OBD-II Code P0444 — What It Means & How to Fix It

What Does This Error Mean?

P0444 means the PCM detected an open circuit in the EVAP purge control valve circuit. The EVAP system captures fuel vapors from the gas tank and routes them into the engine to be burned. The purge valve controls when those vapors enter the engine. An open circuit means the PCM cannot control the valve — you may notice fuel odor and the check engine light.

Affected Models

All 1996+ gasoline vehicles with EVAP emission control systems
Common in GM trucks and SUVs with EVAP purge valve issues
Common in Ford and Lincoln vehicles with purge solenoid circuit faults
Common in Toyota and Honda vehicles with EVAP system problems
Common in Dodge and Chrysler vehicles with aging EVAP components

Common Causes

Open circuit in the wiring between the PCM and the EVAP purge control valve
Failed EVAP purge control valve solenoid with an open internal winding
Broken, corroded, or disconnected wiring harness connector at the purge valve
Blown fuse in the EVAP purge valve circuit
PCM output driver failure for the purge valve control signal (rare)

How to Fix It

Locate the EVAP purge control valve. It is usually a small cylindrical solenoid mounted near the engine intake manifold or on the firewall. Two vacuum/hose connections and a two-pin electrical connector identify it.

On many vehicles the purge valve is clearly labeled or identifiable by the hose running from the charcoal canister to the intake. Check your service manual for the exact location on your engine.
Inspect the purge valve connector and wiring. Check for a broken wire, loose connector pin, or obvious corrosion. Unplug the connector and reconnect it firmly. A loose connector is a simple fix that resolves P0444 without buying any parts.

The purge valve and its wiring can be damaged by engine heat or vibration over time. Inspect the entire length of the harness visible from the valve.
Test the purge valve solenoid resistance. With the valve connector unplugged, measure resistance across the two terminals. A healthy purge valve typically reads 14-30 ohms. An open circuit (infinite resistance) confirms the valve has failed internally.

Resistance specifications vary by vehicle. Check your service manual for the exact range if you want a precise comparison.
Check for power and ground at the valve connector. With the ignition on, use a test light or voltmeter to confirm voltage is present on the power supply wire. No voltage suggests a blown fuse or open circuit upstream of the valve.

Check all EVAP-related fuses in both the underhood and interior fuse boxes. A blown fuse is an inexpensive and easy fix.
Replace the EVAP purge control valve if it has an open circuit internally. Clear all stored fault codes and drive through several warm-up cycles. The EVAP monitor must complete — this may require a specific drive pattern including an idle and highway segment.

After an EVAP repair, it can take several drive cycles for the EVAP readiness monitor to complete and confirm the repair was successful.

When to Call a Professional

If the valve and its connector test fine but P0444 persists, the wiring harness between the valve and PCM needs tracing. A shop can quickly test circuit continuity with a wiring diagram. Diagnosis typically costs $80-$120. Purge valve replacement is usually $50-$150 including parts and labor.

Frequently Asked Questions

Is P0444 dangerous to drive with?

It is not an immediate safety emergency. The EVAP system manages fuel vapors, not engine combustion directly. However, a stuck-open purge valve can cause rough idle or stalling. A fuel odor near the vehicle is also a concern. Fix this code at your earliest convenience.

What is the EVAP purge valve supposed to do?

Your fuel tank constantly produces vapors as fuel evaporates. These vapors are stored in a charcoal canister. When conditions are right, the PCM opens the purge valve to draw those vapors into the engine and burn them. This prevents fuel vapors from escaping into the atmosphere. The purge valve controls when and how much vapor flows.

Can P0444 cause a rough idle?

Yes, if the purge valve is stuck open rather than having an open circuit. A stuck-open valve allows unmetered fuel vapor to enter the engine constantly. This creates a rich mixture at idle and can cause rough running or stalling. P0444 specifically is an open circuit code, meaning the PCM cannot control the valve at all.