Conditions for Running the DTC

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

P0C77

Accessory voltage is 9-18 volts at the BECM.
Contactors commanded closed by the HPCM.
The terminal voltage measurement must be less than 60 volts prior to starting the precharge sequence in order for this DTC to run.

P1A20

Accessory voltage is 9-18 volts at the BECM.
Less than 4 hybrid battery voltage sensor faults.