2006 Honda Foreman 500FE ES Angle Sensor code 3 at high speed

looking if anyone knows why this happens. This ATV has 500 something hours and 3500 miles has tracks put on in the winter as well. Last October while trail riding with some friends the transmission went into limp mode, since then every time you go faster then 45 mph (it tops out at 55) it will throw a code 3 and wont let you shift (I can still shift manually) untill you cycle the ignition. It only happens in 5th gear over 45mph. The battery is shot in it as well i think and sometimes it dosent like to shift warm or cold. If anyone knows why it does this please let me know.