2021 Giant Revolt e+ pro - GRX800 Di2 Power level and shifting not working

[Edwin]

I've had a Giant Revolt e+ pro since 2021 and for 3,000kms it has been reliable riding. Well cared for and maintained well. This bike has a mix of Giant and Shimano. EP800 motor, GRX800 Di2 brake/shifter, so the left hand side is for power level and right hand side for gear shifting.

I havent ridden it for a while (since Feb 2025) and today, I turned it on and the bike turned on.

When I tried to change the power or gears with the brake/shifters it did not work. However, when I pressed RideControl button in the downtube, I was able to change the power levels and the bike had assistance so I do not think it's not a motor issue

When I logged into the Giant app, and did the diagnostic, it didnt report any errors. It wouldnt allow for any updates either.

Given that this bike was a one-off from Giant, I am a bit miffed. Surely both brake/shifters couldn't have failed at the same time.

 

[Yetibos]

check if there is the option to set the function for each button. E-shift or somethink like this. Or maybe it is a Shimano issue and you should check it with e-tube.

 

[Edwin]

check if there is the option to set the function for each button. E-shift or somethink like this. Or maybe it is a Shimano issue and you should check it with e-tube.

Thank you. I don't have the cables to do that.

I have taken it to my LBS and they will look into it this week sometime.

The believe its a Shimano issue rather than a Giant controller issue, given that RideControlGo works, the bike can ride and you can adjust the power from the RideControlGo.

Also given that both the LHS and RHS have stopped working makes them think both of those cables go somewhere and that is what has failed!

 

[Edwin]

Update - for those interested.

LBS tried to connect to E-tube on the GRX shifters. No sign of life.

They updated the battery and EP800 motor and still no sign of life.

They took the bits off and put it on the bench and it all worked and they put it back on the bike.

They charged me $133 to resolve it. Ridden 80kms since then. Could have been much worse. Maybe the cable was loose or maybe it fell asleep. Was going to sell that bike and my old Merida E160 10k and buy a Trance Adv X E Elite +0 or new Trek Fuel+ EX 9.8 XT but I'll keep them now.

Moral of the story - ride it regularly.