Hall sensor detection failed (AWD setup)

Hi guys,

I have an AWD (All-Wheel-Drive) e-board (10S5P / FocBox / Maytech 5065 sensored 220kv : see setup below).
After some 40km of ride without any issues and visible damages on any electrical component (motor, wires...),
I started it the next morning as usual and it began suttering : slow motion / normal / slow motion  / normal.
I checked the four motors and one had a temperature quiet higher than the three others (the front right one).
I decided to check this motor with the bldc tool and the "Start Detection" made the motor spin normally,
but returned a "Hall sensor detection failed" (see detail below).
I made also a "Start Detection" of the front left motor to compare with, and it made the motor spin the same,
yet it returned a correct result with a "Detected hall sensor table" (see detail below).
Then I saved as xml the firmware configurations (of focboxes) of both motors, to compare them and maybe find something...
As you can see below, the xml hall sensor table of the faulty motor has "good values", that is : not the ones
returned now by the "Start detection" which are bad -1 values; and the xml hall sensor table of the good motor
is the same as the one returned now by the "Start detection".
So I conclued that this xml hall sensor table of the faulty motor, is the one that was written in the firmware
after a correct "Start detection" when the board was built.

From this I made the following hypotheses :
  A : the sensor wire adaptor is broken somewhere;
  B : the motor sensor wire is broken somewhere;
  C : a motor sensor is broken somewhere;
  D : something changed over the time between the focbox and motor, making the current firmware configuration obsolete...

For hypothesis A : I interchanged the adaptors of both motors and "Start detection" still returns the same : so this hypothesis is canceled.
For hypothesis B : See motor photos below : all are not that good, yet no visible damage,
and according to an electronics guy : a continuity check of each cable is quiet impossible due to the way they are connected in the motor.
I doubt hypothesis C can be checked...
I have no clear ideas how/if hypothesis D can be checked.

So if you guys have ideas to further check some of these three last hypotheses it's cool,
otherwise just a vote on which part(s) to replace is welcome : without further checks (and/or votes),
I will replace the motor by a new one of the same model.

A last point : the 7th value of the failing sensor table detection is 1, whereas I read everywhere that
this value should always be -1 (or 255 which is the same in the firmware internals).
May be this 1 value instead of -1 can give further informations about the problem...
... and by the way : if someone can give the mapping between these values and their role its cool, I mean :
<hall_table_1> is the detected ground cable ? dtected voltage cable ? detected temperature cable ?
<hall_table_2> same question
etc...

Thank's to have read my post anyway !

Franck

All-Wheel-Drive setup :
https://drive.google.com/open?id=1dUzzwHplBlBZniYbRBQGiHbisCsLHuUs

Motor photos :
https://drive.google.com/open?id=1EH46MGEru5Br2-u1LEF-71_wv-OfyOaY

Bldc tool start detection of faulty motor (Sensor mode : hybrid):

  - Detect parameters :
    Current : 6,00 A
    Min ERPM : 600,0
    Low duty : 0,05
  - Results :
    Detection results:
    Integrator limit: 106.65
    BEMF Coupling: 858.81

    Hall sensor detection failed:
    -1, -1, -1, 4, -1, -1, -1, 1

Bldc tool start detection of good motor (Sensor mode : hybrid):

  - Detect parameters :
    Current : 6,00 A
    Min ERPM : 600,0
    Low duty : 0,05
  - Results :
    Detection results:
    Integrator limit: 96.55
    BEMF Coupling: 839.77

    Detected hall sensor table:
    -1, 6, 2, 1, 4, 5, 3, -1

Saved xml configuration of FocBox of faulty    motor (= hall sensor table detection when the motor was ok) :

    <sl_bemf_coupling_k>800</sl_bemf_coupling_k>
    <hall_table_0>-1</hall_table_0>
    <hall_table_1>5</hall_table_1>
    <hall_table_2>3</hall_table_2>
    <hall_table_3>4</hall_table_3>
    <hall_table_4>1</hall_table_4>
    <hall_table_5>6</hall_table_5>
    <hall_table_6>2</hall_table_6>
    <hall_table_7>-1</hall_table_7>

Saved xml configuration of FocBox of good motor (matches the detection above) :

    <sl_bemf_coupling_k>850</sl_bemf_coupling_k>
    <hall_table_0>-1</hall_table_0>
    <hall_table_1>6</hall_table_1>
    <hall_table_2>2</hall_table_2>
    <hall_table_3>1</hall_table_3>
    <hall_table_4>4</hall_table_4>
    <hall_table_5>5</hall_table_5>
    <hall_table_6>3</hall_table_6>
    <hall_table_7>-1</hall_table_7>

Parts references :

Maytech motor model :
https://psychotiller.com/product/custom-maytech-5065-sensored-220kv-motor

FocBox motor controller :
https://www.enertionboards.com/electric-skateboard-parts/FOCBOX-programm...

Bldc tool :
https://www.enertionboards.com/new-focbox-speed-controller/focbox-bldc-t...

Posts found with similar issues/topics :

https://www.electric-skateboard.builders/t/unknown-hall-error-255/37058

https://vesc-project.com/node/85

https://www.electric-skateboard.builders/t/hall-sensor-detection-failed/...

https://www.electric-skateboard.builders/t/hall-sensor-detection-has-fai...