Checking the Speed Sensor

Checking the [1][2]Speed Sensor:




Disconnect control unit.

Measure resistance of [1][2]speed sensor. It must be between 0.65 and 1.6 KOhm.

Check pulse wheel for damage, freedom of movement and eccentricity defect.

Connect oscilloscope from BMW Service Tester as follows:
- Terminal D+ blue to [1][2]speed sensor signal
- Frequency (-) black to [1][2]speed sensor ground
- Frequency (+) blue to terminal 1 black

*M* 13 Select frequency and enter 80 Hz

*M* 22 Select oscilloscope

Evenly turn wheel by hand. A sinusoidal curve should appear whose amplitude and period duration are dependent on the rotary speed. (See example in drawing.)

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*M*: Multimeter; Select multimeter on the BMW SERVICE TESTER. Select indicated multimeter function.