P0562moderate severityGenerally driveableP0562 Code: System Voltage Low
Written in plain English and reviewed by the eli5cars editorial team · Last reviewed June 2026
What it means in plain English
Every module in your car — the ECM, transmission control, ABS, body control — needs stable electrical voltage to function correctly, usually right around 13.5-14.8 volts while the engine is running (charging system) or 12.4-12.6 volts with the engine off (battery resting voltage). P0562 means the ECM is seeing system voltage that's lower than that expected range. This almost always points to a charging system problem (the alternator isn't replenishing the battery fast enough) or a battery/connection issue, not a problem with the ECM itself.
Most likely causes — ranked
#1 Failing or undercharging alternator
most likelyFix: If the alternator can't keep up with electrical demand, system voltage drops below spec even while driving. Test with a multimeter across the battery terminals with the engine running: a healthy system reads 13.5-14.8 volts. A reading at or below battery resting voltage (around 12.6V) with the engine running means the alternator isn't charging adequately. AutoZone and O'Reilly will test the alternator for free. Replace if it fails the test.
#2 Weak, old, or failing battery unable to hold a stable charge
likelyFix: A battery near end-of-life can't maintain voltage under load even if the alternator is working fine, which drags overall system voltage down and can trigger P0562. Have the battery load-tested (free at most parts stores) — a battery that's more than 3-5 years old and fails a load test should be replaced. Also check the battery date code before assuming the alternator is at fault.
#3 Corroded, loose, or high-resistance battery cable connections
likelyFix: Corrosion at the battery terminals or a loose ground strap creates resistance in the charging circuit, dropping voltage before it ever reaches the ECM — even with a perfectly good alternator and battery. Inspect both battery terminals and the engine-to-body/frame ground straps for corrosion (white/blue-green crust) or looseness. Clean with a wire brush and battery terminal cleaner, or replace corroded cables. This is one of the cheapest and most overlooked fixes for this code.
#4 Failing or slipping serpentine belt reducing alternator drive speed
possibleFix: The alternator is spun by the serpentine belt. A glazed, worn, or slipping belt (or a weak automatic tensioner) can cause the alternator to underperform without the alternator itself being faulty. Inspect the belt for glazing, cracks, or visible slip marks, and check tensioner spring tension. Replacing a worn belt is far cheaper than an unnecessary alternator swap.
Check engine light on? Get a free code scan
If your check engine light is on, most auto-parts stores (AutoZone, O'Reilly, Advance) will read the code for FREE — no purchase required, just walk in. Bring the code back here and look it up at eli5cars.com/obd2 for the plain-English explanation.
Note: a scan only helps when there's an active fault code. For purely mechanical symptoms (noises, vibrations, leaks), a scan may show nothing — the suspects listed above are your starting point.
Want to read the codes yourself?
First, the free option: AutoZone, O’Reilly, and Advance Auto Parts read your codes for free — no purchase needed. That’s the cheapest way to get the code to look up here. If you’d rather have your own so you can check anytime (and clear a code after a fix), the Veepeak OBDCheck BLE is an inexpensive, reliable plug-in reader that pairs with a free phone app and works on any car sold since 1996.
See the Veepeak OBD2 scanner on AmazonAffiliate link — we may earn a commission at no extra cost to you. Details.
Heads up: some links below are affiliate links (including Amazon Associates) — if you buy through them we may earn a small commission at no extra cost to you. Details: /disclosure.
Frequently asked questions
Is it safe to drive with a P0562 code?
Short-term, usually yes — but treat it as urgent, not routine. Low system voltage means your charging system may be failing, and if the battery drains fully while driving you can lose power steering, power brakes assist, and the engine can stall unexpectedly, sometimes at highway speed. Get it diagnosed within a day or two, not weeks.
Will P0562 clear itself?
No. Low system voltage is caused by a real electrical fault in the charging system, battery, or connections. The code may stop being 'active' if voltage briefly recovers, but it will return until the actual cause — alternator, battery, or corroded connection — is fixed.
Could P0562 leave me stranded?
Yes, and this is what makes it different from a routine emissions code. If the charging system truly isn't keeping the battery charged, the vehicle can lose electrical power and stall while driving, often with little warning. If you notice dimming lights, flickering dash gauges, or accessories acting up alongside this code, get to a shop the same day.
Is P0562 the same as a low battery warning light?
They're related but not identical. A battery/charging warning light is a driver-facing alert for the same underlying problem — low system voltage. P0562 is the specific OBD2 diagnostic code the ECM stores when it detects that condition. If both appear together, it reinforces that this is a real charging or battery issue, not a sensor glitch.