P0444

P0444 is a more specific variant of P0443 indicating the EVAP purge valve circuit is showing an open condition, meaning the PCM driver pulled the control line low but did not see the expected current draw, signaling an open coil or broken wire. Cheapest checks: disconnect the purge valve and measure resistance across its terminals; the coil should read 22 to 30 ohms on virtually all modern domestic and Asian purge solenoids. Infinite resistance confirms an open coil and a failed valve. If the valve reads in spec, the open is in the harness or PCM driver: back-probe both pins at the valve connector with the connector unplugged and the key on, verify battery voltage on the feed wire (typically through the EVAP fuse), then reconnect and use a scan tool to command the valve while measuring the control-side voltage. With the valve commanded on, the voltage should drop near 0V; if it stays at battery voltage, the PCM is not pulling low (driver fault) or the wire is open between PCM and valve. Wiggle-test the harness with the valve commanded continuously and watch for intermittent code re-set. Caveat: a P0444 set in cold weather only often points to a hairline crack in the solenoid coil that opens when contracted, so warm-engine resistance tests can read fine; test cold if the code is weather-specific.

Vehicle-specific patterns: 2000 to 2007 Chevrolet/GMC full-size trucks set P0444 from open purge valve coils, GM TSB 04-06-04-038 documents the part-number supersession. 2004 to 2009 Ford Focus/Escape with the 2.0/2.3 Duratec trips P0444 from purge valve harness chafing on the valve cover, breaking the control wire. 2003 to 2007 Honda Accord V6 sets P0444 from open winding in the canister purge valve, often after 80k+ miles. 2005 to 2010 Toyota Tacoma/4Runner sets the equivalent VSV open code from the EVAP VSV coil failing, Toyota TSB EG024-08 covers the updated VSV. Estimated repair: $80 to $260.