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Bosch 3-digit error codes

Bosch error 504
Speed signal distortion

The speed signal doesn't look right to the system. Often the magnet on a rear-wheel spoke has moved, or the bike has been tuned to go faster than it should. Assistance is reduced until it's fixed.

Checked against Bosch's own manual: October 23, 2026.

What Bosch says

Speed signal distortion detected. Drive assistance is reduced.

Bosch's recommended steps

  1. Check the position of the spoke magnet and adjust it if necessary.
  2. Check for manipulation (tuning).

Summarized from Bosch Intuvia owner's manual (MY2024, US) (error 504), checked October 23, 2026. Follow the link for Bosch's exact wording.

If it keeps coming back

If the code comes back after a restart, have it checked by a mechanic who works on Bosch systems. Bikes Plus has diagnostic tools for Bosch and most other major motor systems.

Write down the code and what you were doing when it appeared. That saves time at the shop.

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Make sure it's a Bosch code

Error numbers mean different things on different systems. This page covers Bosch drive systems that show 3-digit codes on Intuvia, Kiox, Purion, Nyon or SmartphoneHub displays. Purion displays may show only the last two digits (for example 03 for 503). The newer Bosch smart system shows 6-digit codes instead; look those up on Bosch's site for now.

All Bosch codes Step-by-step checks