brose drive S display says "no motor"

fm4711

New Member
Jan 27, 2025
2
0
USA
Hi!

My wife's Specialized Como 4.0 has a Brose Drive S, which stopped working. On power-up, it shows "no motor" on the TCD.
All wires have been checked for contact (by both me and the shop), they say get a new motor for $$ (out of warranty after 2.5 years).
To me, feels like a sensor problem b/c bike hasn't been used that much, and when I opened the motor, it's clean (no water), belt and planetary gear is in great shape, main board shows no burned out components (very clean). Did anypone have this before? Maybe the torque (ring) sensor or hall sensor?

I hear that replacing circuit board is no option since it's custom programed not just for Specialized setup but also to fab differences in rotational/gear elements, if that's true?

Might have to send it off from NC to TN to Michael for repair, or even order a new one for $$ unless someone has a hint.

BTW, I did measure resistance over 3 motor contacts, they are identical.
Is there a way to test torque/hall sensor w/ multimeter as well, maybe even w/o removing from circuit board?

Any help welcome.
 

mustclime

Active member
Apr 19, 2023
504
394
New Jerzy
This may be way off base but have you removed the battery and cleaned the connections really well. I don’t know if it was the motor resetting from the battery removal or the cleaning but I had the same error that cleared after I did this.. make sure to really really clean out the pin hole connectors in the charging door.
 

fm4711

New Member
Jan 27, 2025
2
0
USA
Interesting thought, thanks for the input, here's what I did:

Battery connectors are clean but I'm a bit puzzled by the voltage readings:
Removed battery, measured 6 pins as: ground, 38, 39, 28, 0, 41V. Are these readings of cells in a parallel circuit? Are there 4 such cells or 5? The 0V readings is strange.

Battery to motor connector also has 6 pins. 4 of them show connection (incl. main ground and +41V to drive motor), but two other pins are *not* connected from battery terminal to motor terminal.

Does anyone have any data on this?
 

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