OBD-II · Engine and powertrain (P)
P0562
System voltage low
What it means
The ECU's supply voltage has dropped below its minimum.
Symptoms
- battery warning light
- start-stop stops working
- slow cranking or no start
- dim lights or electrical glitches
- engine warning light
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | weak or aged battery |
| 02 | alternator not charging (worn brushes, regulator, freewheel pulley, belt) |
| 03 | poor battery or earth connections |
| 04 | parasitic drain flattening the battery |
| 05 | new battery not registered where the battery management requires it |
What to check, step by step
- 01Measure battery voltage with the engine off (about 12.4-12.7 V when charged) and running; note that smart charging on modern cars varies the voltage deliberately
- 02Test the battery with a conductance or load tester; start-stop cars need the correct AGM or EFB type
- 03Clean and tighten the battery terminals and the main engine and body earth straps
- 04Check the alternator belt, tensioner and freewheel pulley
- 05Check the alternator control wiring (single wire or LIN bus on many modern cars) and the battery sensor on the negative terminal
- 06After fitting a new battery, register or code it where the car's battery management requires it