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Bosch speed sensor fault code

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My wife,s KTM Macina 10 has started to show a fault code 503

 

This relates to the speed sensor on the back drop[ out, and after adjusting the spoke magnet was hoping for the best. But no.

The bike still has Power, but has no speed or distance registering.

 

The fault showed up after a heavy thunderstorm and a good drenching, and after a good look at the unit, it looked like a small crack in the casing, so gave it a spray of WD and tightened it with a cable tie.

 

No joy.

 

Has anybody else suffered this problem, as the unit is not in the direct firing line for a knock from anything, but who knows.

503 is the speed sensor. I would suggest to unplug the speed sensor within the motor. Clean the terminals allow to dry and re-insert.

 

As its Error 503 I am presuming it is a Active / Performance system. Not a Classic+ Line.

 

Also check the speed sensor itself for any damage. It doesn't matter where the magnet it, this will make no difference if the system is not displaying '0' mph when stationary.

 

This means it is not connecting with the speed sensor. This could also be that the head unit is not connecting properly if it is powering up but not displaying ZERO. So take the head unit off. Wipe the terminals and re-apply, just to rule this out.

 

That said, take it back ti the dealer you bought it from, they are their to help you and support in the event of any problems.

 

Regards

Martin

  • Author

Thank you Martin for taking the time out to reply.

 

The bike is an Active line, as you say, and when checking the unit, I did notice a small crack in the casing. When checking if the unit was loose on the chain stay, I made matters worse, as a large crack formed and the unit was almost in 2 pieces. It obviously isn't a 'snap fit' onto the chain stay. although can't see any allan key fittings

 

I have pics of the problem on my Ipad, but cant figure out how to send them to this thread

This means it is not connecting with the speed sensor. This could also be that the head unit is not connecting properly if it is powering up but not displaying ZERO. So take the head unit off. Wipe the terminals and re-apply, just to rule this out.

 

That's what I'd say was the fault, if the display has the retaining screw still fitted undo the 4 mount cap heads, and lift the mount off the bars, then you can access the safety screw to allow you to slide the head unit out of the mount, clean the 7 contacts, also put the screw back in, I don't trust the clip to hold the display in place.

  • Author

Sorry Martin, you mentioned the Intuvia head unit, and Yes, we have cleaned and replaced a few times, as sometimes a bad contact does cause a problem.

And Zero does show on the unit, plus the Eco/Tour etc settings, but spinning the wheel shows no speed and the unit will turn itself off after a period

Thank you Martin for taking the time out to reply.

 

The bike is an Active line, as you say, and when checking the unit, I did notice a small crack in the casing. When checking if the unit was loose on the chain stay, I made matters worse, as a large crack formed and the unit was almost in 2 pieces. It obviously isn't a 'snap fit' onto the chain stay. although can't see any allan key fittings

 

I have pics of the problem on my Ipad, but cant figure out how to send them to this thread

 

Hi,

 

Their is a rubber plug that covers the small allen key bolt holding it to the chain stay.

 

If the casing is cracked it would be good practice to have this replaced. It at least puts it back to factory and rules it out.

 

Regards

Martin

  • Author
That's what I'd say was the fault, if the display has the retaining screw still fitted undo the 4 mount cap heads, and lift the mount off the bars, then you can access the safety screw to allow you to slide the head unit out of the mount, clean the 7 contacts, also put the screw back in, I don't trust the clip to hold the display in place.
Sorry Martin, you mentioned the Intuvia head unit, and Yes, we have cleaned and replaced a few times, as sometimes a bad contact does cause a problem.

And Zero does show on the unit, plus the Eco/Tour etc settings, but spinning the wheel shows no speed and the unit will turn itself off after a period

 

Hi,

 

This is a good thing if Zero is showing as it means the system is still detecting the speed sensor.

 

So therefore I would forget the head unit cleaning, it will now be down to the speed sensor not reading the magnet itself. Is it a standard Bosch magnet?

 

It needs to be aligned with the (very hard to see) small line on the sensor. Not in line with the allen key bolt rubber cap.

 

Hold the bike in the air, re-align the magnet and spin the wheel until you get a reading showing.

 

Martin

  • Author

Thanks again Martin, will check for a rubber grommit covering the allen key fitting.

 

Dare I be so bold as to ask you whether there is easy access though the motor casing to get to the 'live end'???

  • Author

Artsu, the head unit is always removed after a ride, so the original philips retaining screw has been discarded for the time.

 

If the bike is stolen, at least the toe rag will have to pedal it

Thanks again Martin, will check for a rubber grommit covering the allen key fitting.

 

Dare I be so bold as to ask you whether there is easy access though the motor casing to get to the 'live end'???

 

Both the crank arm and motor caisng will need to be removed to access the live end.

 

Maybe a job for your dealer?

 

Martin

Artsu, the head unit is always removed after a ride, so the original philips retaining screw has been discarded for the time.

 

If the bike is stolen, at least the toe rag will have to pedal it

 

That was always my intention too, but mine came loose on the first ride I did without the screw. I perhaps need to take a closer look at the clip on mine.

  • Author

Thanks once again Martin for all your info....

 

So from your comments the fact that 0 mph is showing suggests that the sensor itself is still 'live' and talking, and that the 5-17mm gap and alignment needs to be checked, and that is 'it'

 

The fractured casing of the sensor is a bit of a red herring in that case, and the Bosch magnet, should talk to the Bosch sensor, if aligned, and the gap is between 5-17 mm.....although that sounds entirely too big!!

Artsu, the head unit is always removed after a ride, so the original philips retaining screw has been discarded for the time.

 

If the bike is stolen, at least the toe rag will have to pedal it

What a simple but brilliant idea.......

  • 4 weeks later...
  • Author

Finally my wife's the KTM Macina is back in action again.

 

I was sent a new speed sensor by the country bike shop, and got The Electric Transport shop in Camden, to do the fitting ....easier than packaging the bike up, and couriering it across country

 

http://www.electricbikesales.co.uk/

 

There was the possibility that is was a faulty motor rather than the Speed Sensor, but I think that as Martin said, if the 0 mph is still showing on the Intuvia then the motor is still talking to the US sensor.

 

Nice crowd of guys in ET shop, and pity that they couldn't supply the bike originally, as they had a long delivery lead time, and my wife wanted it yesterday....it cost just £25 to do the fitting, and they also can now do Bosch Diagnostics, and recently been on the Bosch training course

 

They also do an interesting crank drive kit with torque sensor

http://www.electricbikesales.co.uk/shop/images/uploads/thumbs/thumb_sunstar%20ibike%20so3%20pedelec%20system%20400.jpg Sunstar iBike SO3 kit

 

which from the many favourable reviews seems to be a viable alternative to buying a Bosch bike, and converting your own

  • 3 years later...
I am also having problems with a Error 503 on my KTM Macina Tour (2017). It happened once on New Year's Eve but after reading these posts I was able to sort it and it started working after I moved the sensor. However, it may have been a coincidence as I have had the error again today and couldn't resolve it myself. I took it to a local bosch service centre earlier and they said it's also got a 500 error. They also tried moving the sensor without any improvement, and are going to investigate more on Monday - but not good to have such gremlins! Off the road again for a few days which is really inconvenient.

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