P0562 - OBD II Trouble Code

Auto Systems and Repair

System Voltage Low

Our emissions expert has put together the following information about the P0562 fault code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the code.

OBD II Fault Code

  • OBD II P0562

Fault Code Definition

  • System Voltage Low
What does this mean?
The purpose of the Charging System is to maintain an ideal vehicle voltage level, which is usually 14.1 - 14.4 volts DC when the vehicle is idling with the lights off. When the code P0562 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is seeing a lower than requested vehicle voltage. The code will set when the voltage level goes below 10.0 volts for more than 60 seconds while the engine is running. 

Symptoms

  • Check Engine Light will illuminate
  • Battery Light may illuminate
  • Vehicle may not shift properly
  • Decrease in fuel economy
  • In unusual cases, there are no adverse conditions noticed by the driver
  • In some cases, there may be performance problems, such as dying when coming to a stop and/or misfire-like symptoms

Common Problems That Trigger the P052 Code

  • Defective Alternator
  • Defective Alernator wiring or connector(s)
  • Defective B+ battery cable from Alternator to battery
  • Poor Charging System ground(s)
  • Defective PCM wiring/connection to Alternator
  • Defective PCM
  • Defective Voltage Regulator
  • Large Parasitic battery drain
  • Defective Battery and/or cables

Common Misdiagnoses

  • Battery 
  • Starter

Polluting Gases Expelled

  • HCs (Hydrocarbons): Unburned droplets of raw fuel that smell, affect breathing, and contribute to smog
  • CO (Carbon Monoxide): Partially burned fuel that is an odorless and deadly poisonous gas
  • NOX (Oxides of Nitrogen): One of the two ingredients that, when exposed to sunlight, cause smog

P0562 Diagnostic Theory for Shops and Technicians

When diagnosing a P0562 code, it is important to record any other codes and the P0562 freeze frame data. Then one should duplicate the code setting conditions with a test drive.  Be sure to check voltage output from the Alternator B+ terminal and check the voltage drops from the Battery power and ground terminals for the charging system. I also like to pay close attention to the scan tool data, especially the charging system requested voltage vs the actual vehicle system voltage. I observe this while I change engine load, throttle position, RPM, and road speed because at times, P0562 can be difficult to detect.

 

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