Ultegra Di2 rear derailleur does not shift

shooter999

Help!!!

I've just bought a 2nd hand bike which has Ultegra di2 on it. I took it for a spin and all was well.

This morning, I changed the cassette (from a 11-28 to 12-30) and wheels and the gears wore working fine, but needed adjusting.
I was going through the process of re-indexing and all of a sudden, the rear derailer has stopped working. The bike was upside down with me at the time.

The front derailer is still working fine.

I've disconnected and reconnected the battery, but it still doesnt work. I've held down the A button on the junction box and nothing happens.

When I press the shifter to operate the rear derailer It makes a faint ticking noise. but still nothing happens.

Could the cables have cone loose, if so how can I check?

Any ideas on how to fix this?

meanredspider

If you hold the shifter for the rear derailleur across for a second or two, do you get any lights on the junction box (that's how you test battery level in normal circumstances)? If yes, the connection at the shifter is good. If no, the connection at the shifter (either end) is loose.

It's easy to access the shifter connection by rolling up the rubber cover of the shifters at the bars. The connector takes some pushing in so often loose.

The derailleur has a crash protection system - have a read in the instructions about how you reset it (I don't remember(