# P0562: System Voltage Low **Verdict:** Drive to a shop this week Computer and outputs - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996. - **Typical cost:** $30-$900 - **Urgency:** This week - **Most likely:** Weak battery or failing alternator - **DIY?:** Steps 1-2 ## Quick answer P0562 means the engine computer has seen the car's electrical system voltage drop below what it needs. The usual causes are a weak battery, a failing alternator, or a loose or corroded battery cable or ground. If the charging system is failing, the car can eventually die while driving. ## What does P0562 mean? Your car's electrical system runs on about 12.6 volts from the battery with the engine off, and roughly 13.5 to 14.7 volts with the engine running and the alternator charging. The engine computer constantly measures the voltage reaching it, because sensors, fuel injectors, ignition coils, and transmission solenoids all need steady voltage to work as designed. P0562 sets when that measured voltage stays below a minimum threshold for a set amount of time, usually with the engine running. The exact threshold, timing, and whether the check engine light turns on all vary by maker, and on some cars the code is stored without lighting the dash at all. Because the computer measures voltage at its own power feed, a weak battery, a tired alternator, a slipping belt, or a poor cable or ground connection anywhere in between can cause it. ## What are the symptoms of P0562? - Battery or charging warning light on - Dim or flickering headlights and dash lights - Slow cranking or no-start - Odd electrical behavior, such as gauges or radio cutting out - Check engine light on ## What causes P0562? Ranked from most to least likely. Check them in this order: the cheap, common causes first. 1. **Weak or failing battery** (most common). Batteries lose capacity with age, often after 3 to 5 years, and faster in hot climates where heat speeds internal wear. A weak battery may show normal voltage at rest but sag badly under load, such as during cranking. A load test at a shop or parts store shows whether it can still hold and deliver a charge. 2. **Failing alternator** (common). The alternator recharges the battery and powers the car while the engine runs. Worn brushes, a failed voltage regulator, or bad internal diodes reduce its output, often gradually. A running voltage below about 13 volts with the lights and blower on points to the charging system, and the battery warning light often comes on too. 3. **Loose or corroded battery cables or grounds** (common). Corrosion on the battery posts, loose clamps, or a corroded engine-to-body ground strap add resistance, which drops voltage when heavy loads like the starter, blower, or rear defroster are on. It is common on older cars and in humid or road-salt climates. White or green crust and cables that feel warm are clues. 4. **Worn or slipping serpentine belt** (less common). The serpentine belt drives the alternator, and a worn, glazed, oil-soaked, or loose belt can slip, so the alternator spins too slowly to charge fully. Slipping often shows up as a squeal on cold or wet mornings, at startup, or when the AC and other loads switch on. A weak automatic tensioner causes the same problem. 5. **Wiring fault at the engine computer** (rare). The engine computer measures voltage at its own power and ground pins. A corroded connector, a loose fuse, a bad relay, or a poor ground can make voltage look low to the computer even when the battery and alternator test fine. This is rare and is traced with a voltage drop test after the charging system passes. ## How do you diagnose P0562? 1. Measure battery voltage with the engine off (about 12.6 volts is fully charged) and running (about 13.5 to 14.7 volts is normal). 2. Load test the battery to check its health. 3. Clean and tighten battery terminals and check the main engine and body grounds. 4. Inspect the serpentine belt and test alternator output under load. ## How do you fix P0562, and what does it cost? | Fix | Typical cost | What it involves | | --- | --- | --- | | Clean or replace battery terminals and cables | $30-$200 | A cheap fix for corrosion or loose connections. | | Replace battery | $180-$400 | AGM batteries for start-stop cars cost more. | | Replace alternator | $450-$900 | Labor varies with how hard the alternator is to reach. | Full price breakdowns: [car battery replacement cost](/cost/car-battery-replacement), [alternator replacement cost](/cost/alternator-replacement), [serpentine belt replacement cost](/cost/serpentine-belt-replacement). ## Is it safe to drive with P0562? > **Drive to a shop this week.** Drive only if the voltage is close to normal and you can get to a shop soon. If the battery light is on and lights are dimming, the car may stall soon, so do not start a long trip. ## Will P0562 fail an emissions test? P0562 is not an emissions fault itself, but if it turns on the check engine light, the car fails an OBD-II test in most states. The bigger trap is the repair: replacing or disconnecting the battery erases the readiness monitors on many cars. Drive normally for several days after any battery or alternator job before testing. ## After the repair: clearing P0562 After fixing the battery, alternator, belt, or connections, clear the code and recheck voltage: about 12.6 volts with the engine off, and 13.5 to 14.7 volts running with the lights and blower on. Some cars, often those with start-stop, need a new battery registered with a scan tool. Steady voltage and no returning code mean success. ## How to prevent P0562 - Have the battery load tested every year once it is about three years old, ideally before winter. - Clean battery terminals and keep the clamps tight, since white or green corrosion adds resistance. - Replace a cracked, glazed, or squealing serpentine belt before it starts slipping or breaks. - Avoid long periods with accessories on and the engine off, which drain and weaken the battery. - Use a battery maintainer if the car sits unused for several weeks at a time. ## Codes often seen with P0562 - [P0700](/codes/p0700): Transmission Control System (MIL Request) - [P0335](/codes/p0335): Crankshaft Position Sensor "A" Circuit ## Frequently asked questions ### Can I drive with a P0562 code? Only for a short distance if the car seems normal. Low system voltage can lead to stalling, odd shifting, or a no-start, because many systems need steady voltage. If the battery light is on or the lights are dimming, head to a shop and avoid shutting the car off far from help. ### Can a bad battery cause P0562? Yes, a weak battery is the most common cause of P0562, especially one more than three to five years old. Many auto parts stores and repair shops will test the battery and alternator for free or for a small fee. A load test tells you far more than a simple voltage reading. ### How do I know if it is the battery or the alternator? Check voltage with the engine running, where a healthy charging system shows about 13.5 to 14.7 volts. If running voltage is low, suspect the alternator or belt. If it is normal but the car cranks slowly or the battery fails a load test, suspect the battery. ### How much does it cost to fix P0562? Most P0562 repairs cost $30 to $900. Cleaning or replacing battery terminals and cables runs about $30 to $200, a new battery about $180 to $400, and a replacement alternator about $450 to $900. AGM batteries for start-stop cars and hard-to-reach alternators sit at the high end. ### Can I fix P0562 myself? Often, yes. Cleaning corroded terminals and replacing a conventional battery are common DIY jobs with basic tools, gloves, and eye protection. Some newer cars need the new battery registered with a scan tool, and alternator replacement ranges from easy to hard depending on access. Test before buying parts. ### Can P0562 cause transmission problems? Yes, on some cars. Transmission solenoids and the transmission computer need steady voltage, so low voltage can cause harsh shifts, a stuck gear, or extra codes such as P0700. Fix the voltage problem first, then recheck, because those transmission codes often stop returning once voltage is normal. ### Why does P0562 come and go? An intermittent P0562 often comes from a loose or corroded connection that loses contact over bumps, a belt that slips only when cold or wet, or an alternator that weakens as it heats up. Note when the code appears, such as at idle with the AC on, to help the shop find it. ### Will a new battery clear P0562? If the battery was the cause, the code usually stops returning, and disconnecting the battery erases stored codes on many cars. Otherwise, clear it with a scan tool. If the alternator, belt, or a ground was the real problem, the new battery will run down and P0562 will come back. ### Will P0562 fail an emissions test? If the check engine light is on with P0562 stored, most OBD-II inspection states will fail the car. Replacing or disconnecting the battery during the repair also resets the readiness monitors on many vehicles. Plan on several days of normal driving after the repair before you go in for the test. ### What voltage is too low for a car? With the engine running, voltage below about 13 volts usually means the charging system is not keeping up. With the engine off, a rested battery below about 12.4 volts is partly discharged. The exact voltage that sets P0562 varies by maker, but it is well below the normal running range. ## Sources - [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/) ## Other computer and outputs codes - [P0500 Vehicle Speed Sensor "A"](https://diagxcar.com/codes/p0500) - [P0505 Idle Air Control System](https://diagxcar.com/codes/p0505) - [P0506 Idle Air Control System RPM Lower Than Expected](https://diagxcar.com/codes/p0506) - [P0507 Idle Air Control System RPM Higher Than Expected](https://diagxcar.com/codes/p0507) - [P0520 Engine Oil Pressure Sensor/Switch "A" Circuit](https://diagxcar.com/codes/p0520) - [P0521 Engine Oil Pressure Sensor/Switch "A" Circuit Range/Performance](https://diagxcar.com/codes/p0521) - [P0522 Engine Oil Pressure Sensor/Switch "A" Circuit Low](https://diagxcar.com/codes/p0522) - [P0523 Engine Oil Pressure Sensor/Switch "A" Circuit High](https://diagxcar.com/codes/p0523) - [P0524 Engine Oil Pressure Too Low](https://diagxcar.com/codes/p0524) - [P0571 Brake Switch "A" Circuit](https://diagxcar.com/codes/p0571) - [P0601 Internal Control Module Memory Check Sum Error](https://diagxcar.com/codes/p0601) - [P0606 Control Module Processor](https://diagxcar.com/codes/p0606) - [P0740 Torque Converter Clutch Solenoid Circuit/Open](https://diagxcar.com/codes/p0740) - [P0750 Shift Solenoid "A"](https://diagxcar.com/codes/p0750) ## Symptoms - [Why won't my car start?](https://diagxcar.com/symptoms/car-wont-start) - [Why does my car click but not start?](https://diagxcar.com/symptoms/car-clicks-but-wont-start) - [Why does my car stall while driving?](https://diagxcar.com/symptoms/car-stalls-while-driving) - [Why does my car battery keep dying?](https://diagxcar.com/symptoms/car-battery-keeps-dying) - [Why are my headlights flickering?](https://diagxcar.com/symptoms/headlights-flickering) - [Why does my car squeal when I start it?](https://diagxcar.com/symptoms/squealing-noise-when-starting) - [Why does my car whine when I accelerate?](https://diagxcar.com/symptoms/whining-noise-when-accelerating) ## Repair costs - [Car battery replacement cost](https://diagxcar.com/cost/car-battery-replacement): $150-$450 - [Alternator replacement cost](https://diagxcar.com/cost/alternator-replacement): $450-$1,100 - [Serpentine belt replacement cost](https://diagxcar.com/cost/serpentine-belt-replacement): $100-$250 ## Warning lights linked to this - [Battery (charging system) warning light](https://diagxcar.com/warning-lights/battery) - [Power steering warning light](https://diagxcar.com/warning-lights/power-steering) --- Source page: https://diagxcar.com/codes/p0562 Updated: 2026-11-03 General information, not a substitute for a qualified mechanic.