P0562 - System Voltage Low
P0562 means system voltage dropped below the expected range. The fault is usually found by proving whether the battery cannot hold charge, the alternator cannot maintain output under load, belt-drive slip is reducing output, or resistance in the battery, ground, starter, or charging-cable path is pulling voltage down.
Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.
Low Voltage Diagnostic Path
Separate battery capacity, alternator output, belt drive, and cable voltage drop before replacing parts.
Inspection Priority
- Verify battery voltage and load-test results first.
- Inspect cable voltage drop and grounds before replacement.
- Confirm starter command or charging output before pricing parts.
Code Overview
P0562 means system voltage dropped below the expected range. The fault is usually found by proving whether the battery cannot hold charge, the alternator cannot maintain output under load, belt-drive slip is reducing output, or resistance in the battery, ground, starter, or charging-cable path is pulling voltage down.
Common Causes
- Weak battery that no longer holds proper charge under load
- Alternator output failure when headlights, blower motor, AC, or other electrical loads are applied
- Loose grounds, corroded battery terminals, or charging-cable voltage drop
- Serpentine belt slip, weak tensioner, or pulley issue reducing alternator output
- Parasitic drain confusion creating repeated low-voltage or no-start symptoms after parking
Symptoms
- Slow cranking or intermittent no-start
- Dim lights or unstable electrical accessories
- Battery warning light or repeated dead battery complaints
- Multiple low-voltage communication or module codes
Diagnostic Steps
- If voltage is mostly low at idle, inspect alternator output, belt condition, belt tension, and pulley behavior first.
- If the battery repeatedly dies after replacement, perform a charging-system load test before replacing more parts.
- If voltage drops with headlights, blower motor, rear defroster, or AC load, charging-system weakness or cable voltage drop becomes more likely.
- If the battery warning light appears with P0562, confirm charging voltage before replacing the battery only.
- If no-start symptoms repeat after parking overnight, separate parasitic draw testing from charging failure diagnosis.
Diagnostic Insight
P0562 should be diagnosed as a low-voltage system fault, not just a battery or alternator code. Charging output, battery health, starter voltage drop, belt drive, grounds, terminals, and parasitic draw behavior all need to be separated before parts are replaced.
- Low voltage mainly at idle should move alternator output, belt slip, weak tensioner, idler condition, and pulley noise high on the test list.
- A new battery that keeps going dead points toward charging-system load testing, parasitic draw testing, or cable voltage-drop checks before another battery is installed.
- Voltage that falls when headlights, blower motor, rear defroster, or AC are switched on usually indicates charging weakness, cable resistance, corroded terminals, or engine ground voltage drop.
- A battery warning light with P0562 should be confirmed with charging-voltage and alternator-output data before the repair is treated as battery-only.
- Intermittent no-start or no-crank complaints need battery, starter, alternator, and ground voltage-drop testing during start attempts.
- Overnight no-start complaints need a separate parasitic-draw test so a drain is not confused with an alternator output failure.
Likely Repairs & Cost Guides
Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.
Price this when load or conductance testing proves the battery cannot hold charge after charging output, parasitic draw, and cable voltage drop are separated.
Use this path only after charging-system testing confirms low alternator output under electrical load, battery warning light behavior, or alternator control failure.
Start here when repeated dead batteries, dim lights, or P0562 could be caused by alternator output, weak battery, poor grounds, corroded terminals, or cable voltage drop.
Use this path when belt slip, pulley noise, weak tensioner action, or charging fluctuation at idle points to accessory-drive loss before major electrical parts are replaced.
Move here when the complaint is intermittent no-start or no-crank and voltage drop during start attempts must separate battery, starter, alternator, and ground faults.
Related OBD Codes
Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.
Next Steps
Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.