P0562
- Powertrain
- Generic (SAE)
Get it looked at now
Nothing is being destroyed, but a charging system that is failing will strand the vehicle, usually with no warning beyond this code. If the engine quits in traffic, steering effort rises sharply, and on a vacuum-boosted brake system the booster holds reserve for only about one or two pedal applications, after which the brakes still stop the car but demand far more pedal force. On vehicles with electric power steering or electrically supported braking, those systems depend directly on the supply this code says is failing. That is a safety concern, not just a drivability one. It is not engine-damaging, which is why it is not critical, but it should not wait.
- Safe to drive
- Have the battery and charging system tested today, and avoid night driving, heavy accessory loads, and long trips until it is. If the battery or charge warning light is on, if the headlights dim, or if the vehicle is slow to crank, drive straight to a shop. The vehicle can stall and lose power steering assist with little warning, and the warning light is often absent on a module-controlled charging fault, so do not treat a dark dash as an all-clear.
System Voltage Low
The computer measured its own supply voltage below the minimum it will tolerate while the engine was running. That points at the battery, the charging system, or the cables and grounds between them.
The PCM monitors system voltage on its own power feed or a dedicated battery-sense circuit. When that voltage stays below the calibrated lower limit, commonly in the region of 10 volts, for longer than the confirmation time with the engine running, P0562 sets. The strategy normally excludes cranking, when a dip is expected. Modules are sensitive to under-voltage because injector, coil, and solenoid drive all depend on supply, so low voltage also produces a scatter of unrelated-looking secondary codes.
How the car detected itThe module samples supply voltage continuously with the engine running. A sustained reading below threshold, usually above idle speed where the alternator should be producing full output, sets the code. A weak battery can also produce it briefly at start-up if the voltage recovery is slow. Because the measurement is taken at the module, a corroded feed or a poor ground between the battery and the module can set this code even when the battery terminals themselves measure fine.
A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.
- Safe to drive
- Have the battery and charging system tested today, and avoid night driving, heavy accessory loads, and long trips until it is. If the battery or charge warning light is on, if the headlights dim, or if the vehicle is slow to crank, drive straight to a shop. The vehicle can stall and lose power steering assist with little warning, and the warning light is often absent on a module-controlled charging fault, so do not treat a dark dash as an all-clear.
- Urgency
- Get it looked at now
- Will it pass emissions
- Not affected
- If ignored
- The battery drains until the vehicle will not start, often within days. Before that you may see erratic transmission shifting, warning lights across the dash, and modules setting communication faults, because every module on the vehicle misbehaves when the supply sags. A sustained deep discharge also permanently damages the battery, so an ignored charging fault typically costs a battery as well as the original repair.
- Check engine light
- Solid
These are the causes this code can have. For the order to work through them in, see what to check first.
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | Battery aged or weak | Very common | — |
| 2 | Alternator undercharging | Common | — |
| 3 | Corroded battery terminals or ground strap | Common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
In order. Each of these is cheaper or faster than what follows it, and each one can make the rest unnecessary.
Battery terminals, cable ends, and ground straps
Free to inspect and a very common cause. Corrosion under the terminal clamp, a loose clamp, or a corroded engine-to-body ground strap all produce low voltage at the module with a perfectly good battery and alternator.
The drive belt and tensioner
A glazed, slipping, or missing belt stops the alternator from charging. A quick look and a listen for squeal at load answers this in a minute.
Charging voltage at the battery with the engine running
One meter reading immediately splits the diagnosis into charging fault or battery and cable fault, and it costs nothing.
Battery age and a load or conductance test
A battery past roughly four to five years is a leading cause. Testing it properly is quick and free at most parts stores, and a weak battery makes every other reading harder to trust.
The scan tool voltage reading against a meter at the battery
If the scan tool shows notably less than the meter, the loss is in the feed or ground to the module, not in the charging system. This one comparison redirects the whole diagnosis.
Record all codes and freeze frame
Tools OBD-II scan tool
Note the voltage value in freeze frame and the engine speed and run time when the code set. Low voltage sets sympathetic codes in other modules, so identify which codes are causes and which are consequences before chasing any of them.
ExpectedP0562 with a recorded low voltage value, plus possible secondary codes that clear once the supply is fixed
Inspect and clean all battery connections and grounds
Tools Wrenches, wire brush, terminal cleaner
Remove the terminal clamps and inspect the mating surfaces, not just the outside. Check the main engine-to-body and body-to-battery ground straps for corrosion and loose fasteners. Check for aftermarket accessory wiring spliced into the supply.
ExpectedBright, tight connections on both posts and every ground strap
Measure resting battery voltage and load test the battery
Tools Digital multimeter, battery load or conductance tester
With the vehicle off for a few hours, a healthy twelve-volt lead-acid battery reads about 12.6 volts, and below about 12.4 indicates partial discharge. AGM batteries read slightly higher. Follow with a proper load or conductance test rather than judging by voltage alone.
ExpectedResting voltage near 12.6 volts and a load test result that passes the battery's rated capacity
Measure charging voltage at the battery with the engine running
Tools Digital multimeter, scan tool with charging system data
Most conventional systems charge somewhere in the region of 13.5 to 14.7 volts. Many current vehicles use a regulated charging strategy where the module deliberately commands lower voltage at times, so compare the measured value against the module's commanded or desired charging voltage rather than assuming a fixed target.
ExpectedMeasured voltage matching what the module is commanding, and rising under electrical load when demanded
Perform voltage drop tests on the charging and ground paths
Tools Digital multimeter
With the engine running and a heavy electrical load applied, measure the drop from the alternator output stud to the battery positive post, and from the alternator case to the battery negative post. A widely used general limit is under about 0.2 to 0.3 volts on each path. More than that means resistance in a cable, fusible link, or connection.
ExpectedLow drop on both the positive and the ground path under load
Compare module-measured voltage to battery voltage
Tools Scan tool, digital multimeter
With the engine running, read the system voltage PID on the scan tool and simultaneously measure at the battery posts. A meaningful gap means the module's own feed or ground is the problem, not the alternator, and sends you into that circuit instead.
ExpectedScan tool voltage closely tracking the measured battery voltage
Test the charging system control circuits before condemning the alternator
Tools Scan tool, wiring diagram, oscilloscope where available
Many alternators are regulated by the engine module over a communication or pulse-width control line. Confirm the module is actually commanding output before replacing the alternator. Where the vehicle has a battery current sensor, verify it is reading plausibly, because a failed sensor can cause deliberate undercharging.
ExpectedThe module commanding a normal charging target and the alternator responding to it
Check for a parasitic draw if the battery goes flat overnight
Tools Digital multimeter or clamp meter, service information
If the vehicle sits and dies but charges normally when running, measure key-off current draw after the modules have gone to sleep, which can take up to an hour on some vehicles. Pull fuses systematically to isolate the circuit.
ExpectedKey-off draw within the manufacturer's stated limit after full sleep
| Repair | Only after you confirm | Typical cost | Who |
|---|---|---|---|
| Clean or replace corroded battery terminals, cable ends, or ground straps | Excessive voltage drop measured on the positive or ground path, or visible corrosion under the clamp | $40–$220 | DIY |
| Replace the battery | A failed load or conductance test, or a battery that will not hold resting voltage after a full charge | $180–$500 | DIY |
| Replace the alternator | Charging voltage below the module's commanded target with good cables, good grounds, a good belt, and the control circuit proven to be commanding output | $450–$1,300 | Hard |
| Replace the drive belt, tensioner, or pulley | A glazed, cracked, or slipping belt, or a tensioner that will not hold tension, with charging recovering once corrected | $150–$500 | DIY |
| Repair a burnt fusible link, main charging cable, or corroded junction | High voltage drop isolated to that specific section of the charging path under load | $120–$550 | DIY |
| Repair the module power feed or ground circuit | Scan tool system voltage reading meaningfully lower than the voltage measured at the battery posts | $120–$500 | DIY |
| Locate and correct a parasitic draw | Key-off current above the manufacturer's limit after the vehicle has gone to sleep, isolated to a specific circuit | $150–$600 | DIY |
| Replace a failed battery current or temperature sensor causing deliberate undercharging | Implausible sensor data on the scan tool with the module commanding a low charge target as a result | $150–$450 | DIY |
US independent shop ranges, parts and labor. Battery price varies with group size and chemistry, with AGM at the top of the range. Alternator cost swings on accessibility; some are behind the engine or require removing other accessories. Some vehicles also require a battery registration or reset procedure after replacement.
- Replacing the alternator first. A corroded ground strap, a bad cable end, or a burnt fusible link produces identical symptoms for a fraction of the cost.
- Fitting a new battery without testing the charging system, so the new battery is flattened by the same untouched fault.
- Judging a modern charging system by a fixed target voltage. Regulated systems intentionally vary output, so the meter reading has to be compared against what the module is commanding.
- Chasing the secondary codes that low voltage caused in other modules instead of fixing the supply and re-checking.
- Ignoring aftermarket wiring, amplifiers, and accessory installs, which are a frequent source of both parasitic draw and voltage drop.
- Testing charging voltage with no electrical load applied, which can hide a marginal alternator.
- Treating an unlit battery or charge warning lamp as evidence the charging system is fine. On a module-controlled charging fault the lamp is frequently never commanded on.
- 12-Volt Battery
- Alternator
- Alternator Belt
- Battery Cables
- Definition
- Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
- Diagnostic guidance
- Written and reviewed in-house. See our editorial policy.
- Review status
- Reviewed
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