System Voltage Malfunction
A general fault in the system voltage seen by the ECU — value implausible, missing, or unstable but without crossing the specific thresholds of P0562 (low) or P0563 (high). Often appears intermittently with a marginal alternator or weak battery.
Affected components
- Battery
- Alternator
- Battery cables
Common causes
- High likelihood: Charging system marginal (aged battery or alternator)
- Medium likelihood: Corroded battery terminals or ground strap
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.