DMTL System diagnosis
 

So after finally fixing my secondary air system code (it was the valve), the SES lights up again.

It was the DMTL pump system, switching current too high, I think?

Reading this overview was a big help in understanding the system, now I'm looking for practical troubleshooting advice.

First thing I did was swap out the gas tank cap with an E46 with no codes. It came back after 2 days, wasnt that.

The DM-TL (Diagnostic Module-Tank Leak) pump is a device BMW puts in-line with the fuel evaporative recovery system to check it for leaks.

It only activates when engine has been off for 5 hours or more, and then run for at least 20mins.

Every second time the above criteria is met, the DME activates the DM-TL pump.

The DM-TL pump works by first pumping air though a 0.5mm opening in the pump assembly. The current consumed by the pump during this phase is saved in the DME memory.

Next, the DME energizes a solenoid to close the opening, sealing the fuel evaporative recovery system. The DME then activates the pump with the system sealed, and saves the current consumed. The DME will now compare the current consumed system open and system closed. Any leak will cause the pump to work harder and thus consume more current.

My code is P1447 - DMTL pump too high during switching. Doesn't make much sense literally, until I stumbled on another description of the code in another forum: P1447 - DMTL pump current too high during solenoid test.

So it looks like it is saying there is a problem while the DMTL pump is preparing to test the system, which points to a problem with the DMTL pump assembly. Many threads with reference to this code seem to end with pump replacement, which seems to support how I understand it.

So at this point, it looks like the DMTL pump assembly to me.

Any DIY instruction on how to replace the DMTL pump for the e53 2002? Want to make sure I have all the rivets and pump before ripping out the wheel well cover.

I replaced mine a couple months ago and it was by far one of the easiest parts to replace I've done. I think you need about 6 rivets and you're good to go. There are how to's all over you tube. Basically you remove the rear drivers side flare, wheel liner and you'll see the pump in the upper rear left corner. The rest is self explanatory. Get the Bosch part off amazon it's the EXACT same part as the genuine OE BMW part. Trust me when I say if I can do it anyone can! I mean that in the most literal sense! :D

Thanks, just what I needed. I installed the running board about 17 years ago on this 2002 and I may still have some of the plastic rivets laying around. I assume I need to get the rivet tool as well. The install looks pretty simple at least from the parts and what people have done on the E70 and X3 just thanks for the confirmation of the E53 location and replacement.:thumbup:

I may be doing this job too. I got the code today. Got a part number?

Aside from that, im trying to rid my engine of oil blow by remnants from before the supercharger was rebuilt. Ironing out the wrinkles, as it were. After I got the DMTL code (189) I also got (4) lambda sensor heater post cat bank 2.