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what is the temperature outside when e3 happens?
it appears you have a bad outdoor sensor, or the wiring is bad. Usually it is the sensor itself. The E1 is a communication fault. This can be anything from a poor wire connection, high voltage interference (Wire run near fluorescent light ballast) or a bad board.
The highest odds are wiring connections or voltage interference.
Make sure the thermostat wire is run separate from any high volt wires...do not run in same conduit as 120v.....check connections at both ends and reseat. Make sure thermostat wire is not near fluorescent light or other high voltage source.
If issue persist have circuit board checked.
so for now replace outdoor sensor and verify wire connections.
outdoor sensor is E3 code