P0562: OBD-II code P0562 means the PCM has seen battery voltage fall below its minimum threshold — usually a weak battery or failing charging system.

Symptoms

• Check engine light is on; other electrical modules may set 'lost communication' codes during voltage sags.
• Dim headlights, slow crank, and dashboard warning lights that flicker on start-up.
• The vehicle may not start at all if the voltage falls low enough, or may stall unexpectedly under electrical load.

Common causes

• A weak or aged battery unable to hold voltage under load — always test the battery first with a load tester.
• A failing alternator with worn brushes or an internal diode failure, undercharging the electrical system.
• Corroded battery terminals, loose ground straps, or a damaged main power feed adding resistance to the supply path.

What to do?

Load-test the battery and confirm charging output stays between 13.8 and 14.5 V at idle and 2,000 RPM. Clean and torque battery terminals; inspect the main engine and chassis ground straps. Replace battery or alternator if either is out of spec, then clear the code and monitor.