OBD Guide
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P1594

Charging System Voltage Too High

P1594 is an OBD-II diagnostic trouble code meaning: Charging System Voltage Too High. Common causes: faulty voltage regulator, problems with the generator. Estimated repair cost: $33–167.

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

P0562P0563P0620

Error P1594 by Vehicle Brand

BMWDodgeJeepPlymouthPontiacSubaru

FAQ

What does the P1594 code mean?

P1594 is an OBD-II diagnostic trouble code that indicates: Charging System Voltage Too High

What causes a P1594 error code?

The most common causes of P1594 include: Faulty voltage regulator; Problems with the generator; Short circuit in charging circuit; Damaged wiring or poor contacts.

How do I fix a P1594 diagnostic trouble code?

To fix P1594: Check the battery voltage with the engine running. Inspect the wiring and connections of the generator. Check voltage regulator. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1594?

Do not drive — repair immediately

How much does it cost to fix P1594?

The estimated repair cost for P1594 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat