P0606 and P069E DTCs

[HateThisTruck]

2008 Silverado w/80kmi threw out the following codes:

 

P0606 ECM/PCM Processor Internal Fault
P069E Fuel Pump Control Module (FPCM) Requested MIL Illumination

 

Truck still seems to run as before the codes and get the same mileage.

 

EFI Live wouldn't clear the codes but pulling a battery terminal did the trick. They did come back after a while.

 

Any ideas what to check?

 

Thanks