P0443 error - what voltage should I have at the sensor?

[syncrocrick]

I am chasing a P0443 error. I replaced the purge valve but I still have the error code.

The old valve reads 31 ohms for resistance. The new one is at 26 ohms.
Is 26 okay? I tested both directly with a 12V battery and they both "click".
So I am assuming they may be good.

However, the voltage coming out in the connector is about 8.5V.
Should it not be at around 12V?

The error comes back as soon as I turn the key (without even starting the engine).

Anyone has any suggestion as to what may be going on?

[oldskewel]

I had a P0444 code on my 2001 3.0i last summer. Replacing the purge valve [13-90-1-433-603 Fuel Tank Breather Valve (evap purge valve)] with a genuine BMW one ended up fixing it.

Prior to that, I mechanically and electrically tested it very thoroughly, with 12V directly, using the Foxwell (pulses it at ~1Hz for about 20 seconds), blowing through a hose to confirm the valve was actually sealing and then opening during all this, measured resistance at 27.8 Ohms. So it seemed perfect in every way, except was throwing the code.

Searching the intertubes, I found many many people who swore by replacing only with Genuine BMW, so that's what I did, and it solved it.

[syncrocrick]

I did a bit more searching this morning and it looks like someone posted a voltage of 11.64V at the sensor. So mine appears to be too low at 8.5V. I am wondering if perhaps the ground is rusted or something else with the wiring.

https://xoutpost.com/bmw-sav-forums/...ses-p0443.html

Also, here are other threads I found:

https://xoutpost.com/bmw-sav-forums/...e-valve-4.html

[syncrocrick]

Originally Posted by oldskewel

I had a P0444 code on my 2001 3.0i last summer. Replacing the purge valve [13-90-1-433-603 Fuel Tank Breather Valve (evap purge valve)] with a genuine BMW one ended up fixing it.

Prior to that, I mechanically and electrically tested it very thoroughly, with 12V directly, using the Foxwell (pulses it at ~1Hz for about 20 seconds), blowing through a hose to confirm the valve was actually sealing and then opening during all this, measured resistance at 27.8 Ohms. So it seemed perfect in every way, except was throwing the code.

Searching the intertubes, I found many many people who swore by replacing only with Genuine BMW, so that's what I did, and it solved it.

Thanks for the info.

[syncrocrick]

All right I did another test. I checked each wire individually with a 12V. The positive seems to bring 12V but the negative only brings 8.5V.
So now I am thinking they may be an issue with the ground. I traced the wire to a box full of wires on the top of valve cover...I need to investigate deeper...

[syncrocrick]

Well...I don't really know why, but it seems to be fixed. I reinstalled the cheap aftermarket new valve I bought off Ebay, and this time I removed the gas cap and cleared the code while the engine was running. That seems to have done the trick, at least for now. I read on a different thread about that trick, but it does not really makes sense to me.

I had also checked a different vacuum valve at the top of the engine and the reading was also 8.5V, so I am guessing that value is okay. Fingers crossed.