Low Temperature Loop (LKN)
WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The LKN system includes a low temperature loop that cools the Traction Power Inverter Module (TPIM). The loop contains an auxiliary radiator, air/water separator and an auxiliary water pump. The low temp loop fills through the surge tank and drains by removal of hoses.