If the lightis working correctly,it means you have failed to complete several attempts at a regen. Not really sure how many you have to miss for the light to come on. It comes on continuously when the filter starts to gets a certain percentage full and then it flashes when you are close to full.vexorg said:
You wife's trips amount to four possible regen attempts, so maybe that was enough to make the light come on. I've never had the light come on, so not really all that sure how it works.