One of the very annoying errors that appear on the screen of electric bikes that have a Bosch motor is the 504 error, which means that the motor has stopped working completely for 90 minutes.
In this post, we will explain the reasons that lead to this error and how to fix it Error 504.
What Is error 504?
Error 504 is an error that appears as a result of the motor’s computer sensing an adjustment in the basic settings for speed, or in a more simplified sense what happens is that the motor senses that its speed limiter is being exceeded so the motor goes to the Limp mode.
What is a limp Mode:
The limp mode in ebike means that the motor will give limitied assistacne under torque
Based on the official Bosch website: This error occurs as a result of a modification to the ebike or a problem with the speed sensor.
Reasons Why Error 504 happened?
Error 504 occurs as “we mentioned” as a result of a problem with the speed sensor or the presence of a tunning that occurred in the bike, but there is a note that must be noted.
Error 504 does not occur when the motor senses a change in speed for the first time, but what happens is that the internal chip of the motor makes a calculation of the average speed traveled by the bike compared to the miles traveled
The process of sensing the speed change takes about 150 km to 250 km, depending on the framework of the motor.
As a general rule, there are three reasons that cause a 504 error, and they are:
A problem with the speed sensor, putting any electronic device to bypass the speed limiter or a problem with the firmware.
1- Problem in the Speed Sensor:
If the sensor magnets are not properly attached to the wheel spokes, this will lead to a difference in the speed readings stored by the motor, which may lead to a 504 error.
2- Installing Device to override speed limits.
When you put any electronic device in order to increase the speed of the Bosch motor, what happens is that this device gives different signals to the motor than the current speed, which makes the motor give you higher assistance that may reach double, but with the increase in miles traveled, the motor will detect this and will give you error 504 and the motor will shut down.
3-Issue in the Motor Firmware.
Another reason that may lead to the appearance of an error 504 is that there is a problem with the firmware of the motor, this situation is not common, and it can be solved by upgrading the firmware (through an authorized Bosch dealer).
How to fix error 504?
As a general rule, a 504 error can be fixed by riding the bike for 90 minutes without the help of the motor at a speed of 7 to 9 km/h or upgrading the firmware.
On the other side:
The crank can be turned using a tool such as a drill to give the motor a signal that you are riding a bike rather than riding a bike without a motor.
1- Riding the bike for 90 MIN.
This method is valid on electric bikes with a modern Bosch motor version of the Firmware because Bosch recently linked the solution to this error with the sensing of both the torque on the rear wheel and the crank
This means that if you have a modern Bosch motor, the only solution for you is to ride the bike without the help of the motor for 90 minutes and then turn the motor off and on.
2- Use a Driller to spin the crank.
One of the widely spread solutions that have many videos on YouTube is to attach a drill to the crank and make the drill spin, which will make the crank move and give a signal that the bike is moving
This solution is suitable for bikes that have a Bosch motor with an old firmware version.
If you did not tune the electric bike and the speed sensor was working properly, then most likely the cause of the 504 error is a problem with the bike firmware
The fix, in this case, is taking the ebike to an authorized Bosch dealer to upgrade the motor firmware
Note: Before going to the dealer, make sure that all the bike settings are set to default so that the seller does not think that there are tunning made to the ebike and take it out of the warranty.
How many times can I fix error 504?
As a general rule, Bosch only allows you to fix a 504 error 3 times.
What happened if exceeded the three times?
In this case, you have to go back to Bosch to send them the motor, and based on the research you did, it is not known whether Bosch will help you with the solution a fourth time or ask you to buy another motor.