Conditions for Running the DTC
WARNING: This page is about a different car, the 2018 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
P0231, P023F
The ignition voltage is between 9 - 18 V.
P0232
The control enable voltage signal supplied for the ECM to chassis control module is inactive for 4 seconds after engine has been shut off.