I havent' seen that controller or display before, though I have a controller that looks externally just like it, the labelling is completley different as are the connectors, and its' likely the itnernals are different (and so not the same thing, not useful to compare).
So, if E10 is a comm error, really really a comm error,
then it should mean there's a problem talking to or receiving from the dipslay. Since the display has been replaced, then before replacing the controller there is one more test you can try.
There are probalby five pins in the display-controller plug. If so, oen is main battery positive, the other is main battery negative. Another is KSI keyswitch ignition, and the last two are data tx and rx.
A multimeter on 20DCV range, balck lead to bat- whereve ris convenient, can be used to find out which of these pins is which. With display connected and system turned on, probe with red lead on all five pins and write down the pin order/wire color on a drawing fo the conectors, then write the voltage down you see on each one as you chekc them.
When done, turn system off via the display and recheck them on the controller side. Whichever one had battery voltage on it before but doesn't now is t he KSI line. Whichever still has bat voltage is bat+. Whcihever two lines previously had what looked like around 2.5v are the tx/rx lines. The last pin is bat-.
If there are not two lines givieng 2.5v-ish, then that is causing the comm error, mostl likeyl. whichever one its coming from is the one causing the problem.
If you wnat to test witout dispaly to see if it works anywya, power it all off at the battery, then disconnect display, and connect the bat+ wire and the ksi wire on the controller side to turn the contoller on. then turn on battery, and test throttle and pas. if they work, then it means the controller cant talk to the display and get an answer it likes, or the display cant read the controller's signals so it sends a signal to the controller to stay off, and gives an error.
It's still progalby a wire or connector problem causing it, but at least you'll know better which ones to look at.
Those are "JST SM" connectors, and a comon problem with them is that pins sometimes don't click into place right hwhen made, so it looks righ t hwhen unplugged, but pins back out when plugged in. gently pushing on the pins from the mating connection end mfight show any like this.