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LG Microwave – Why is My Microwave Not Heating?

  • Troubleshooting

At a Glance

If your microwave oven does not heat, it may be caused by the wrong settings or an inadequate power supply. The microwave should display an error code if there is a severe problem which requires a technician.


If your microwave is showing an error code, please visit our LG Microwave - Error Codes article for further assistance.

Try This

  1. Do you see an error code?

    Yes No
  2. Please see our LG Microwave - Error Codes article for more assistance.

  3. Does the keypad respond and the microwave start?

    Yes No
  4. Unplug the unit for 30 seconds and plug it back in. Does the control panel respond now?

    Yes No
  5. Let's Test the Microwave

    1Place a microwaveable safe cup, mug, or bowl of water inside the unit.

    2Press [CLEAR/OFF] or [RESET] to clear the keypad.

    3Press [COOK] and enter [60] seconds.

    4Once completed, check the water to see if it was heated.

    Yes No
  6. Possible Explanation of Behaviors

    • The power level might have been set too low.

    • The timer function could have been activated by mistake which does not heat the microwave, but only works as an alarm.

    • A wrong sensor cook settings may have been used.

    The power level is adjustable by pressing the power button on your microwave. To know more about power level, check the power level table below, or refer to the owner's manual of your microwave. Download a copy of your owner's manual from our Manuals and Document page.

    The nine power levels in addition to HIGH, provide a choice of the best level for the food being cooked. Listed below are all the power levels, examples of foods best cooked at each level, and the amount of microwave power being used.

    Microwave Power Level Descriptions
    Power Level Microwave Output Use



    • Quick heating many convenience foods, and foods with high water content, such as soups and beverages.
    • Cooking tender cuts of meat e.g. ground meat.



    • Heating cream soups.



    • Heating rice, pasta or casseroles.



    • Cooking and heating foods that need a cooking power lower than high (for example, whole fish and meatloaf) or when food is cooking too fast.
    • Reheating a single serving of food.



    • Foods that require special care; such as cheese and egg dishes, pudding and custards.
    • Finishing cooking casseroles.



    • Cooking ham, whole poultry and pot roasts.
    • Simmering Stews



    • Melting chocolate
    • Heating pastries



    • Manually defrosting foods, such as bread, fish, meats, poultry and precooked foods.



    • Softening butter, cheese and ice cream.



    • Keeping food warm.
    • Taking the chill out of fruit.



    • Standing time in the oven.

    To change your power level, refer to your owner's manual for specific instruction for the model of your microwave.

    The timer function is sometimes mistakenly selected instead of cooking function. When the timer function is selected, the microwave only works as an alarm.

    A simple way to detect this is when your microwave's display shows a time counting down, but the oven is not cooking.

    Some microwaves are built with sensor cook; selecting the wrong setting for the sensor cook can affect the cooking time of the microwave.

    Sensor Cook cooks favorite foods without selecting cooking times and power levels. The oven automatically determines required cooking time for each food item. When the internal sensor detects a certain amount of humidity coming from the food, it tells the oven how much longer to heat.

    Quickstep to fixing sensor cook issues:

    • Deactivate the sensor cook or sensor reheat.

    When you deactivate the sensor cook or reheat, check if the microwave will cook with the expected heating temperature.

    If the unit continues not to heat properly, the unit will require service. Please visit our Request a Repair page to schedule service.

  7. The unit will require service for a proper diagnosis. Please visit our Request a Repair page to schedule service.

*Required question

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