I have a 2004 Grand Am and a month or so ago, I started it up and all the dashboard functions failed. RPM, speedometer, odometer, fuel, temp all stopped working. The dials read zero and the odo did readout but did not advance. Some of the idiot lights also came on. The radio is also dead and is either totally blank or reads “LOC”, but the air blows fine. Also the key fob will not lock/unlock and neither will the door controls lock the doors but the windows work. It was fine the next day. Now it has returned and has lasted 2 days so far.
Full disclosure: I did replace the PCM in December because something in the Passlock system was failing and not letting me start the car. The replacement PCM is an exact replacement that has had the Passlock code commented out. There have been zero problems with the PCM since then.