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Hall sensors

Hall sensors





The pulse emitters for the seat are of the Hall sensor type and integral to the motors for the function concerned.

On the motor shaft is a 2-pole magnetic ring (north/south). In the end of the motor is a Hall sensor which detects changes in the magnetic field. When the motor is running, the magnetic changes occur twice per rotation.

The control module supplies the sensor with 7 V through a resistor (100 ohm), mounted in the control module, from the pin on the motor concerned. The sensor is grounded internally in the control module. When the motor is running, the sensor detects magnetic changes whereupon the sensor grounds the pin on the motor via 392 ohm when the south pole of the magnetic ring passes.

The control module detects the voltage change between 7 V when the north pole passes and 5 V when the south pole passes.

The control module counts the pulses and therefore knows how long the motor must run for the seat to assume the desired position.

Diagnostics

If an open circuit/short circuit to B+ or ground should occur in the Hall sensor circuit, a diagnostic trouble code will be generated. The motor concerned, except the backrest motor, can be operated for 500 ms:

B2101

Motor, legroom adjustment

B2106

Motor, seat front

B2111

Motor, seat rear

B2116

Motor, backrest