LG WM3431 washer/dryer combo recently stop drying clothes in the middle of the drying cycle.

SOURCE: "CD" ERROR ON LG WM-3677HW Front Load All-in-One Washer / Dryer

CD means cool down, press the pause start button, the door lock will open. It is an anti crease cycle. It mentions it in the owners manual, but it is hidden deep in the drying section.
Sgt 48

SOURCE: My LG WM3431H All-In-One Washer and Dryer won't dry

Thanks to CoolTech for pointing me in the right direction, I just finished a full clean out and diagnostics test and my dryer works once again.

This repair isn't rocket science nor is it a good idea for the mechanically timid. I managed to get the critical parts out for cleaning and back in properly with just a phillips head screwdriver and a pair of pliers for the spring type hose clamps so it's not a matter of custom tools.

You have dig pretty deep and remove an awful lot of cabinet parts, fans, heater assemblies and something like 30 or 40 various screws to get to the condensor duct and bellows to clean them. Sure enough my condensor duct was jam packed with lint. Once removed I was able to clean it with a creatively bent coat hanger, but a semi flexible bottle brush/pipe cleaner about 18 inches long and an inch or so brush diameter would be a better tool.

If you want to tackle this job, and again it sounds daunting but isn't to someone with reasonable mechanical skills you should do yourself a favor and buy a copy of the factory service manual. I got mine on line from these guys: http://www.manualuniverse.com/ but there are probably other sources including LG if you search by the model number.

In addition to some less than obvious disassembly instructions the manual tells you how to trigger the self test mode and how to interpret the results, gives you good information on cold state resistance tests you can do on relays, heater elements, sensors, etc. and provides a good troubleshooting guide for a variety of problems.

All in all the job took me about an hour and a half and was pretty straightforward except for the last mounting screw for the condensor duct which is hard to get to and requires some effort to remove and replace but again I did the whole job with a standard medium sized screwdriver so it's not impossible.

Good luck and if you're having this problem and like me you don't have any local repair folks who'll touch it (not many of these all in ones in Wyoming) then I'd get your hands on the manual and dig into it. It's not fun, but not too hard either.

-Dave

SOURCE: LG Tromm WM2496HWM Washer - stops mid cycle

use only HE (high efficiency ) soap,try not to use too much ,run tub clean cycle with a little bleach to kill smell

SOURCE: Washer-dryer # wm3677HW will not dry,heats up, run, on and on

You're a moron. This unit washes and dries. That's the whole point of it. Perhaps you should do some research before answering the question. the most likely cause is the water lever sensor.

SOURCE: LG Senseclean washer dryer combo won't dry

The problem is likely due to lint build up in the condensing unit. I found a solution here:
http://www.motusconnect.com/blog/2009/1/5/lg-washer-dryer-drama-%E2%80%93-diy-fix

I also had a softball size ball of wet, packed lint in the condensing unit. I found that the unit can be cleaned without tools or dis-assembly by:

1. draining the water.
2. laying the washer on it's back.
3. removing the hose clamp on the rubber bellows that connects the drum to the condensing unit (right hand side of machine).
4. digging the lint wads out with your fingers and a small screwdriver.