Shinco E4 Error Code Could be Indoor PCB Problem?

[Mudskipper]

I had a Shinco AC 12000BTU unit purchased last summer, and just start recently for cooling mode and it gave me an E4 Error on the indoor unit.

The technical support guy provided me a trouble shooting procedure, and I figure out it's a indoor PCB problem according to the paper. However, the technical guy on Shinco said it probably a outdoor PCB problem.

I'm a little confused, what's E4 Mean? Is E4 a outdoor PCB problem or indoor PCB, which part do I need to change?

[Mudskipper]

addition:

First summer working with no hassle, I didn't use in Winter. Unplug the system, but didn't put and protection outside. I'm In Montreal, cooold winter.