Press the "Saute" button. Add the chopped bacon. Cook for 3 - 5 minutes. Stir with a long-handled spoon or spatula the whole time to keep the bacon from sticking to the bottom of the Instant Pot.
Add the chopped onion, minced garlic, chopped celery, and diced carrots.
Cook the vegetables for about 5 minutes until the onion is soft and the vegetables are slightly softened. Stir frequently.
Pour in the chicken broth (or vegetable broth or water).
Add the rinsed dried split peas to the Instant Pot. Sprinkle with salt, pepper, and dried thyme, and add the bay leaves.
Close and lock the lid. Move the seal to the "Sealing" position.
Press Cancel to cancel the Saute mode, then press "Pressure Cook" and set the Pressure level to High Pressure, and change the time to 15 minutes. (It will take a few minutes for the Instant Pot to come up to the pressure level before it starts to cook.)
After it has finished cooking for 15 minutes, let the Instant Pot release pressure naturally for about 10 minutes and then do a quick release by moving the seal to the venting position. This will release any remaining pressure.
After the pressure is released and the pin has dropped, remove the lid and remove the 2 bay leaves. Stir the split pea soup.
Ladle the split pea soup into soup bowls. Garnish with chopped cilantro, parsley, or green onions. Enjoy!