CODE P1447 DMT PUMP Pump Control Circuit Signal Low

[KRAMCLASSIC]

Hi everyone,

So my SE light came on and my scanner read the code P1447 Diagnostic Module Tank Leakage (DM-TL) Pump Too High During Switching. There wasn't too much info on this forum but I googled and came up with faulty DMT pump as the cause for most, but some have mentioned this could also be caused by a bad gas cap? So I've replaced the gas cap as the first course of action but in case this is not the problem (I always prepare for the worse), I just wanted to know if any of you have encountered this code and what they did to correct it?

thanks in advance as always everyone.

[drwillb]

I had the same thing. Time to put in a new DMTL. Only $60 at FCP and very easy to install.

Just be careful removing the electrical connector so you don’t break the retaining clip on it.

[KRAMCLASSIC]

Originally Posted by drwillb

I had the same thing. Time to put in a new DMTL. Only $60 at FCP and very easy to install.

Just be careful removing the electrical connector so you don’t break the retaining clip on it.

Awesome I'll check out FCP then. I tried to order on Amazon but they won't ship this to California for some reason. Appreciate the tip my good man.

[KRAMCLASSIC]

Originally Posted by drwillb

I had the same thing. Time to put in a new DMTL. Only $60 at FCP and very easy to install.

Just be careful removing the electrical connector so you don’t break the retaining clip on it.

Do I have to relieve any fuel pressure some how before I do this? I've watched some youtube videos but it was for E90 models only, couldn't find any on an E80 Series...any input appreciated..thanks

[drwillb]

I didn’t do any kind of venting. The kind of pressure test the DMTL runs is based on the pressure generated by its onboard pump when pushing air through a .5 mm orifice as a reference.

The only pressurized fuel in the system is pushed by the LPFP and the HPFP. The tank and the evap system are at atmospheric pressure.

[KRAMCLASSIC]

Originally Posted by drwillb

I didn’t do any kind of venting. The kind of pressure test the DMTL runs is based on the pressure generated by its onboard pump when pushing air through a .5 mm orifice as a reference.

The only pressurized fuel in the system is pushed by the LPFP and the HPFP. The tank and the evap system are at atmospheric pressure.

Totally right I was over thinking it. I just got to it and wasn't bad at all. Just had to figure which side it was for the 1 Series (Passenger side). Changing the cabin filter might require more work lol. Maybe 30 minutes tops all in all. Not sure how BMW justifies anymore than 1 hour of labor for this . Now just crossing my fingers that the code doesn't come back.

[drwillb]

The DMTL runs its diagnostic test after every second twenty minute drive, more or less, upon shutdown.

Depending how far you drive it may take a few cycles.