Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0562 System Voltage Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The module measures its own supply voltage. CARB allows other monitors to be suspended below 11 V, and above a maker's threshold only if the voltage itself is diagnosed – that is what these codes record. GM's engine modules and Ford's PCM set them without warning lamp. P0562 means the voltage is below its threshold with the engine running, when the charging system should deliver: GM 9 V or less at 400 rpm or more in 400 of 500 samples (about 5 s), type C. Saab's 9-4X modules may switch off temporarily below about 9 V. Many other modules, such as GM's brake module, set P0562 themselves.

Likely causes

Alternator or regulator delivering too little
Battery faulty (shorted cell)
Corroded terminals, ground straps or alternator cable
High quiescent current or many consumers at idle

Symptoms

  • Battery or charge warning lamp
  • Starting problems, dim lights
  • Codes in several modules

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–600
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Test the battery
  2. Measure charging voltage with engine running
  3. Clean terminals and grounds

Parts involved

batteryalternatormodule power supplyengine control module

Related codes

P0560P0561P0563P0620P0622

References: gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com, roushcleantech.com.