Question: Ladies Tag-Heuer Link Series Issue

My wife's Link series is doing something wierd with the second hand.
The watch continues to keep time correctly, but the second hand no
longer continously ticks. It will pause for roughly 4-5 seconds, then
skip 4-5 seconds on the face. It repeats this same pattern over and
over. THe watch is just outside the two year warranty period, and I
was hoping the battery simply needs to be replaced. However, I have a
Link series that is going strong on 5 years without replacing the

Any ideas or input would be greatly appreciated. Thx.