2008 ULTRA 37.000 miles, showing codes P2122 & P2138 I know what the codes are, but would like some suggestive starting points to diagnose this issue.. thanks in advance.

 

Yes. These codes are set when the twist grip sensor and the throttle position sensors do not agree. This is commonly caused by twist grip sensor and/or wiring/connector issues. See this a lot after internal wiring chafes inside aftermarket handlebars. Also the throttle body connector pins and sockets fret (corrode) and create excessive resistance causing codes and running issues.
hope this helps,
Bob

 

that gives me a starting point, thanks for the help Bob !!

 

Read the attached

 

that's a good read, thanks