Learn the DMTL System! - P0442 EVAP Micro Leak Diagnosis on BMW E90 DIY

The EVAP system on a BMW is slightly different from most other American or Asian cars. It employs something called the DMTL to diagnose leaks on the system. In this video I talk about what that module is and how it works so that you can better understand how to diagnose EVAP leaks.

The codes you might get for EVAP leaks are:

P0442 Evaporative Emission Control System Leak Detected (small leak)
P0455 Evaporative Emission Control System Leak Detected (gross leak)

Both can be diagnosed using this method.

If you're looking to get a good smoke machine, I can recommend this one (which I use in this video):

https://amzn.to/3phMQRS

However the price has gone up since I first reviewed it. AUTOOL makes a cheaper version, but it doesn't have flow or pressure gauges:

https://amzn.to/3mopF6u

There is an even cheaper tool that is made in the USA, however it doesn't look much different than the DIY version I made years ago:

https://amzn.to/32tpvUt

DIY Smoke Tester:
   • DIY Smoke Machine For Vacuum or EVAP ...  

00:00:00 Intro
00:00:23 How EVAP systems work
00:04:39 How BMWs are different
00:07:25 How to test any EVAP system
00:10:09 Where to hookup your smoke machine
00:11:31 Turn on the smoke machine and find the leak
00:12:27 How to close the "vent valve" to seal the tank and find the real leak
00:14:13 Where my leak actually is
00:14:49 Replacing the defective part
00:25:59 Verifying the repair
00:26:57 Wrap-up

This video is for entertainment purposes only. 50sKid assumes no liability for any repairs or modifications performed by the viewer as a result of the information contained in this video.