I was able to use a Fluke multimeter from work but I’m not sure of the readings.

I access the VSS wire is at the gauge cluster wire harness.

If you have the upgraded radio its also an 8 pulse 5V signal wire at the gauge cluster and in one of the radio wire harnesses.

With a basic radio it’s only a two pulse signal at the gauge cluster so that’s 2 pulses for each rotation of the wheel? Should I see the voltage on for a ¼ turn and off for the next ¼ turn?

DC or AC I was only able to read a few mV. It did increase in scale with the speed of the truck. The best setting on the Fluke was AC with the Hz function on. This gave me half the MPH in Hz. So at 10 MPH, 5Hz was displayed and then 20 MPH was 10Hz and 40 MPH was about 20Hz. This seems incorrect as the Nissan manual states that we should see 240Hz at 12 MPH???

 

Welcome to AAC!

You are unlikely to get accurate readings with a DMM for that application, AC or DC.
You need to use an oscilloscope.

 

Any details would be very helpful. I don’t have access to an oscilloscope but that was what I was thinking. I had seen someone use an oscilloscope to send a test signal to a multimeter and it was able to show a reading in Hz. Just wondering why I seem to see a Hz reading but nothing like the shop manual for the truck would suggest. I’m getting about 5-ish Hz at 12mph while the manual shows that you should see 240Hz. ???

Anyway, thanks for the info.

 

Not sure what vehicle you are working on but most vehicles send an analog or digital signal depending on type of sensor to the ECM and then to the instrument cluster. If it has CAN BUS, you can look at the signal but may not be able to read it. More info like make/model and year would help your cause. I can tell you where you should look if I know that

 

Not sure what vehicle you are working on but most vehicles send an analog or digital signal depending on type of sensor to the ECM and then to the instrument cluster. If it has CAN BUS, you can look at the signal but may not be able to read it. More info like make/model and year would help your cause. I can tell you where you should look if I know that

Sorry, its a 2012 Nissan Frontier. Just wanting to match up what is in the shop manual for the number 5 wire in the gauge cluster harness.

 

240Hz at 20kph doesn't seem right for a 2 pulse VSS.
240Hz is 240x60 pulses/minute = 14,400 pulses/minute.
For a 2 pulse VSS the shaft the VSS is monitoring would need to be spinning at 7,200rpm?
Nothing on your vehicle would be spinning at 7,200rpm at 20kph.

An 8 pulse VSS would still need the shaft to be spinning at 1,800rpm.

The VSS should be mounted to the rear of the transmission?

 

240Hz at 20kph doesn't seem right for a 2 pulse VSS.

The pulse reaching the instrument cluster has probably already been processed by the ECM. 240Hz for the raw reluctor sensor output seems reasonable, depending on the number of teeth on the reluctor ring it is triggered by.

 

So they put info in the shop manual that is a bit misleading? I would think that the value next to the info regarding the number 5 wire with 2 pulses would be the reading expected. 240Hz from that wire at 12MPH???

“For a 2 pulse VSS the shaft the VSS is monitoring would need to be spinning at 7,200rpm?”

I thought it was saying that at 12MPH you would be reading 240Hz. So (I thought) 1Hz is 1 rotation per second and that would be 240 rotations per second. Also, it’s two pulse so would be 120 actual rotations per second at 12MPH? But I’m reading around 6Hz at 12MPH. ???

 

Seems like the 6Hz reading could be correct.

6Hz = 6RPS OR 21600RPH and half that (10800RPH) to account for the 2 pulses per rotation.

Truck tire is about 90” in circumference.

10800RPH * 90” = 972,000Inches OR (1Mile = 63360inches) so about 15Miles an hour.

Maybe?