HomeTrouble CodesP0562

P0562 — System Voltage Low

Generic OBD-II · all makesPowertrain (engine & transmission)

P0562 means the powertrain control module (PCM) has detected that system voltage is below the expected threshold for normal operation. The code usually points to a problem in the charging system, battery, or the wiring that feeds them, rather than a fault inside the computer itself.

Symptoms

What causes it — most likely first

1. Weak or failed battery

A battery with low capacity, a shorted cell, or high internal resistance cannot maintain system voltage, especially under load. This is the single most common trigger for P0562.

2. Faulty alternator or voltage regulator

If the alternator cannot produce enough current to recharge the battery and power vehicle systems, system voltage drops below the PCM threshold while driving.

3. Corroded, loose, or damaged battery cables/connections

High resistance at the terminals or along main power and ground cables reduces effective voltage reaching the PCM and other modules.

4. Excessive parasitic electrical drain

A component that stays on after the ignition is off can discharge the battery overnight, causing low voltage at the next key-on event.

5. Wiring or fusible-link faults in the charging circuit

Broken, chafed, or corroded wires between the alternator, battery, and power distribution can create voltage drops that set the code.

6. PCM failure

A faulty PCM misreading system voltage is possible but genuinely rare; it should only be considered after the entire charging system, battery, and wiring have been proven good.

How it's diagnosed

  1. Measure battery voltage with the engine off (should be about 12.4–12.6 V for a fully charged battery) and with the engine running (typically 13.5–14.8 V).
  2. Inspect and clean battery terminals, clamps, and main ground connections; verify they are tight and free of corrosion.
  3. Perform a battery load test and an alternator output test to confirm each component can deliver rated current and voltage.
  4. If the battery repeatedly goes low, perform a parasitic draw test with the vehicle asleep to identify a stuck relay, module, or accessory.
  5. Check the alternator/battery power and ground cables, fusible links, and related connectors for damage, melting, or voltage drop.
  6. Only suspect the PCM after all charging-system, battery, and wiring tests pass and the voltage reading at the module differs from a known-good meter reading.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Is it safe to keep driving with P0562?

It is not recommended. Low system voltage can cause stalling, loss of power steering or braking assist on some vehicles, and can leave you stranded.

Should I replace the PCM for P0562?

Usually no. P0562 is most often caused by the battery, alternator, or wiring. PCM replacement is rarely the correct fix and should only be considered after the entire charging and power-distribution system is verified good.

Can a brand new battery still cause P0562?

A new battery itself is unlikely to be faulty, but loose or corroded terminals, poor grounds, or a failing alternator can still produce low system voltage even with a good battery.

Why does the code return right after I clear it?

The underlying voltage problem has not been fixed. Clear the code only after the battery, alternator, cables, and any parasitic draw have been tested and repaired.