Lg microwave displays f-3 - LG LMVM1945 Microwave Oven

Most likely display needs replacing

If the display comes and goes the only fix is to replace the complete control panel, a very expensive part.

If the microwave runs for a few seconds and stops the touchpad might be at fault. This is not common. Generally speaking, if the microwave display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad

Unless you are successful with a hard reset of the elctronics you are SOL and need to get a new control board. Check out the attached for parts Search Over 2 1 Million Appliance Parts

Go for a warranty repair anyway. It may be the magnetron, and the clicking is the big condenser discharging.
https://www.lg.com/ca_en/support/warranty
Microwave Ovens (Over-the-Range):

• 1 year parts & labour
• 5 years on the magnetron (part only)

Microwave Ovens (countertop):

• 1 year replacement warranty
• 5 years on the magnetron (part only)

Since it's less than one year old, it would be fully covered under warranty.

I'd suggest returning it to the dealer or contacting the manufacturer to get it fixed free.

For more Goldstar / LG / L.G. help, call 1-800-243-0000 (M-F, 7am-8pm CT, Sat 8-5 CT) and choose the appropriate prompt from the menu or visit here. You can get warranty info & find a local authorized servicer.

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E-02 on the LED display.

That usually indicates a keyboard error...not a good thing...take it back and get a new one.

Sometimes if the door switches are faulty then the touch panel may not respond. There are usually 3 switches, and I'd recommend if one if faulty replacing all of them as a set. Otherwise it may be a Control Panel fault.

don't try to fix this yourself, faulty microwaves should be repaired professionaly or replaced.

Is it possible someone may have sprayed cleaner directly onto the keypad area?

This causes moisture to get into the keypad and sometimes onto the control board.

This could mean that they control panel frame with keypad (membrane switch) would need to be replaced.

Can you give more details on the cleaning?