Conditions for Setting the DTC
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.
P1B0B
The motor control module detects Negative Supply Isolation sensor voltage less than 20 V.
P1B0C
The motor control module detects Negative Supply Isolation sensor voltage greater than 60 V.