Incorrect speed readings issue (Bosch)

[meta7]

I've got this issue with the speed sensor (probably) where it basically displays a bad reading. It started a week ago and gradually got worse. Same thing with the motor on or off. I will try to summarise:
Bike: Cube acid hybrid one, Bosch Performance line 2020 motor
Sensor: No error codes, no noticeable movement on the casing, magnet is facing the sensor and is positioned right on the line as it should be, the sensor seems to be correctly plugged in. My only guess is that the wire somehow got damaged under the casing.
Has anyone seen anything like that?

http://imgur.com/a/dPsJmJZ

 

[soundwave]

change the batt in the purion display as it does not charge from the bikes batt and if it runs low will screw up the data sent to the motor controller.

 

[meta7]

change the batt in the purion display as it does not charge from the bikes batt and if it runs low will screw up the data sent to the motor controller.

Would be an easy fix, I'll try that

 

[meta7]

Solved: battery change seems to have fixed the issue

 

[meta7]

Update: so it's putting out random numbers again. I have been on 3 separate rides. During the first two, speed was correctly measured even with the old batteries and after I have changed them to the new ones the speed was still correct so I figured that it's the batteries, but on the 3rd ride it doesn't want to work properly again so I assume that switching or taking the batteries in and out is not a solution (but staying off overnight was?). I have also received a new speed sensor so I will try to rewire that and see if it helps

 

[soundwave]

the only other thing you can do is remove the cable left hand side off the motor give it a clean and see if that fixes it and also do the same for the speed sensor connector.

if it has any warranty left the dealer should replace it.

 

[meta7]

the only other thing you can do is remove the cable left hand side off the motor give it a clean and see if that fixes it and also do the same for the speed sensor connector.

if it has any warranty left the dealer should replace it.

Will try that before switching out the sensor. So your guess is that sensor itself is fine?

 

[soundwave]

it could be the problem but a sensor either works or dont if it is not a bad connection then the display must have a fault.

also check the voltage of the batts as if there is a short it could be draining them fast.

my display never shows the right speed with a dongle so never look at it lol

 

[meta7]

it could be the problem but a sensor either works or dont if it is not a bad connection then the display must have a fault.

also check the voltage of the batts as if there is a short it could be draining them fast.

my display never shows the right speed with a dongle so never look at it lol

Thanks, I've checked everything and none of these seem to be an issue so I messaged the shop and they've agreed to make a warranty claim and replace it.

 

[BazP]

it could be the problem but a sensor either works or dont if it is not a bad connection then the display must have a fault.

also check the voltage of the batts as if there is a short it could be draining them fast.

my display never shows the right speed with a dongle so never look at it lol

Don’t go more than 10 mph and it will be ok.

 

[soundwave]

Don’t go more than 10 mph and it will be ok.

i can get it to 16 tho

 

[BazP]

i can get it to 16 tho

Not with it registering the correct speed.

 

[soundwave]

Not with it registering the correct speed.

yeah i got low mileage as well tho

 

[jeffvance]

I've got this issue with the speed sensor (probably) where it basically displays a bad reading. ...

I have a 2021 Trek Rail with the latest Bosch Performance CX software update, and have a similar problem. Once I get to ~15 MPH, the Kiox display shows random speeds in quick succession. Below 15 MPH it seems to report accurate speeds. Whenever the (misreported) speed exceeds 20 MPH (US limit) the motor cuts off and then the next second when the (misreported) speed is below 20 MPH the motor kicks in. I've changed the boost setting, turned off the motor, removed the Kiox control unit while riding and replaced it firmly, to no avail. How can I determine if the speed sensor is broken? Thanks!

 

[Michael Price]

This may be a bit obvious and unlikely but is there any way another magnet is getting near the sensor - that would affect the reading

 

[jeffvance]

This may be a bit obvious and unlikely but is there any way another magnet is getting near the sensor - that would affect the reading

I don't see how that could happen. At 14.5 MPH all is good and then at 15MPH I start to see all of these speed fluctuations.

 

[jeffvance]

UPDATE: I am wrong about a 15 MPH threshold. Today, the speed fluctuated in the 4-7 MPH range. I think it's probably been doing this all along but I never noticed because a) the speed is low enough that the motor never cut out, and b) usually at these slower speeds I'm not looking at my speed but rather concentrating on the technical singletrack in front of me!

 

[GraemeTrekRail]

Hi Jeff

I got my Trek Rail 9.8XT 2021 late September 20, due to another issue I had a new frame sent to my local bike shop and the bike was rebuilt last week.

When I got it back the bike did the same thing and i wasnt as lucky as i had a massive off as it cut out and on and out and i looked down as you do and then hit a massive root section and superman event happened.... thankfully due to a heart op last year i wear full body armour but still hurts and am black & blue

Also gutted as destroyed my new ergon grips, ripped my seat and heavily scratched my brand new XTR brakes......

Bosch said it was probably the sensor cable, but shop have stripped and said there is nothing wrong with the cable.... so warranty claim to Bosch.

Take your bike back to any trek shop to have a look as it is pretty dangerous position to be in!

 

[jeffvance]

...
When I got it back the bike did the same thing and i wasnt as lucky as i had a massive off as it cut out and on and out and i looked down as you do and then hit a massive root section and superman event happened.... thankfully due to a heart op last year i wear full body armour but still hurts and am black & blue

Also gutted as destroyed my new ergon grips, ripped my seat and heavily scratched my brand new XTR brakes......

Bosch said it was probably the sensor cable, but shop have stripped and said there is nothing wrong with the cable.... so warranty claim to Bosch.

Take your bike back to any trek shop to have a look as it is pretty dangerous position to be in!

Thanks for your reply. I'm still riding my 9.8 regularly and, lately, about 75% of the time there is no speed sensor issue, but I still sometimes have the problem I described above. Fortunately, I have not had the huge boost you did -- sorry about that situation...

 

[GraemeTrekRail]

Thanks for your reply. I'm still riding my 9.8 regularly and, lately, about 75% of the time there is no speed sensor issue, but I still sometimes have the problem I described above. Fortunately, I have not had the huge boost you did -- sorry about that situation...

I would definately take it to a store and claim on the warranty..... it is dangerous around the 25 cut off mark.

Despite that the Trek Rail is just awesome!