What P0444 means
P means powertrain (engine and transmission). The 0 marks a generic code defined by SAE, so the same number means the same thing across makes. The third character, 4, places it in the auxiliary emission controls subsystem; the last two digits identify the specific fault.
The purge valve (or solenoid) opens to draw stored fuel vapour from the charcoal canister into the engine. The engine computer pulses it and monitors both its electrical circuit and, on many vehicles, the flow it produces.
What “Circuit Open” means here
"Open" means the module detected a break in the circuit — no current can flow. Typical causes are an unplugged or corroded connector, a broken wire, or an open coil inside the EVAP purge valve. Measuring resistance through the circuit from the module connector usually finds it.
What you may notice
Symptoms depend on the vehicle and on how the module responds to the fault. Any of these can accompany P0444:
- Rough idle or hard starting after refuelling if the valve sticks open
- Fuel smell
- Lean or rich fuel trim codes
Where to start diagnosing P0444
- Inspect the valve connector and hoses.
- With the engine off, the valve should hold vacuum when unpowered; one that passes air freely is stuck open.
- Measure solenoid resistance against specification.
- Command the valve with a capable scan tool and listen for clicking.
Clear the code only after recording freeze frame data: it shows the engine speed, load and temperature at the moment the fault set, which is often the best clue to reproducing it.
Live data to watch
These standard OBD2 values relate to P0444. Support varies by vehicle; a value your car does not report will simply be missing.
| Value | What to look for |
|---|---|
| Commanded evaporative purge (PID 0x2E) | Purge duty. |
| Short term fuel trim (PIDs 0x06/0x08) | Should react when purge opens. |
Related codes
Codes from the same EVAP purge valve family. If several are stored together, the shared part — wiring, a common reference voltage, or the component itself — is the place to start.
| Code | Definition |
|---|---|
| P0441 | Evaporative Emission System Incorrect Purge Flow |
| P0443 | Evaporative Emission System Purge Control Valve Circuit |
| P0445 | Evaporative Emission System Purge Control Valve Circuit Shorted |
| P0458 | Evaporative Emission System Purge Control Valve Circuit Low |
| P0459 | Evaporative Emission System Purge Control Valve Circuit High |
| P0496 | Evaporative Emission System High Purge Flow |
| P0497 | Evaporative Emission System Low Purge Flow |
Further reading
Frequently Asked Questions
What does P0444 mean?
P0444 is the generic SAE J2012 code for "Evaporative Emission System Purge Control Valve Circuit Open". In plain terms, it means the engine computer has detected a "circuit open" fault on the EVAP purge valve.
Can I keep driving with P0444?
Usually drivable. A purge valve stuck open can cause rough starting after filling up.
What should I check first for P0444?
Inspect the valve connector and hoses.
Definition source: SAE J2012 / ISO 15031-6 generic DTC definitions. This is the generic meaning that applies across makes; a manufacturer can define a code more narrowly or add its own sub-codes, so confirm against the service information for your vehicle before replacing parts. Written by the OBDAssistant engineering team — see our editorial policy.