The only way to notice a PCS problem without an explicit dashboard notification is to go into service mode and look for active alerts, specifically a message alluding to PCS failure.

In most cases of PCS failure, people see a message on their screen saying 'AC charging unavailable' or something similar.

The RED Review host experienced the exact PCS problem on his own Cybertruck about a year ago.

If a Cybertruck's PCS fails out of warranty, the repair is not cheap.