The same mileage as which the first cam belt was replaced.
At the same interval you changed it the first time.
80k
Steps to changing the timing belt on a 2005 VW Jetta Wagon 1.9 TDI?
when should I change the cam belt on a 2002 VW Passat 1.8S with 48000 on the clock
serpentine belt diagram for 98 jetta tdi
120.000
250000 miles
60000 miles there is a recommendation that on a TDI the cam belt is changed every 40,000 miles
No milage for replacement is stated recommendation is Check belt every 10,000 miles replace when belt width is down to 22mm.
timing belt
and belt
timing belt