I have a 2012 Bluebird all American with a cumin's engine .The filter change light came on . I have never changed the filter and just reset so the light would go off . I always thought these reminders were mileage related ? Is the transmission detecting a drop in pressure ? I used J Pro and reset the filter reminder and it goes off and then I start the bus and it comes back . So I used these two codes reset . N R N R D N and then N D N D N R N do I really need to change the internal and external to reset the transmission ?
When that light comes on, you should change the external filter. I'm pretty sure it's just a screen on the internal. Be mindful to take the magnet off the top of the filter and put it on the new one. I can't tell you how many times I didn't even think about it and just threw it out with the old filter. Once it's been changed, you can use this to reset the light: N-D-N-D-N-R-N Make sure you pause a moment in between each shift.