OBD Guide

P04AC

EVAP System Purge Control Valve B Circuit Low

P04AC is an OBD-II diagnostic trouble code meaning: EVAP System Purge Control Valve B Circuit Low. Common causes: open or short circuit in wiring harness, evap purge control valve malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine light comes on
  • Increased fuel consumption
  • Difficulty starting the engine
  • Unstable engine idling

Causes

  • Open or short circuit in wiring harness
  • EVAP purge control valve malfunction
  • Poor contact in connectors
  • Engine control unit (ECU) malfunction

How to Fix

  1. Check wiring harness and connectors for damage
  2. Check the resistance of the purge control valve
  3. Check power and ground on the valve
  4. Replace valve or repair wiring harness if necessary
  5. Clear the error and check if it comes back

Related codes

Error P04AC by Vehicle Brand

FAQ

What does the P04AC code mean?

P04AC is an OBD-II diagnostic trouble code that indicates: EVAP System Purge Control Valve B Circuit Low

What causes a P04AC error code?

The most common causes of P04AC include: Open or short circuit in wiring harness; EVAP purge control valve malfunction; Poor contact in connectors; Engine control unit (ECU) malfunction.

How do I fix a P04AC diagnostic trouble code?

To fix P04AC: Check wiring harness and connectors for damage. Check the resistance of the purge control valve. Check power and ground on the valve. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P04AC?

Limited driving only, diagnose soon

How much does it cost to fix P04AC?

The estimated repair cost for P04AC is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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