Stu

My clock is starting to fail to keep proper time.
Last oil change the guy told me my battery is not very strong. Surprised to hear this as its a 2 year old battery and the car starts and runs fine.

Obviously I plan to replace the battery but is the clock even a related issue ?

Gene01

Monitor the battery voltage either with a voltmeter (note that the cigarette lighter socket is not powered with the ignition off. Or use the diagnostic screen in the display unit.
If running, you should have 13.8 V or above. With the engine stopped, it should be about 12.6 V.

StanVanDam

The clock in my 2002 synchronizes to GPS as soon as I pull out of the garage and lock onto a GPS signal (blue GPS icon lights up on the nav screen). If you are playing around with the nav unit in the trunk, double-check that all cables are installed and seated properly. Use the nav diagnostic screen (on the language select / I Agree screen, tap upper left, bottom left, upper left, bottom left, bottom right) to check GPS signal quality and voltages.

If you don't have a nav unit:

The clock specification is +/- 1.5 seconds per day, and the allowable error is +/- 2.0 seconds per day.
1) Check battery voltage - should be 10-16V when the ignition switch is ON with the engine OFF
2) Check clock adjusting button to see if it is stuck
3) Check the clock harness, voltage across B+ (pin 4) and body ground should be 10-16V
4) Check voltage between ACC (pin 8) and body ground, should be 10-16V

If voltages are below 10V, locate cause and repair, or recharge battery. Otherwise, clock assembly needs to be replaced.