P0562: Low system voltage measured while the engine is turning

P0562 is a system-voltage-low code. The cited GM engine-controller monitor detects battery-system voltage at or below nine volts while engine speed is at least 400 rpm. It also requires run/crank voltage above five volts and the diagnostic enabled.

Preserve the operating state

Those prerequisites distinguish this test from an arbitrary battery reading with the vehicle asleep. A low measurement during the monitored running-speed state has a different context from voltage during initial starter engagement or a battery disconnected for service.

The controller counts 400 failures out of 500 samples at 12.5 milliseconds per sample. A brief present-day voltage check may miss the episode that filled that counter. Record fault timing and voltage history before deciding which electrical component needs attention.

The code does not identify the source of the loss

The page confirms low system voltage but does not distinguish battery condition, charging behavior, a supply connection or the controller's measurement path. Use the applicable electrical diagnostic procedure to locate the reason for the low reading rather than selecting a battery or generator from the code alone.

This row is Type C, one-trip and explicitly has no emissions malfunction-lamp request. Lack of that lamp therefore does not mean the voltage monitor passed. Verification should show stable voltage during a completed eligible test and resolution of any related supply symptoms or faults.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 331. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.