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Thread: P0444 - can't find a straight answer

  1. #1
    Join Date
    Jan 2018
    Atlanta, GA
    My Cars
    2003 325ci

    P0444 - can't find a straight answer

    This and other forums are full of threads about the P0444 code for the Purge Valve. These threads seem to have three things in common:

    1. "I replaced the purge valve and the code didn't go away."
    2. No clear and agreed upon cause of the actual code.
    3. The threads die without the OP coming back and wrapping up the story.

    I have this dreaded code and I've read (probably all!) these threads. It leads me to two questions I cannot find a straight answer for, but will direct my efforts differently:

    ​Is the cause of this code absolutely an electrical issue? (As the description and many people suggest)
    Can other non-electrical things be the cause? (As many other people suggest - vacuum leak, charcoal canister, gas cap, vent valve (which I cannot confirm even exists on the e46), etc)

    My valve seems to operate fine. When voltage is applied it opens. It is sealed well. There are no vacuum leaks between it and the intake.
    I read 12v on one wire in the connector, but do not have any expensive scan tools that will allow me to trigger the solenoid, and can find no shade-tree procedures for ensuring the valve is getting the correct signal when commanded. (Nor any clear info of when or how it actually is commanded to open.)

    I'll get dirty and get under the car if I can get any clear and agreed upon guidance what to check. This really seems to be a chaotic topic with a glut of information and I simply cannot find dominating good advice.


  2. #2
    Join Date
    May 2010
    Honolulu, Hawaii
    My Cars
    E30, E9, E36, E32
    Sure hope this develops, I have the code too and changed the valve - code came back a few days later.

    One thing I'd suggest is that the monitoring system (the working of which no one has explained) is also susceptible to simpler things than a failed valve, such as a hose that's compromised and leaking. But where has anyone diagrammed the hoses pertinent to the system? Where is the connection to the fuel system made? This info would allow us to get in/under and trace/examine/replace the hoses that may be failing, yielding a fault code even though the valve is good.


    Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.

  3. #3
    Join Date
    Mar 2017
    Norwich, Connecticut.
    My Cars
    Not fully sure either for the code..I have never seen it....but an easy way to discover for a vacuum leak...if this is in anyway connected to this code...wave an unlit 'propane torch' throughout the engine bay area. If there is any vacuum leak in the vacuum hoses..your inline will rev a hundred or two in RPM.

  4. #4
    Join Date
    Dec 2013
    Chicagoland area
    My Cars
    Depends on what the actual codes are, depending on the specific scan tool used.
    First check that the connection is plugged in.

  5. #5
    Join Date
    Jan 2018
    Atlanta, GA
    My Cars
    2003 325ci


    OK so I'm marking this one SOLVED!.

    This one is a big PITA for the do-it-yourselfer. As you can see in many posts, this one doesn't have a lot of possible options for diagnosis. Even when it appears to be "functioning normally", evidently it isn't.

    Tons of research seemed to prove this is solely an electrical problem. Don't waste a ton of time hunting down vacuum leaks or other crap. Concentrate on the connector. If it's nice and tight and clean - replace the valve.

    The solution in this case seems to be just replace the part. (Even if you think the existing one is "ok".)

    Installed the new part, reset all codes, drove it for two days until all Readiness Monitors were set, and no codes! Emissions passed.

    FWIW, the Ohms reading on the "defective" part was 25.4. On the new part it was 25.9.

    Another detail that made me realize I can't effectively test this myself:

    I read that the valve doesn't simply open/close, rather it pulses when commanded by the ECU at 10Hz (10 times per second). Perhaps applying voltage and seeing the valve open on the bench isn't enough when it could be cycling 10 times per second and getting stuck or getting hot or who knows what sort of failure.

    (Non-authoritative source:

    Not necessarily promoting Amazon, but this is the one I bought.

    P.S. believe it or not, noticeable difference in how the car idles. I've spent several weekends smoke testing the system looking for a small leak (my idling STFT was hanging out between +5 and +10). After replacing this part, my STFT swings from -5 to +5.

    I hope this thread helps others like me.

  6. #6
    Join Date
    Sep 2018
    Paso Robles CA
    My Cars
    E 39 530i manual trans
    Being a reasonably experienced amateur mechanic who doesn't like throwing parts at a problem without a proper diagnosis, the P0444 code had me stumped for a few days. The old valve tested good - resistance within spec, closed when cold, worked fine with 12v applied to the terminals. But knowing P0444 is an electrical code, not a "leak" indicator ( that's P0441), and knowing or at least hoping almost nothing goes wrong with the ECU, goatsauce's post made sense. So I ordered a new OEM BMW valve instead of chasing electrical problems, opening up the rear wheel well to look at the evap test pump and lines, all of which would have been a waste of time.

    Also it takes patience to wait for the code to clear itself - clearing it with a scanner gives false hope. Better to let the system go though a few cycles and give you an honest answer. It certainly made my day when the orange light flicked off after the third start up from cold. Any day with no CEL is a good day!!

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