P0444: EVAP System Purge Control Valve A Circuit Open
What Does P0444 Mean?
P0444 is a diagnostic trouble code indicating: EVAP System Purge Control Valve A Circuit Open. This code relates to the emission controls system. It has been reported in NHTSA complaints across 2 different vehicle models.
The emission control system reduces harmful exhaust pollutants through several subsystems: EGR (Exhaust Gas Recirculation) recirculates a portion of exhaust back into the intake to lower combustion temperatures and reduce NOx. The secondary air injection system pumps fresh air into the exhaust during cold starts to help the catalytic converter light off faster. The catalytic converter converts CO, HC, and NOx into CO2, H2O, and N2. The EVAP system captures fuel vapors from the tank and purges them into the engine for combustion. When any of these systems malfunction, the vehicle will fail emissions testing and the ECM will set a DTC.
Symptoms of P0444
- ⚠️ Check engine light on
- ⚠️ Failed emissions/smog test
- ⚠️ Possible rough idle or stalling (EGR stuck open)
- ⚠️ Fuel smell (EVAP leak)
- ⚠️ Reduced performance in some cases
- ⚠️ Increased tailpipe emissions
Common Causes
- 🔍 Carbon buildup causing EGR valve to stick
- 🔍 EVAP system leak (gas cap, hose, canister, purge valve)
- 🔍 Catalytic converter below efficiency threshold (aging)
- 🔍 Secondary air pump failure or check valve stuck
- 🔍 Wiring or vacuum line issue in emission control circuit
P0444 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"Problem: Reoccurring check engine light and ODB2 Code's P0443 & P0444 Repairs made: MAF Sensor Purge Control Valve Reset Computer Air filter Cap less Gas Fill, W0133-2022154 Related Safety recalls: 18S32, 19V515000, 18V735 or 18V735000 I believe the Problem occurs due to an recall that was not "
— Ford Focus owner, 02/01/2022
"ENGINE ON OUR 2005 HYUNDAI TUCSON TURNED OFF IN THE MIDDLE OF A BUSY HIGHWAY GOING APPROXIMATELY 40 MPH. MANAGED TO TURN/ROLL OFF THE ROAD WITHOUT POWER OR POWER STEERING. HAD TO RESTART CAR SEVERAL TIMES AS IT WOULD STALL OUT ON ACCELERATION OR WHEN SLOWING TO TURN. PAID DEALERSHIP $209 TO "FIX" TH"
— Hyundai Tucson owner, 08/25/2012
Source: NHTSA Complaints Database
Most Reported Vehicles for P0444
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | FORD FOCUS | |
| 2 | HYUNDAI TUCSON |
Diagnostic Tips
- For EVAP codes: start with the gas cap — tighten it and clear the code. If it returns, use a smoke machine to find the leak
- For EGR codes: remove and inspect the EGR valve — carbon buildup causing sticking is extremely common and cleanable
- For catalyst codes: check upstream O2 sensor first — a bad sensor can falsely report low catalyst efficiency
- For secondary air codes: listen for the air pump running during cold start — it should run for 30-90 seconds
Common Mistakes to Avoid
- ❌ Replacing the catalytic converter based on a P0420/P0430 code alone — diagnose the root cause first (O2 sensor, exhaust leak, engine running rich)
- ❌ Ignoring a loose gas cap as the cause of EVAP codes — this is literally the #1 cause and the cheapest fix
- ❌ Using aftermarket catalytic converters in states with strict emissions laws (California) — CARB-compliant converters are required
Frequently Asked Questions
Will I pass emissions with a check engine light on?
Can I just clear the code before emissions testing?
How much does a catalytic converter cost?
What To Do Next
Possible Fixes
- 🔧 Clean or replace EGR valve
- 🔧 Replace gas cap (EVAP codes)
- 🔧 Replace EVAP purge or vent solenoid
- 🔧 Replace catalytic converter
- 🔧 Replace secondary air pump or check valve
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Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.