[Phil]

What is a ECU?

 

[bnjeep]

Electronic Control Unit I do believe.

 

[Foreman325]

Electric Control Unit

 

[Phil]

what does it do and will prevent my transimission for working? Where is it and would it be hard to replace?

 

[Truegrit]

Tranny not working?? Does it not shift? Check the angle sensor first. If it will not shift.

 

[Robb]

ECU in the Rubicon would be tied to the trans I would think, thats the brains for the automatic.

 

[bnjeep]

I agree

 

[Ramco]

The ECU controls everything on the rubicon including timing Spark, Transmission, and so on. With No ECM bike is a big paper weight.