Speed Sensor Testing
 

The 944 workshop manual says that you can test the speed and reference sensors with and oscilloscope but I am wondering if anyone has tried to test the speed sensor using a digital multimeter and reading the RMS voltage that comes from the sensor when the engine is cranked. The manual says that you should see a 2.5 Volt peak-to-peak voltage displayed on the oscilloscope screen. I'm assuming that measuring this signal with a multimeter and looking for a .884 Vrms signal instead would produce the same test results. Has anyone tested the sensor in this way?

http://forums.pelicanparts.com/uploa...1254361953.jpg

I haven't tried this, but it should work. The only thing that might be a issue is that it is sometimes difficult to measure very low (<1V) AC voltages with a multimeter. And most multimeters measure average, not RMS, AC voltage - not that it would make much of a difference though.