Code
P0444
Generic
P — Powertrain
EVAP System Purge Control Valve A Circuit Open
Views:
UK: 14
EN: 99
RU: 26
AI status
Completed
Completed
100%
Causes
- Open or broken wiring between PCM and purge valve
- Corroded or disconnected purge valve connector
- Failed purge control valve (open coil or internal break)
- Blown fuse or power supply fault to EVAP circuit
- Poor or broken ground in the circuit
- PCM driver fault (rare)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Failed EVAP readiness or failed emissions test
- Possible fuel vapour smell around vehicle (if leak present)
- Engine may run normally; in some cases rough idle or stumble if valve stuck open
What to check
- Read and record freeze frame data and readiness status with a scan tool
- Verify presence of stored P0444 and any related EVAP codes (P0443, P0441, P0446, etc.)
- Visually inspect purge valve connector and wiring for damage, corrosion, or disconnection
- Check fuse(s) and any relays for the EVAP/purge circuit
- Backprobe purge valve connector to measure supply voltage and control signal while commanding purge on/off
- Measure coil resistance across purge valve terminals with an ohmmeter
Signal parameters
- Supply voltage: ~12 V present on supply terminal (key ON, engine OFF) — verify against vehicle spec
- Control signal: PCM typically switches the ground side or provides a PWM duty-cycle; expected switching when commanded
- Coil resistance: typically around 20–40 Ω for many purge solenoids (check vehicle-specific spec) — open/infinite indicates a failed coil
- When commanded ON, solenoid often clicks and current draw increases; commanded percentage/duty shown by scan tool (0–100%)
Diagnostic algorithm
- Verify code and related codes with a scan tool. Note freeze frame and clear codes to attempt to re-create.
- Visually inspect harness and connector at the purge valve for damage, corrosion, or water intrusion. Repair any obvious faults.
- With ignition ON (engine OFF), backprobe the purge valve connector: confirm one terminal has battery voltage and the other is a PCM control circuit. If no battery voltage, check related fuses/relays and repair supply.
- Command the purge valve ON via scan tool while observing the control terminal: verify PCM provides switching (ground or PWM). If PCM never commands, check PCM and wiring.
- Remove connector and measure coil resistance across purge valve terminals. If resistance is open/infinite or out of spec, replace the purge valve.
- If supply and valve coil are good but PCM control is missing at the connector, perform continuity check from the valve connector pin to the PCM pin. Repair any open circuit or corrosion.
- If intermittent behavior occurs during wiggle tests, repair harness/connector and retest.
- If wiring and valve check OK but control signal is incorrect, test PCM driver output and grounds; replace PCM only after all circuit and component faults are ruled out.
- After repairs, clear codes and perform a drive cycle or EVAP test to verify the code does not return.
Likely causes
- Damaged harness or chafed wire at common routing points
- Failed or disconnected purge solenoid connector (corrosion/loose pin)
- Open coil inside the purge solenoid (infinite resistance)
- Blown fuse or relay supplying the EVAP purge circuit
Fault status
Status
P0444 - EVAP System Purge Control Valve A Circuit Open. The PCM reports an open or missing circuit to the purge control solenoid; EVAP purge cannot be commanded properly.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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