OBD Guide

P1594

Charging System Voltage Too High

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–167 (est.)

Symptoms

  • Check engine light is on
  • Bulbs and fuses burn out
  • Unstable operation of electrical equipment
  • Burning smell from battery or generator
  • Headlights are too bright

Causes

  • Faulty voltage regulator
  • Problems with the generator
  • Short circuit in charging circuit
  • Damaged wiring or poor contacts
  • Faulty ECU

How to Fix

  1. Check the battery voltage with the engine running
  2. Inspect the wiring and connections of the generator
  3. Check voltage regulator
  4. Test the generator on the stand
  5. If necessary, replace the generator or voltage regulator

Related codes

Error P1594 by Vehicle Brand