I believe a 9E code is low water level error. It could be triggered by low water level, a problem with the float assembly, ( the part on the left side you were referring to) or a clogged hose between the float assy & the wash pump.
This is absolutely correct! It's one thing that is extremely easy to fix. I had meant to create a dedicated thread on the topic, but after some recent travels, I forgot about it.
Remove the dishwasher from it's installed location. Remove the metal cover on the lower left side of the dishwasher (two or three screws, I believe). You'll see two clear plastic assemblies there, which are both connected to each other. They also have hoses connected to them on the rear. The one you need to clean out is the sensor float assembly that is the smaller of the two.
First of all, remove the cover from the left wall on the inside of the dishwasher. This just twists off, but don't loose the gasket! The open and close directions are actually marked on the cover itself in hard plastic. Remove the hoses from the rear of both assemblies, held on by metal clips, as well as an electrical connection. The hardest part about this is the limited access to the area behind those parts. Then separate the two (this can be a bit tricky, but it can be done with a little bit of careful prying and pushing). After that, pry open the sensor float assembly (there are four tabs to be released so that the top can come off completely), but do not break it. Once opened up, it's a simple matter of cleaning it out thoroughly, and that'll be the end of your 9E code.
In some cases, the hollow float itself is to blame, so if you don't see some dirt in there to explain the error, you'll have to find a way to add flotation to the device. Some suggest using glue to hold some polystyrene inside the hollow float, but I didn't have to do this.
The next question will be WHY it was dirty in there. I haven't solved this question yet, but I believe it may the root of all the cleaning problems on these dishwashers. To investigate this, I suggest you remove the cover plate from the drying ventilator on the door of the machine. Is there any filthy gunk in there? If so, you'll have the same problem as me, and maybe we can solve it together.