Carrera Crossfire E21 Error

[JohnSear]

I know this bike gets somewhat mixed reviews due to the cutting-out problems. After reading lots of online comments I was reasonably happy that the problems are often related to lose connections and often cable ties have seemed to solve the issue. So I went for a 2nd hand one on ebay. Looks in reasonable shape and has the newer LCD display. Apparently only 200miles on the clock (not sure how well that should be believed).

Anyway - all was fine for the first couple of weeks and then the first cut-out with an E21 error. Turned it off and on again and thought all was fine. Unfortunately it's not the case. Every time I turn it on now it just flashes the E21 error.

I can sometimes get it working for a bit if I ride it for a while and then turn on the LCD. The E21 error pops up again after a few minutes - but even then it doesn't feel like the bike is being very assistive. It only seems to kick-in when I pedal hard and even on max support I struggled to get up a big hill which it usually breezes up.

Online people suggest that an E21 error is a problem with the torque sensor. I've tried taking it off - but couldn't see what to clean. Others have said that Halfords can replace the whole part (Torque sensor & crank) for £80.

I've also read that the E21 message refers to: 'Drive Battery over current, low voltage or overvoltage' whereas in another manual that it refers to the Torque sensor.

Any help appreciated to direct me on the right path

 

[Nealh]

Once bitten twice shy in some cases !!!
The system/bike is just not worth the hassle to own and keep trying to get repaired.

 

[vfr400]

The torque sensor is the plastic bit that's attached to the back of the chainwheel. When you take it off you can see little pillars with slots in them where the sensors are. They're more like thin slits. You have to clean them.

One side is an LED, and the other side a light sensor. A slotted ring attached to the chainwheel moves between them, which makes the LED appear to flash to the sensor, so the sensor can judge the rotation speed. There are two slotted rings with springs between them, so as you press on the pedal, one moves in relation to the other to give the affect of shortening the slots. The difference in the length of the light pulses shows the torque applied to the crank.

In simple words, clean the slots.

The other possibility is that the chain came off and nicked the wire, but you should be able to see that.

You can see the dirt on this one, though it wasn't bad enough to prevent it from working.

 

[JohnSear]

The torque sensor is the plastic bit that's attached to the back of the chainwheel. When you take it off you can see little pillars with slots in them where the sensors are. They're more like thin slits. You have to clean them.

One side is an LED, and the other side a light sensor.

View attachment 31057

Thanks so much for your reply & detailed explanation. I'll have another crack at it tomorrow morning. It looked pretty clean to me but now I know what I'm looking for I'll give it a closer inspection.

So given that there's 4 pillars that means there are two pairs of led & sensor?

Does the fact that the E21 comes up straight away tell me anything? More likely that it's a loose / broken wire?

Also, if I plug it all in with the torque sensor hanging off can you see the lights? I guess potentially they are IR.

The bike has been ridden fairly gently under my ownership but it's possible that there is damage from before that was unnoticed. Will give the torque cables a good examination too!

Thanks again

 

[vfr400]

I didn't look at mine when it was switched on. Its probably infra red light anyway. The two pairs are necessary to get the direction of pedalling, otherwise it would set the motor off when you lifted the pedal to get started.

The instantness could be due to one or both being blocked completely. as I already said, it could be a nick in the cable, or there's the possibility of a connector fault.

 

[JohnSear]

Had another crack at this but no joy. I've taken off the torque sensor again. It looks brand new to be honest and the slits are clear.

No sign of lights of any kind. Tried filming with my camera too as this would show up IR - but nothing.

At first I thought there was a nick in the cable but on closer inspection that appears to be the shielding.

I've tried tracing the cables back & they all look good. They run into the base of the battery holder.

Have tried applying gentle pressure on the LCD screen but no luck there and the same with the wires but nothing changes - still an immediate E21 error.

The next point of investigation seems to be the base of the battery. Have you (or anyone reading this) dismantled that? Maybe that end is loose. No idea what the connectors are like in there. Will see if there's anything online before digging further.

Thanks again for your help!

 

[vfr400]

Look in that compartment under the battery. That's where the connectors are. I can't remember what you have to do, but it must be pretty straight forward otherwise I'd probably have remembered how to do it.

 

[JohnSear]

So an update... hopefully this is useful for other users or for future me.

It was a bit fiddly to get the back of the battery holder off. There are 4x smaller phillips screws & they are difficult to get at while it's attached to the bike. So I took off the entire battery holder (remove 3x hex bolts). You can't move it far because of the wires but you can bend it round to make it much easier to remove the 4 screws.

There's pictures of the inside here, incase that helps anyone?

http://imgur.com/a/aao057r

So, inside it all looked good. There were two bits not connected (they didn't go together) - but that seems deliberate.

I disconnected everything & inspected the wires. So completely out of ideas. Connected everything back up again & screwed it all back in place.

Figured I might as well turn it back on & see if I'd made things worse bracing myself for a whole new set of error codes - and weirdly it's all working. No E21. Took it for a test drive up a big hill & it breezed up it as before

So obviously I don't have a huge amount of faith that this won't come back but currently pleased that it is working fine And feel like I know a bit more about how the bike works underneath.

Thanks again for your help Let's hope this thread stays closed for a while!

 

[SycamoreTree]

Not an E21 error but maybe the experts here could help me.

I have the cross fire, bought late 2018, ladies model. In the last week, a problem has developed with the control panel. It won’t respond when I try to switch through the modes, (eg from eco to climb) and several of the buttons on the little panel on the left side don’t seem to do anything now when pressed. It occasionally also adjusts itself to a higher setting when I’m cycling along, without any button pushing , and then doesn’t respond when I try to press the button to move the setting lower.

All wires look well connected and not loose. Is there any kind of re-set that can be done on this little panel? I won’t be able to return it to a store for several weeks and would like to have a DIY fix if possible.

Or is there a manual online anywhere for this model? I wasn’t able to find one in my search and the bike didn’t come with one. Thanks.

 

[vfr400]

A manual won't help. The device is completely electronic using tactile switches as inputs to a CPU.

All the changes to the display are done by the CPU. At the same time as it changes the power level in the display, it sends an instruction to the CPU in the motor controller to change the power or whatever. If the display changed, but not the motor, we could deduce that the problem was the contacts on the back of the LCD unit, but if the display doesn't change, it's a problem between the switches and the CPU. I think we can therefore deduce that the switches are damaged or there's water inside.

I can't remember whether you can open it. Also, there are different versions. If there are screws to open it, have a look inside. They sometimes have sealant around the join, which you have to break to part the two halves after removing the screws.

 

[Nealh]

Being under warranty if you take it back and they notice it's been tampered with, it may cost you more for a replacement.

 

[JohnSear]

Sorry, I know we've moved on from my E21 error but just as way of an update incase anyone else stumbles on this thread.

I had 2 days of blissful E21 error free days before it came back

I suspect there is a loose / broken wire somewhere inside the sensor. Was tempted to cut the wires off myself and resolder a new set. However, I have given up & asked Halfords to look at it. Only option they have is the £90 crank replacement - as it seems the only way to get a new torque sensor.

I'm going with that - will post an update next week as to the result.

 

[JohnSear]

Just a final update. It seems the problem is finally resolved. And it's been pretty happy since. Touch wood!

So the problem wasn't the torque sensor but something to do with the crank. Apparently there are magnets inside the crank that I guess were mis-aligned, loose or something. Perhaps someone who knows more about the inner workings of the bike can shed some light on it.

Halfords first tried replacing the sensor but that made no difference and it was only when the crank was replaced that the problem was solved.

Towards the end of it's troubles - I noticed that when the bike was turned back on after a cut out the speedometer would flash up some ridiculous high-speed - e.g. 63mph. Before returning to 0. I suspect that it was something to do with this that was causing the cut-out.

Anyway - hope this update is useful to someone

 

[Slatey]

The torque sensor is the plastic bit that's attached to the back of the chainwheel. When you take it off you can see little pillars with slots in them where the sensors are. They're more like thin slits. You have to clean them.

One side is an LED, and the other side a light sensor. A slotted ring attached to the chainwheel moves between them, which makes the LED appear to flash to the sensor, so the sensor can judge the rotation speed. There are two slotted rings with springs between them, so as you press on the pedal, one moves in relation to the other to give the affect of shortening the slots. The difference in the length of the light pulses shows the torque applied to the crank.

In simple words, clean the slots.

The other possibility is that the chain came off and nicked the wire, but you should be able to see that.

You can see the dirt on this one, though it wasn't bad enough to prevent it from working.

View attachment 31057

Many thanks for this tip it got me back on the road.I had to use ear buds to clean the metal poles that rotate round as you pedal just dust and I got rid of the E21 error and power came back on.I got rid of the E21 error but had no power then dusted off the outside part of the metal poles and it is fine now...i recommend putting something in the gap where the wire goes into the sensor to stop this happening in the first place.

 

[vfr400]

There are three main problems with these bikes: The torque sensor, the crank seal and the motor connector.

The torque sensor itself is not very robust. It seems to get problems with broken or pulled wires, which you sometimes can't see and the light sensors get dirty, so can't see anymore.

The second problem that affects the torque sensor is the rubber dust seal between the moving and stationary parts on the back of the crank. It perishes or gets clogged and then it jams. When it jams it rotates the stationary part and breaks a luh off the torque sensor. Once the lig has gone, the torque sensor goes backwards and forward until a wire eeventually breaks inside the insulation.

You can also damage the torque sensor wires or break a lug off if your chain falls off.

Another systematic problem is the motor connector. the wires are too tight, which pulls the pins out and breaks the connection. that connector is very problematic. You can mitigate it a bit by pulling the wires together and cable-tying them in that position to keep tension off the connector.

Finally is the cutting out. On the early ones, the LCD was too loose, so you have to add a ship to stop it from moving. Nobody got to the bottom of the battery cut-outs, though it could be related to the motor connector.

IMHO, the pedal sensor arrangement is not up to the job. It will give problems sooner or late - sooner if you use the bike in dirty conditions. For that reason, I'd never recommend these bikes, which is a shame because they've very good when they work.