From the FAQ thread at the top of this forum...
Similar info in your owners manual too.
The WK2 has an oil change indicator system. This system displays a “Oil Change Required” or “Oil Change” message at appropriate intervals on the instrument cluster. The Oil Change Indicator system uses the Powertrain Control Module to process a variety of inputs and then decides on an oil change interval. The factors which point toward severe use include the following:
* Ambient temperature inputs which indicate extended periods of low temperature operation
* Average vehicle speeds which indicate stop-and-go driving
* Run time which indicates prolonged idling
* Trip lengths and coolant temperatures which indicate short trips
* Engine RPM and engine loads which indicate trailer tow usage
* Fuel indications of an ethanol percentage of 60 percent or greater
The oil change indicator can be reset using the following steps:
1. Turn the ignition key to ON but do not start the engine. If you have the push button start, press the button twice with the key in the vehicle and your foot OFF
2. Slowly depress the accelerator to the floor and release it three times within 10 seconds.
3. Turn the ignition key to the OFF position (or press the push button to turn OFF).