But before doing anything more be aware that in early model units damaged wiring harnesses can give a LE code. Somewhere on this site there is an article or post referring to that issue.
It is removed from the bottom.
The LE code may be something that clears up: If it's only happened once reset the power and test it in a cycle again.
If you've already done that: I've never seen a jammed impeller but check under the strainer / screen top assmy to make sure the center (wash) impeller is free of trash and turning freely. The upper spray arm tube assmy must be unsnapped from the retainer at the top and back of the cabinet interior. There is a stainless steel clip and screw at the point the assmy sits into the strainer / screen. Remove it and the tube assmy will be able to be removed. It has to removed anyway to remove the sump, should you have to.
If the impeller is turning freely the next step is to pull the dw out, turn it on it's side, remove the cover plate and test the motor in the center of the assmy. That is the wash motor. It is the only motor that is monitored for the LE code. If it is not obviously burned up you will have to run a resistance check on it. That info is available in the serv manual.