AC has been woking great for two year. Now has error code E3- evaporator error

have you cleaned filter a regular basis? dirty filters will cause low air circulation. go to long and the evaporator coil is dirty and plugged and will require cleaning. There is no E9 code listed the E5 code describes what you have. Have you been emptying water collection tank?

https://www.lg.com/ca_en/support/product/lg-LP0821GSB

Check the evaporator drain and make sure it is not clogged or holding water in the evaporator pan.

Make sure the condenser and evaporator fins are clean, and that there are the condensate drain hole or hose is not clogged. Also, check the blower or fan bearings to make sure they turn freely without grinding or noticeable sideways slop.

Check the filter on the back of unit maybe dirty needs cleaning

Here are the SoleusAir error codes...
e2 Room temperature outside of working range of unit (too cold).
e3 Faulty coils - Repairs needed.
e4 Internal frost in the unit - Defrost.
e5 General failure - repair needed.
e7 Reservoir full - Empty the reservoir.
If the unit is freezing up (frosting) you may want to check (clean / replace) the filters.

Split AC Lloyd 3star

This often happens when the evaporator freezes up. The freezing temp is not normal and the frost sensor causes an error code. You should open the unit and clean the evap and condensor thoroughly. Let it thaw out if its frozen with ice. Drain the unit. Clean the evap thoroughly. Reasemble and run in fan mode to let the unit dry out. This should fix it 90% of the time. Rarely there will be an actual problem with the sensor in the rear of the unit, you can check the wires leading to the sensor when you have it open for cleaning - sometimes they will be broken when you remove and replace the filter.

E3 error message which apparently means my air conditioneris working so well that it has internal frost. It then stops cooling the airand waits for itself to defrost. So every 5 minutes or so it would stop workingeven if the air temp was above 80 degrees. Also check one of this:
E3 Fault room sensor(s) (open or closed circuit)Code
E3Error detail Remote control transmission error (transmitting error)
Inspected unit Remote control. Hope this will help you. Good Luck.

On your cold side air coming in, does the ductwork have any insulation on it? Also The evaporator (front part, up where your filter is ) may have a plugged drain tube, depending on year make & model. Not uncommon for some to have a cracked drain pan as well. Your best bet may be to pull plastic cover off unit, then look on side of evaporator housing & see if you notice a tube sticking out side for drainage. It may be plugged if there is one there, use a piece of coated wire or similar and try cleaning it ou, carefully, don't ram it in there and hit coils too hard.. You can remove the 5/16" head screws that hold cover over evaporator, and pull that cover forward & have a look as well.

Danby's Consumer Help Line (1-800-263-2629) is always busy. So, I called their General number: 419-425-8627. The receptionist transferred my call to their Service dept. My call was answered in 2 minutes.

The Service Rep. described the following code for my dehumidifier model (DDR657EE):
P1 = Defrosting: the unit will go into Defrost mode periodically to ensure that the parts are working at the right operating temperature. It should be in Defrost (P1) mode for only a brief period of time. If the unit is in Defrost (P1) mode continuously for a couple of hours (or more), then you should call Danby Service for further assistance.

He had no documentation of a P2 code for my model.

He also described other General Codes (applicable to most Dehumidifier/Humidifier models):
E1 = Not enough water
E2 = Not draining
E3 = Water temperature too cool
E4 = Overflow Switch activated
E6 / E7 = Problem with Temperature Sensor

I hope that helps.