OBD Guide

U3004

Accessory Power Relay

U3004 is an OBD-II diagnostic trouble code meaning: Accessory Power Relay. Common causes: faulty power relay, open or short circuit in the relay circuit. Estimated repair cost: $3–17.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$3–17 (est.)

Symptoms

  • Some electronic options of the car do not work
  • Periodic shutdown of additional equipment
  • Check Engine Light Is On
  • Problems starting some systems

Causes

  • Faulty power relay
  • Open or short circuit in the relay circuit
  • Problems with the control unit
  • Contact corrosion
  • Wiring harness damage

How to Fix

  1. Check the condition of the power relay
  2. Check the integrity of the relay circuit
  3. Inspect contacts for corrosion
  4. Check the voltage at the relay terminals
  5. If necessary, replace the relay

Related codes

Error U3004 by Vehicle Brand

FAQ

What does the U3004 code mean?

U3004 is an OBD-II diagnostic trouble code that indicates: Accessory Power Relay

What causes a U3004 error code?

The most common causes of U3004 include: Faulty power relay; Open or short circuit in the relay circuit; Problems with the control unit; Contact corrosion.

How do I fix a U3004 diagnostic trouble code?

To fix U3004: Check the condition of the power relay. Check the integrity of the relay circuit. Inspect contacts for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U3004?

Yes, but get it checked soon

How much does it cost to fix U3004?

The estimated repair cost for U3004 is $3–17. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat