"Key in pocket" entry only works for a minute.
 

I've had this '04 TDI for over a year and the key in pocket entry has never worked right. I get the following Permanent DTC codes:

Left Access/Start Authorization Antenna-R134 Interruption
Right Access/Start Authorization Antenna-R135 Interruption
Access/Start Authorization Antena in rear bumper R136 Interruption
Interior Access/Start Authorization Antenna 1-R138 Interruption

If I clear the codes I can get the system to work fine a few times but after I go for a ride, it quits again. Any ideas as to the cause and how get it work all the time? Could it be bad coding in the kessey? If I can get it to work, I assume the antennas are good.