Why does clock keeps resetting to 1:11 PM?

[Paul Julius]

Greetings,

 

Short Version:

 

Clock keeps resetting itself to 1:11 PM. It will progress in time for as many as 17 minutes, before resetting. Any thoughts on what causes this clock behavior?

 

Full Detail:

 

Our 2004 Cayenne S had varying electrical "ghosts" since we bought it, used, in April 2014. I finally tracked it down to the ground points MB22 and MB23 both having loose nuts. The grounds for all attached electrical components was intermittent, especially in high humidity conditions. For the record, the primary symptom that led to diagnosing the loose ground was the cabin air conditioning/heating system completely losing power. Using the diagram: Wiring Diagram - 25 - Ground points left-hand drive - 9PAAE1 - 2004 - 4, I was able to isolate the ground points. That was resolved in December 2014.

 

Ever since then, the clock keeps resetting to 1:11 PM (or 13:11). All three clocks -- on the radio, near the speedometer, and on the AC/Heat control unit -- display the same behavior. Sometimes one clock will reset just before the others, but only moments before. The clocks are obviously synchronized somewhere.

 

As part of troubleshooting this issue, I replaced the battery under the driver's seat around October 2015. The car contained the original factory battery, prior to that replacement.

 

Any thoughts? Can anyone explain, or point me to the documentation on, how the clock system works? For example, what ultimately controls the "current time" how are all three clocks interlinked?

 

 

- PJ