Di2 weirdness help ...
 

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[Closed] Di2 weirdness help please

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Hi all.
After hours of wet road commuting Di2 has started to play up.
Last week, went to go, seemed like battery dead, so put on charge. Was pretty sure there was loads left when it went away.
This week same again, but I checked an hour before ride. Suspected Bluetooth unit so took it out, and put on charge.
Was okay but after 3 hrs rear mech started to struggle to change up.
Got home, over night charge with seat post out to dry.
Now rear mech won’t work at all.
Front mech fine.
Unplugged and replugged connectors.
Now I suspect water in the junction box at bottom bracket.
I haven’t got at it yet as the tool is at a mates.
Anyone else had similar?
Anything else I should be trying?
I did try plugging rear mech into front mech wire but I’m guessing it would need reprogramming to check the mech this way.


 
Posted : 22/01/2021 11:28 am
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Have you tried fault finding through the App?


 
Posted : 22/01/2021 11:31 am
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Shouldn't need reprogramming as the wires aren't unit specific.

Can you plug the battery, shifter and mech directly into handlebar junction box to verify whether the bottom bracket junction box is the issue?


 
Posted : 22/01/2021 11:31 am
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Slackboy, I would but only have one spare wire, the Bluetooth one.
Sounds like a plan though.
I could unplug the L shifter and put the rear mech into that hole though.


 
Posted : 22/01/2021 11:39 am
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Steviep no I haven’t really used the app. I’ll have a go as well.
Thanks


 
Posted : 22/01/2021 11:40 am
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I'm not sure if it's the app you're talking about, but you can also install the Shimano software on a Windows PC, and then plug it in using the USB charge cable.


 
Posted : 22/01/2021 1:18 pm
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Update, Pc linked up, it doesn’t see the rear mech. I’ve updated everything else.
The Bluetooth module works off the rear mech wire, and the rear mech doesn’t work and is still invisible to the mobile app when plugged into the front shifter port.


 
Posted : 22/01/2021 4:29 pm
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I guess I’ll try and borrow a rear mech off a mate. See what happens.


 
Posted : 22/01/2021 6:05 pm
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Sounds like the rear mech has had it. Maybe try and dry it out thoroughly in the house and see if that helps. Completely different but I had a Mini Cooper s (bmw version - MK.1) and the body control computer would get damp occasionally and bringing that in the house overnight seemed to sort it out.

If not is the mech under warranty? I thought they were meant to be broadly waterproof and able to take most cycling abuse as long as you don’t submerge them in water. I’ve ridden mine in a bit of rain - but commuting went out the window about a month after I fitted mine so it hasn’t seen quite the same amount of bad weather that it would have done normally.


 
Posted : 22/01/2021 7:06 pm
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You sure it’s not gone into crash mode somehow? Think you need to hold the junction button for five seconds whilst spinning the gears.

Crash mode


 
Posted : 22/01/2021 7:19 pm
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Could just be the wire from junction box to rear mech?


 
Posted : 22/01/2021 7:35 pm
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I had intermittent Di2 weirdness on my road bike - ended up figuring it had to be a faling battery but replacing that didn't help

Was a wire that had got crimped somehow and was occasionally losing all connection. I bought a new wire but alos ended up fixing the broken one - they're incredibly simple although I'd worried they'd be complex given how much they cost


 
Posted : 22/01/2021 7:38 pm
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30 year old Dura Ace 7400 with no leccy, still works like day 1. Oops.

It's farkin expensive kit to just fail. Whilst great, not convinced long term.


 
Posted : 22/01/2021 7:44 pm
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Shiiiiit forgot about crash mode. I’ll go try in a bit.
BB junction box seems fine, just had that out.
When I press the front shifter the green and red lights come on then the red stays on. Dunno what that means.


 
Posted : 22/01/2021 7:51 pm
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I had a rear mech die on me like this. It was damaged and a series of very wet rides led to water ingress. Originally strange battery drain but then it packed in all together.

The easiest test is to find a friend and swap connections. Does your mech work on their bike and vice versa. I never found the app that helpful.


 
Posted : 22/01/2021 9:46 pm
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Jonba that sounds like it exactly.


 
Posted : 22/01/2021 10:21 pm
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Tried crash mode, no change, so that’s it, new mech needed.


 
Posted : 24/01/2021 7:26 pm

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