Powertrain
generic / SAE
P0561
System Voltage Unstable
The ECU monitors battery voltage and detects unstable behaviour - rapid fluctuations beyond what current load changes explain. Typical causes are a failing alternator, loose battery terminals, weak battery, or a heavy load (radiator fan, glow plugs, heated screen) drawing voltage down briefly.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 61
Possible causes
- Alternator regulator failing high
- Battery weak or terminals loose medium
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–800 €
- Estimated time: 0.5–3 h
- Component: alternator
- Component: battery
- Component: main supply wiring
- MIL / check engine light
Sources
References
sae:J2012