Fuel EXe New Fuel EX-e TQ error

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia
So, picked up a new Trek Fuel EX-E 9.5 yesterday afternoon. Got home, read the doco, downloaded the Trek Central app and went and turned the bike on for the first time to see a ERR 5401 DRV CONN message on the display. Can change screens on the display but all data fields a blank, can't change modes and the app won't pair. Worked fine at the shop when I test rode it and course by now the shop is closed so turn it off (which took 3 or 4 attempts) and walk away. Came back 10 minutes later, turn it on and everything's fine!

Turned it on again this morning just to trundle up and down the street and after a couple of hundred metres the error reappears. Still getting assist but unable to change mode and the display is showing no data.

Grrr. Back to the shop Monday I guess but has anyone else had similar?
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,771
20,455
Brittany, France

About 3/4 of the way down .. could just be a loose cable ?
 

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia

About 3/4 of the way down .. could just be a loose cable ?
Yes, you could be right. Not feeling inclined to start pulling apart a 0km bike though.
 

Mteam

E*POWAH Elite
Aug 3, 2020
1,780
1,718
gone
Sounds like the connector from the display to the motor is not connected properly.

If you want you can just unscrew the bolt that holds the display in the frame, the display then just lifts out and has two cables ,one connect to the motor the other to the controller, just check that these two connections are fully pushed together, it'll take 5 minutes and is v easy to check.
 

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia
Thanks for the suggestions. Removed the display and nothing obvious. All connectors were firmly seated but reseated them anyway. All working afterwards but the issue has already shown itself to be intermittent. Will check the connections in the lower frame tomorrow.
 

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia
Update - checked everything I can without removing the motor and error still comes and goes. Recurred today during a test ride up and down the street, Initially the bike still goes but no display and cannot change modes however after a couple of minutes the motor stopped providing any assistance. Power cycling did not restore function but after leaving for 10 minutes it was working again. Heat related?

Oh well, back to Trek tomorrow.
 

Mteam

E*POWAH Elite
Aug 3, 2020
1,780
1,718
gone
Update - checked everything I can without removing the motor and error still comes and goes. Recurred today during a test ride up and down the street, Initially the bike still goes but no display and cannot change modes however after a couple of minutes the motor stopped providing any assistance. Power cycling did not restore function but after leaving for 10 minutes it was working again. Heat related?

Oh well, back to Trek tomorrow.
There are more connections at the motor end of things that could be loose/not fully pushed in , again its quite easy to get to , but you might be better just letting trek sort it out, as much of a pain as that will probably be.
 

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia
Went back to the Trek outlet and fortunately the error came up as soon as they turned the bike on. Service guy ran diagnostics on the display unit then tried to upgrade the firmware but it failed repeatedly. Ended up swapping out the display for a new one which, touch wood, appears to be working as advertised so far.
 

clivem25

New Member
Mar 5, 2023
37
25
Perth Western Australia
So.... No recurrence so far on my bike but I'm currently on holiday in Derby Tasmania and hired an EX-e for the wife and what happens? ERR 5401 DRV CONN! How common is this?? Still think it might be heat related as bike had been sitting in the sun and the error subsequently went away.

Expensive trip though, she enjoyed it so much she rang up and ordered her own!
 

Cport

New Member
Apr 6, 2023
1
0
Bryson city, nc
I have gotten the same code ERR 5401 DRV CONN! on my last few rides, it is intermittent but now happening more often, I purchased the bike new and have logged about 85-90 hours, its a bummer when it happens in the middle of a ride with friends. As a new eBiker I figured I would have some range anxiety, but now software anxiety on top of that sucks. Worse is all the ribbing from my analog friends ;-). I love the bike when it works. I cannot figure out what brings it on. Sometime occurs right at the start of a ride sometimes later. I could not get to work despite repeated resets and so forth. I took out the battery and reconnected, sometimes that gave me some assisted time but then reoccurs. So far, I have found no loose cables or connections. App is uptodate. I have not taken it back to Trek yet as I live about 90min from nearest Trek dealer but that is next on the list.
 

Pean

New Member
Apr 23, 2023
14
7
Poland
Hello. I have the same problem with the Tq display on the Scott Lumen. The problem is obviously related to heat. Occurs at a temperature above 25 degrees C. I checked it by gently heating the display with a hair dryer and then cooling it down. It's a manufacturing defect. My bike has traveled 60 km.
 

Emailsucks98

Active member
Nov 12, 2020
276
349
Bellingham Wa
As a new eBiker I figured I would have some range anxiety, but now software anxiety on top of that sucks. Worse is all the ribbing from my analog friends ;-).
This topic deserves a thread of its own!
My last bike (shimano motor) threw similar error codes which required a restart. Often got hecKled by analog riders I had just passed. I would accuse them of using an electronics jammer or emitting microwaves.

Never had this error code on my trek personally (going on 7 months now)
 

Kimchisup

New Member
May 4, 2023
1
0
SoCal
Adding to this thread and confirming what others have already shared. Have a brand new Trek Fuel Exe 9.8 and got the 5401 Drive Conn error on it's first ride and isolated it to a heat issue as well. Checked through all connectors and tested leaving the bike in direct sunlight to heat the display to confirm it was the issue.

Haven't taken the bike back to Trek for warranty work yet, but hoping TQ addresses the problem with fixed displays since this seems like a known issue.
 

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