hmmm.. Double check the leads on the rx capacitor. I was going to post that you needed one of those as that is the EXACT symptom I had with a savox 1268T/tekin rs until I installed the cap. Ok.. rephrase, not exact. Mine would power up, cycle the speed control showing it was fine, and then I could turn the wheels 3-4 times before it threw the lower power code on the esc.

Cap fixed a "very similar" issue on mine. From what I've been told you can put the cap on any open connection as it just backfeeds it.. although, I DO have mine connected to the bat/bind plug in my rx.

Just double check your cap is in good shape.