p0017 HARD CODE

Question

2010 Colorado truck had a key on, engine off P0017 code. Once my tech replaced the BCM, went on a road test the code came back on, however my tech was able to clear the code. The tech found the timing chain stretched, replaced the chain, etc. Cleared the code again and the truck runs great.

The question is, since the code was present with a key on engine off and he was unable to clear the code, does this mean that the BCM had an internal failure? If it did, does this mean you have to replace the BCM? thanks