Carrera Vulcan E21 error

shabba007

Finding my (electric) wheels
Nov 27, 2021
21
3
I've had this Carrera Vulcan E bike a number of years and done around 2000 miles on it without issue. More recently my chain fell off (lack of oil) and cut right throught the crank sensor cable. This then produced the common e-21 error and no power etc to rear wheel.

I took it to a local Halfords where the bike tech really didn't know much about the bike. However, I left it with them and they swapped the crank sensor. I didn't test the bike leaving the shop (they obviously didn't either). The E21 error is no longer present, however under pedling, the rear wheel motor just doesn't kick in. If I press the 'walk' mode button there is power to the rear wheel and motor kicks in, but never under pedling. This tells me a few things....

1. Rear wheel motor must be ok
2. Possible issue with the newly fitted crank sensor ? Can they be fitted incorrectly ?

Upon mention this to local Halfords they had no further parts or clue for that matter, but did refund the cost of fitting the new crank sensor. However I feel now I'm left with no options other than to try another Halfords, but it seems none of them have parts and perhaps limited knowledge on how to fix these bikes.

Feels like I'm left with a £1200 peice of metal that I can no longer use.

Anyone had any similar experience ?
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
562
78
I've had this Carrera Vulcan E bike a number of years and done around 2000 miles on it without issue. More recently my chain fell off (lack of oil) and cut right throught the crank sensor cable. This then produced the common e-21 error and no power etc to rear wheel.

I took it to a local Halfords where the bike tech really didn't know much about the bike. However, I left it with them and they swapped the crank sensor. I didn't test the bike leaving the shop (they obviously didn't either). The E21 error is no longer present, however under pedling, the rear wheel motor just doesn't kick in. If I press the 'walk' mode button there is power to the rear wheel and motor kicks in, but never under pedling. This tells me a few things....

1. Rear wheel motor must be ok
2. Possible issue with the newly fitted crank sensor ? Can they be fitted incorrectly ?

Upon mention this to local Halfords they had no further parts or clue for that matter, but did refund the cost of fitting the new crank sensor. However I feel now I'm left with no options other than to try another Halfords, but it seems none of them have parts and perhaps limited knowledge on how to fix these bikes.

Feels like I'm left with a £1200 peice of metal that I can no longer use.

Anyone had any similar experience ?
Most days I read the new Pedelec posts, and in my humble opinion ONLY, just from reading those posts, it seems that the more expensive the bike, the more likely you are to experience such problems...Especially when its a few years old.
Being a DIY biker, with electrical knowledge, its always a bonus.....
Some others here have also experienced Halfords "expertise" in a similar way to what you did.....
If you are able to follow help info and have a reasonable toolkit and some electrical knowledge, there are people here at Pedelec that will be more than willing to assist you, and who, most importantly, know your bike model well.....
My personal guess might be is that Halfords may have fitted the wrong sensor, as I do believe that there are several types/styles, though that is simply guesswork on my side. But if you had the original parts still (I myself would have soldered, insulated and repaired the cable itself), someone here might be able to give you more solid advice.....(Always take back the damaged parts, they still belong to you!)
I had a quick look on YouTube and you appear to have a seemingly standard type of rear motor e-bike, which in my humble opinion, should also be reasonably easy to repair with new parts, not necessarily from the OEM.

Reading here on Pedelec, its obvious that most/many/some middle motor e-bikes are apparently far more difficult and far more expensive to repair in many instances, as some use the CANBus, just to stop normal DIY repairs, (or even to stop repairs by LBSs, not affiliated to Bosch), Bosch bikes and similar are well known for this.

I hope that you are put in touch with someone who can help you here on Pedelec.
Remember, cheaper bikes with bog standard parts, are generally easy and cheaper to repair that "top models"....
Best wishes in your endeavors.
Andy
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
We need to know if this is a torque sensor or a cadence sensor ?

Why on earth anyone would comprehend buying an e bike from them or even taking one to them is beyond me.
 
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sjpt

Esteemed Pedelecer
Jun 8, 2018
3,832
2,756
Winchester
Why on earth anyone would comprehend buying an e bike from them or even taking one to them is beyond me.
I'm not a great Halford's fan. However, very few local bike shops offer proper test rides these days; often limited to round the (flat) car park. Halfords do. People here regularly stress the importance of having a proper ride on a bike before buying it, but that is often very difficult.
 

shabba007

Finding my (electric) wheels
Nov 27, 2021
21
3
Thanks for your replies folks. I tend to agree they've probably fitted the wrong sensor. It was the only sensor they had I later found out. To fit it and not even test it is a joke. Unfortunately I didn't the orginal parts back. Thinking now I should have had a go at soldering and splicing

I've seen there are a few on crank sensors Ebay (example below), but no idea if these are orginal parts or not.

 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
562
78
Thanks for your replies folks. I tend to agree they've probably fitted the wrong sensor. It was the only sensor they had I later found out. To fit it and not even test it is a joke. Unfortunately I didn't the orginal parts back. Thinking now I should have had a go at soldering and splicing

I've seen there are a few on crank sensors Ebay (example below), but no idea if these are orginal parts or not.

Someone here will know just how many different ones are around, my guess is maybe 4, but I could be way out. So whatever you have now, cuts that number by one, if someone here (not me sadly!) can recognize it.....
Hopefully there are fewer than my guess, as they are on ebay relatively cheap if I remember correctly.
regards
Andy
PS Ask Halfords for your broken one back, may save you a great deal of "effort"!