Chevrolet Monte-carlo · Diagnostic Trouble Code
P0562 — System Voltage Low
What it means, how urgent it is, the most likely causes, and the exact order to diagnose it — with the repair guides that fix it.
What P0562 means
Your Chevrolet Monte Carlo's electronics expect roughly 12.6 volts with the engine off and 13.7–14.7 volts with it running. The PCM watches system voltage continuously; when it stays below about 10–11 volts for a set time, P0562 sets and the check engine light comes on.
Low voltage is usually a symptom, not the disease: either the battery cannot hold charge, or the alternator cannot make enough of it. Electrical gremlins that seem random — flickering lights, weak cranking, modules acting strangely — often trace back to exactly this.
⚠️ How urgent is it?
Check it the same day if possible: most auto parts stores test batteries and alternators free. If voltage is dropping while driving (lights dimming, gauges flickering), head straight somewhere safe — you are on borrowed time.
Most likely causes
- A weak or failing battery that can no longer hold a charge — the most common cause, especially on batteries over 3–4 years old.
- A failing alternator not producing enough output to maintain system voltage.
- Corroded, loose, or damaged battery terminals and cables creating resistance.
- A parasitic drain slowly depleting the battery overnight.
- Bad engine or chassis ground straps.
- A faulty voltage regulator (internal to most modern alternators).
How to diagnose it — in order
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1
Measure battery voltage with the engine off. A healthy battery reads about 12.6V; 12.0V or less means it is significantly discharged.
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2
Measure voltage with the engine running. You should see roughly 13.7–14.7V. Below 13.5V with loads on points to the alternator.
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3
Load-test the battery. Voltage alone can lie — a proper load test reveals a battery that collapses under demand.
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4
Inspect and clean the battery terminals and cable ends. Corrosion here causes voltage drop that mimics a bad battery or alternator.
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5
Check alternator output under load: headlights, blower, and defroster on, engine at 2,000 RPM — voltage should hold in the normal charging range.
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6
If the battery and alternator test good but voltage keeps dropping overnight, test for parasitic drain with an ammeter (normal draw is typically under 50 milliamps).
Reading the code is step zero
A basic OBD2 scanner plugs into the port under your dash and tells you exactly which codes are stored — plus freeze-frame data showing what the engine was doing when the code set.
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Repair guides that fix P0562
General diagnostic information, not a factory service procedure. If you're unsure, have a qualified technician confirm the diagnosis before buying parts.