Chevy Express: P0562 – System Voltage Low

P0562 is a common OBD-II trouble code.  It’s a general code, which means that it means the same thing for any vehicle, including the Chevy Express.  P0562 indicates that the system voltage is below 10 volts for a solid minute.  With the engine running, the system voltage should be 14.1-14.4 volts, and it’s typically caused by a bad alternator.  It’s very common to get the battery light with P0562.

P0562 Chevy Express


P0562 Quick Facts

  • P0562 is triggered whenever your Express’s voltage drops below 10 volts for over a minute straight.
  • Ideal voltage should be around 14 volts with the engine running.
  • There are usually no noticeable symptoms.
  • It is most commonly caused by a bad alternator.


P0562 Symptoms:  Chevy Express

Chevy Express P0562 Symptoms

If P0562 is the only code your Express has, there typically aren’t any noticeable symptoms.(other than the check engine/battery light).  Symptoms can and will appear if the battery voltage drops too far.

If you do experience symptoms, it’s due to battery drain.  it is very likely that your Express wouldn’t even turn back on if you tried.  The battery will have drained too much to engage the starter again.


Here are the most common P0562 Symptoms:

  • Check Engine Light– This is the most common symptom, and often the only symptom.
  • Low Battery Light/Warning–  You’ll more than likely get the battery light with this code.
  • Poor Fuel Economy–  This can occur when your Express’s engine and computer are not getting enough voltage.  It may not be able to correct the ignition timing or air/fuel mixture in real time anymore.  Or, the spark will be too weak.
  • Misfiring– Without enough voltage to fire the spark plugs properly, the motor will sputter and cough.  The check engine light may even begin to flash if the misfire is bad enough.
  • Problems Shifting– Today’s modern automatic transmissions are computer controlled.  Without enough voltage getting to them, they won’t be able to respond to the engine RPM and vehicle speed in a timely manner.
  • Won’t Start– A very common situation with P0562 is running the vehicle and everything is operating fine, and the check engine light comes on (battery light too, usually).  You get the vehicle home and when you go to drive it again it won’t start.  This strongly indicates a bad alternator.  


P0562 Causes + Diagnosis:  Chevy Express

Here are the most common causes of P0562:


1. Alternator

Express P0562 Diagnosis
A typical alternator

The alternator supplies voltage to the battery and to all of your Express’s electrical system while it is running.  If it goes bad, then it can cause P0562.  If it goes all the way bad that’s make diagnosing the code relatively easy.  The vehicle won’t start if it runs too long with a bad alternator.  How long it would take to drain the battery all the way is going to depend on the battery’s age and driving conditions.

It’s when the alternator begins to intermittently fail it can be tricky to diagnose.  Most auto parts stores will be able to test your alternator for free.  If you do end up needing a new alternator, they are somewhat affordable.  Make sure to change the serpentine belt while you are at it.

Chevy Express Alternator Diagnosis


2. Voltage Regulator

The voltage regulator ensures that a certain level of voltage passes to the charging system to keep it from overloading.  It can keep too much voltage from passing and throw P0562.


3. Battery Wiring

There’s a lot of wiring associated with your Express’s charging system.  You need to check for corrosion, fraying, and poor connections around the following wiring:

  • Battery Terminals– The battery terminals, if left alone long enough, will corrode on any vehicle.  When this happens it’s difficult for the charging system to function properly.
  • Alternator to Battery Wiring– Take a look at the wiring from the alternator to the battery.  Look to see if it has been damaged or frayed in any way.  Pay particular notice to any part that may be making contact with any other part of the engine.
  • Ground Wire– The ground wire that bolts to the negative battery terminal will bolt to the chassis or engine block.  Make sure that the connection is strong and corrosion free.
  • PCM Connection to Alternator– Check to see if the wiring going from the alternator straight to the PCM looks good.  It has a long distance to travel, and while well protected, can still get damaged.  Look for fraying where the wiring harness connects to the PCM.  This is the least likely wiring issue on this list, so only pursue it if everything else leads to a dead end.


4. Bad Battery

While a bad battery can throw P0562, it’s not nearly as likely as an alternator or wiring issue.  You should have it tested before replacing anyway.


5. Massive Battery Drain

If your vehicle has aftermarket equipment such as a very high watt stereo system, winch, or something else, it could be placing such a heavy load on the charging system that you’re getting P0562.  Remember, it needs to be at least a minute to throw the code.

There can also be a major power drain if something goes wrong as well.  This can happen if something shorts out and starts pulling way too much voltage.

Chevy Express Battery Drain Diagnosis


Conclusion:  P0562 Chevy Express

Tracking down P0562 can be tough.  It’s usually the alternator that is at fault.  If there is anything that you would like to add, please leave a comment below.  Good luck fixing your Express!