Rebind to the transmitter before you try anything else. I thought I had a bad DX5E transmitter when my CX2 took off flying sideways. I concluded this because the CX2 worked fine when I rebound to its LP5DSM transmitter. I failed to then rebind to the DX5E and instead sent the DX5E off for repair. I soon got it back with a note describing how to properly bind to it. Guess it is a common error.