Test Point 21: Speed/Reference Mark Sender - Porsche 944 Workshop Manual

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Test Point 21: Speed/Reference
Mark Sender
This test can only be performed with an oscillo-
scope. Connect and adjust a workshop oscillo-
scope according to the supplied operating
instructions for this purpose.
Connect the positive tester lead via a test lead
on control unit plug terminal 47 and negative
tester lead via a test lead on control unit plug
terminal 48.
Crank engine with the starter motor. Sinusoidal
oscillation of at least 3 volts (speed pulse) and
an applied higher amplitude (reference mark)
must be displayed on the screen.
If the voltage signal is too small (< 3 V), the
distance between the sender and gear ring
could be adjusted incorrectly.
Sender distance: Between gear ring and
sender: 0.8 +- 0.3 mm.
D 24/28 - 24
Fuel System - Electronic Control 944 S/944 S2
1 - Speed signal
2 - Reference mark signal
DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989