P0562
System Voltage LowP0562 is a generic OBD-II powertrain diagnostic trouble code: System Voltage Low. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0562 means
P0562 is an SAE generic code triggered when the power control module (PCM/ECM) measures battery voltage below a calibrated minimum — typically 11.0 V for 15 or more consecutive seconds, or immediately if voltage drops sharply below approximately 10 V. The PCM monitors system voltage at its own supply pins and sets this code when charging system output is insufficient to maintain normal operating voltage. It is classified as a Type C (emissions-unrelated) DTC on most platforms, so it does not illuminate the MIL on all manufacturers, though many do turn on the battery or charging system warning lamp instead.
The most common root cause is a failing battery that can no longer hold charge or accept a proper charge from the alternator. A worn alternator that is producing insufficient output voltage is the second most likely cause — alternator output should be 13.7–14.7 V at idle with the vehicle fully warmed up. Belt slippage on the alternator pulley from a worn or glazed serpentine belt is frequently overlooked and should be checked early in diagnosis, as it is an inexpensive fix compared to alternator replacement. Loose or corroded battery terminal connections create resistance in the charging circuit, causing a voltage drop between the alternator and the PCM supply that can trigger this code even with a healthy battery and alternator.
If left unresolved, chronic low-voltage operation can cause erratic behaviour across multiple control modules, data corruption in adaptive memory, and transmission shift anomalies. On diesel vehicles, glow plug control may be compromised, leading to hard cold starts and potentially triggering additional DTCs. Full charging system testing with a dedicated tester is the most efficient diagnostic approach.
Common causes
Most-frequently reported root causes when P0562 is logged.
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1
Failing or discharged battery unable to sustain voltage under load
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2
Worn or failed alternator producing insufficient charging voltage
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3
Slipping, cracked, or glazed alternator drive belt
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4
Loose, corroded, or poor-contact battery terminal connections
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5
High-resistance connections in the main charging cable (alternator B+ to battery)
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6
Excessive parasitic current draw discharging the battery faster than the alternator can recharge
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7
Defective voltage regulator (internal to alternator on most modern units)
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8
PCM power supply wiring fault causing false low-voltage reading at the PCM
Symptoms drivers notice
How to diagnose P0562
A typical diagnostic flow when this code is present.
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1
Measure battery open-circuit voltage with a multimeter — a fully charged 12 V battery should read 12.4–12.7 V; below 12.0 V indicates a discharged or failing battery
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2
Start the engine and measure alternator output voltage at the battery terminals — acceptable range is 13.7–14.7 V at idle; below 13.5 V indicates insufficient alternator output
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3
Visually inspect and manually flex the serpentine belt for cracks, glazing, or missing ribs; check belt tension against specification
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4
Check battery terminals and main charge cables for corrosion, looseness, or heat damage; clean or replace as needed
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5
Perform a battery load test with a dedicated tester to evaluate cold cranking amp capacity against battery specification
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6
Check for excessive parasitic drain with an ammeter in series on the negative battery cable (typical acceptable drain: under 50 mA with all accessories off and modules in sleep mode)
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7
If all above pass, perform a voltage drop test on the charging circuit: measure voltage drop between alternator B+ output and battery positive terminal while charging — more than 0.5 V drop indicates a resistance fault in the main cable or fusible link
Vehicles where we've handled P0562
Platforms in our catalogue with confirmed P0562 coverage.
Related powertrain codes
Frequently asked questions
Will P0562 clear itself after charging the battery?
If the code was set by a deeply discharged battery that has now been properly recharged and load-tested as healthy, it may not return. However, if the battery is failing or the alternator is weak, the code will recur during normal driving. Always identify and fix the root cause rather than simply clearing and hoping.
Can P0562 cause other fault codes to appear?
Yes. Low system voltage causes multiple control modules to log undervoltage DTCs simultaneously. You may see codes across engine, transmission, ABS, airbag, and body modules. After repairing the charging system fault, clear all codes and perform a full drive cycle — most secondary codes will not return once voltage is stable.
How do I know if it is the battery or the alternator?
Charge the battery fully, then measure alternator output voltage at idle (13.7–14.7 V expected). If output is good, load-test the battery — a battery that fails a load test despite being fully charged needs replacement. If alternator output is below 13.5 V with a good battery, test the belt and alternator output circuit before condemning the alternator itself.
Is it safe to drive with P0562 active?
Driving is possible for short distances to reach a workshop, but the risk of the battery discharging completely and leaving the vehicle stranded is real. On vehicles where P0562 suppresses glow plug operation or causes transmission shift faults, driving conditions may deteriorate quickly. Diagnose and repair as soon as possible.
Disabling P0562 in software
RaceTune can permanently disable P0562 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
ECUs with a P0562 disable in our catalogue
Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.
- Bosch EDC17C60 verified 2 software versions
- Bosch EDC17CP57 verified 2 software versions
- Bosch EDC17C66 verified 1 software version
- Bosch MD1CP004 verified 1 software version
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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