Charging and battery

P0562 — System Voltage Low

Severity: medium Drive with care, to a shop

What P0562 means

The engine control unit constantly monitors electrical system voltage. P0562 sets when it falls below the allowed threshold, typically around 11-12 V with the engine running. Normally the alternator holds about 13.5-14.5 V and keeps the battery charged, so a low reading points to a charging, supply or connection problem.

Symptoms

  • Dim headlights and dash lighting
  • Slow cranking at startup
  • Several warning lights on at once
  • Random communication (U-code) faults in other modules
  • Unstable idle
  • Glitchy electronics such as radio, windows or instrument cluster

Possible causes

  1. Weak, old or discharged battery
  2. Failing alternator, voltage regulator or rectifier
  3. Corroded or loose battery terminals
  4. Slipping or worn alternator drive belt
  5. Poor engine or body ground connection
  6. Damaged wiring or alternator output cable
  7. Parasitic drain from aftermarket accessories or a faulty module

How to diagnose

  1. Scan all codes and freeze-frame data, noting any U-codes
  2. Measure battery voltage with the engine off: a healthy, charged battery reads about 12.6 V
  3. Measure voltage with the engine running: expect 13.5-14.5 V
  4. Inspect terminals and clamps; clean and tighten if corroded
  5. Check the condition and tension of the alternator belt
  6. Perform voltage-drop tests on the positive cable and grounds under load
  7. Load-test the battery with a proper tester
  8. Measure parasitic draw with the car off and modules asleep

Common fixes

  • Charge or replace the battery
  • Clean and tighten terminals, replace damaged ends
  • Repair or replace the alternator or regulator
  • Replace the belt or tensioner
  • Repair grounds and damaged wiring
  • Find and eliminate the source of parasitic drain

Questions and answers

What does P0562 mean?

It means system voltage is lower than the ECU expects. The usual culprits are the battery, the alternator, or bad connections at the terminals and grounds.

Can I drive with P0562?

Only briefly and with caution. If the alternator isn't charging, the battery will run down and the car can stall, so check the charging system soon.

Can a weak battery cause other codes?

Yes. Voltage dips make modules behave erratically and log random U-codes and other faults, which often clear once the voltage problem is fixed.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.