battery terminal cleaning
- Alternator belt replacement
- Battery replacement
- Alternator replacement
Symptoms
- Check engine light on
- Battery warning light may also be on
- Dimming headlights or interior lights at idle
- Electrical components behaving erratically
- Engine stalls or is hard to start
What to do next
Use a multimeter to check battery voltage with the engine running. It should read 13.5 to 14.8 volts. At or below 12.6 volts with the engine running, the alternator is not charging. Before replacing anything, check the belt for tension and condition and clean the battery terminals. A free battery test at any auto parts store can confirm the battery health.
Lewis reads P0562 alongside any other low-voltage codes from the computers it can reach, so you can see whether the charging problem is affecting more than one system. Get Lewis on the App Store or Google Play.
Related codes
FAQ
- Will low voltage damage the PCM?
- Prolonged low voltage can corrupt PCM memory and damage sensitive electronics. This is another reason to address it quickly rather than driving on it.
- Why does the voltage drop only at idle?
- At idle, the alternator spins slower and produces less output. When AC, lights, and the blower all run at idle, a weakening alternator cannot keep up.
- My battery light is not on. Can I still have P0562?
- Yes. The battery light has its own threshold, which may be lower than the PCM's threshold for P0562. You can have low voltage detected by the PCM before the battery lamp activates.
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