New Bike. Problem with Shimano speed sensor W101

Pasho

Member
May 7, 2021
9
6
London
Hi All,

Got Vitus E-Sommet VRS for my wife, arrived new few days ago. Awesome bike, but there is an issue with Shimano Steps system.

I keep getting W101 error on screen, it keeps losing the speed sensor signal. This cuts out the assist. For a minute it works fine, then stops, then might come back, might not.

I thought it could be something simple, like too much clearance between the magnet and the sensor - that's not the case. The sensor might ignore the magnet passing right next to it. So it's something with the sensor itself or the wiring.

Any clue how to get this fixed? Must be something simple. I really don't want to post the bike back after all the wait...

 
Last edited:

Dirtnvert

E*POWAH Elite World Champion
Sep 25, 2018
1,348
1,581
BC Canada
Maybe check the plug in at the motor. Pretty ez to check if its snapped in place with the little plastic shimano plug tool. Blow out the hole plug and add some dielectric grease.
You could get a shop to plug in the bike for a diagnostic and/or try a speed sensor that you know is not faulty. Also i recently noticed bikeinn has stock of a bunch of motor parts for shimano and bosch. Pretty sure they had sensors for shimano
 

Pasho

Member
May 7, 2021
9
6
London
Maybe check the plug in at the motor. Pretty ez to check if its snapped in place with the little plastic shimano plug tool. Blow out the hole plug and add some dielectric grease.
You could get a shop to plug in the bike for a diagnostic and/or try a speed sensor that you know is not faulty. Also i recently noticed bikeinn has stock of a bunch of motor parts for shimano and bosch. Pretty sure they had sensors for shimano

Thanks for the response. Checked under the cover, unplugged/plugged - didn't help unfortunately.

I will try to take it to one of Shimano's official service shops. Dealing witch ChainReactionCycles support looks to be a very big pain. I really don't want to send it back after all the wait.
 

Dirtnvert

E*POWAH Elite World Champion
Sep 25, 2018
1,348
1,581
BC Canada
Thats probably the way to go. Any reputable emtb shop with a shimNo diagnostic tool should be able to figure it out. Good luck
 

Pasho

Member
May 7, 2021
9
6
London
Took the bike to Balfe's Bikes workshop a couple of weeks ago. Still there - they've been waiting for the Shimano diagnostics tool. Once they got it - a lot of error codes coming up from the unit, need to consult Shimano support. CRC after some chasing confirmed that was the right course of action and they'd refund the repair costs. More than a months since we bought it and still no clue when it's gonna be ridable...

Looking at the used market I got an impression that warranty motor replacement is quite a common thing with ebikes regardless the make. Quite annoying - you pay around £5k and they sell you a beta version.
 

Richieg

New Member
Jun 3, 2021
1
1
TS26, County Durham
Took the bike to Balfe's Bikes workshop a couple of weeks ago. Still there - they've been waiting for the Shimano diagnostics tool. Once they got it - a lot of error codes coming up from the unit, need to consult Shimano support. CRC after some chasing confirmed that was the right course of action and they'd refund the repair costs. More than a months since we bought it and still no clue when it's gonna be ridable...

Looking at the used market I got an impression that warranty motor replacement is quite a common thing with ebikes regardless the make. Quite annoying - you pay around £5k and they sell you a beta version.
Sadly I come here in the same boat.
I have just returned my santa cruz heckler mx to the supplying dealer with exactly the same issues.
w101 codes with no speed signal even though they have tested the sensor and magnet and they are giving a signal.
I am now waiting for them to send the fault codes to shimano uk for their input on the next move ?
 

Pasho

Member
May 7, 2021
9
6
London
Looks like it's finally fixed. Got a call from the mechanic today. The bike was inspected by an engineer from Shimano. Problem was the magnet (mounted on disc rotor). Shimano guy said it wasn't their native one. Looks like Vitus used something custom. They moved it closer to the sensor putting additional washers underneath and said that did the trick...
 

RustyIron

E*POWAH Elite World Champion
Jun 5, 2021
1,322
2,086
La Habra, California
Just a bit of data for those with problems. Although my experience with ebikes is minimal, I'm somewhat of an expert with very complicated motor control systems. A buddy brought me his very early emtb that was intermittently twitchy. I suspected the magnetic pickup, as well. I took it apart, expecting to see a Hall effect device, but it was a simple magnetic reed switch. I found that surprising, as reed switches can become unreliable. They might work 10,000 times in a row, and then miss a beat. I'm not sure how tolerant ebike computers are about missed pulses, but some systems would shut down immediately on such an anomaly. Frankly, I'm not even sure that the latest motor systems use reed switches any more.

Moving the magnet closer to the pickup is a legit option, as is replacing the magnet. They do become weaker over time. But if a problem isn't resolved after that, it makes sense to replace the pickup. They're cheap.
 

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