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Ultegra Di2 6770 problem when cold

joem84joem84 Posts: 10
Hi All,
I have an Ultegra Di2 6770. It has worked perfectly for the last 9 years. Now it seems to go to sleep after a few seconds and to wake it up I have to push the button on the front junction box (SM-EW67A) and then after a few seconds, back to sleep. If I leave the bike in the car under the sun, it works perfectly. Or when I brought it to the shop on a warm day, worked perfectly. If I cup the front junction box in my hand for a few minutes, works perfectly until it cools down. The threshold seems to be about 15 degrees.... Doesn't seem to be the other components but not 100% sure but I only seem to have to heat the front junction box.
Has anyone else experienced this please?
Do I need to just change the front junction box? And while I am at it, take the newer version (SM-EW90A)?
Thanks, Joe


  • Having to wake up the bike is usually a symptom of a broken/damaged wire or connector. I would double check these just to be sure.

    If you do change the front junction to SM-EW90A, keep in mind that you will also need to buy two EW-SD50 wires (to both shifters).
    I run - Di2 help / tips / guides
  • joem84joem84 Posts: 10
    Thanks. I have cleaned all the connections except the ones in the frame. Let me try to check the wires.
  • joem84joem84 Posts: 10
    I replaced the front junction box with EW90A and it now works. Remember if you have the old external battery, remove it before doing any updates.
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