Diagnosing Code P0444 on my e46...

[Lotsobmws]

My 2001 330Ci is, out of the blue, throwing code P0444. Other than that, it runs flawlessly. However, with the SES light lit, I can't get through Maryland emissions. The conventional wisdom appears to be checking the gas cap first. It's new and clean, so that's out. However, Code P0444 comes on after the first few restarts after clearing prior code(s).

Next likely suspect appears to be the purge valve/breather valve behind the power steering reservoir. The test for it seems to be whether it can hold vacuum at rest/inactivated. If not, it's supposedly faulty. This valve is not that expensive ($80 at FCP).

However, what about the vapor canister and the vapor canister purge valve next to the gas tank? Seems to be in the same emission circuit.

Can the vapor canister or it's purge valve contribute to a Code P0444 condition? If so, are there any tests for the vapor canister purge valve or any way to isolate it as a potential culprit?

Any advice appreciated. Gotta get this thing through emission testing.

Thanks...Lotsobmws.

[Lotsobmws]

Anyone know of the vapor canister and it's purge valve can contribute to a P0444 code or is it just the purge valve on the intake?

Advice/experience appreciated.

Thanks...Lotsobmws

[bimmerlin]

I'm having this issue right now. First it was the 02 sensor throwing codes... (changed that) Cleared the codes. SES light off for three days. All of sudden at the smog station, "you're check engine light came on" I got the purge valve yesterday in the mail, but didn't think I needed to install it. When I got home today from the smog place, ran two scanners and pulled the dreaded P0444 code again. So now installing it is a must for I have a DMV appt tomorrow morning. *Jeez* ...Heard one horror story of a guy installing it and car would not start.

[Lotsobmws]

PROBLEM SOLVED. I just wanted to close the loop on this thread in case anyone else was having this problem. I removed the old purge valve on the manifold (very easy to do) and ran the quick test to ensure it closes and opens properly. It did. However, I installed the new valve since I had already bought it, and crossed my fingers. I purposely did not clear the code to see if the code would self-clear and, if so, how long that would take. Surprisingly, the code cleared in 2 days of daily around town driving. As soon as the code cleared I ran right up to the Maryland State emission station and the car passed.

I'm still not sure why the new purge valve did the trick when the old valve passed the open and close test. Maybe it had a small leak when closed that was construed as a vacuum leak?

In any event, car runs great - it always did - no SES light, 2 years before I have to deal with emissions again, much joy.

Lotsobmws.

[rbelton]

Nice, thanks for following up with your results. Here's the DIY video guide for removing and replacing the purge valve to resolve the P0444 code: