Bosch 503 error code

[robert]

Is the Bosch 503 error code just a sensor error or the battery too ?

 

[Whitby Chris]

I was under the impression its a speed sensor error? or magnet. I have not heard it been battery related but I could be wrong.

 

[All4Fun]

503... adjust the magnet, distance and centre on the line

I had some problems too, first the gap was too big, adjusted it to 5 mm, again problems, now on 10 mm, until now no problems with 503.

 

[friendlywrench]

Late reply, but I figured I'd leave this here for future reference.

Although the 503 is typically a speed sensor error, there can be a couple of contributing factors that result in the error:

Check Alignment of Speed Sensor and Magnet:
- Ensure the magnet is going over the center of the sensor. Note in @All4Fun's photo that the maximum distance between the magnet and the sensor is 5 - 17mm. However, Bosch advises that the optimum range is less than that, between 8 and 14mm.
- Check alignment of frame. If you have a rear suspension, check links to make sure they are tight and damage free.
- Check alignment of wheel axle.

If you're still getting the error, then it's possible you have a damaged speed sensor or cable and it may be worth picking up a replacement and seeing if that helps.

 

[Oldcreaky]

Late reply, but I figured I'd leave this here for future reference.

Although the 503 is typically a speed sensor error, there can be a couple of contributing factors that result in the error:

Check Alignment of Speed Sensor and Magnet:
- Ensure the magnet is going over the center of the sensor. Note in @All4Fun's photo that the maximum distance between the magnet and the sensor is 5 - 17mm. However, Bosch advises that the optimum range is less than that, between 8 and 14mm.
- Check alignment of frame. If you have a rear suspension, check links to make sure they are tight and damage free.
- Check alignment of wheel axle.

If you're still getting the error, then it's possible you have a damaged speed sensor or cable and it may be worth picking up a replacement and seeing if that helps.

I had the same error code on my Cube, checked the magnet all ok so must be the cable i thought so sent away for one and a crank puller. After receiving both i took the side casing off checked every thing all seemed correct till i pulled at the connector and it pulled out it was not connected only pushed in, it had taken over 3k miles to work it's way out till it disconnected. I pushed the connector in till it clicked and would not pull out, job done. No further problems. It is not always the obvious sometimes, cost me a new cable which i didn't need so that went with the bike to its new owner.