Crankshaft sensors

Forum for Infiniti M37, M56 M35h Hybrid and Q70 owners.
Lahjj616
Posts: 10
Joined: Thu Dec 24, 2020 11:39 am
Car: 2011 Infiniti M56

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Is there anywhere in the manual that shows the readings for good crankshaft sensors. I cant find anything. Trying to test with a multimeter


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VStar650CL
Technical Expert
Posts: 8291
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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Three wire sensors (Hall Effect types) produce square waves at either a 5V or 12V rail voltage (most late model N/I engines use 5V). N/I engines generally have a 32-minus-4 format on the crankshaft where there are two packets of 16 teeth with two 2-tooth index gaps for each revolution of the crank. Because of the index gaps and the mechanical asymmetry of the teeth, it's difficult to tell anything meaningful from a multimeter. You'll usually get something that's a bit less than half the sensor's rail voltage, but that will only tell you the sensor isn't stone dead. It won't clue you to a sensor that's missing teeth. You really need a scope to see what's going on when a CKP or CMP sensor is misbehaving but not dead.

Shanehsmp
Posts: 107
Joined: Mon Mar 13, 2017 1:37 pm
Car: 2006 Infiniti M35x - Sold
2012 Infiniti M56x
2016 Infiniti QX70s

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Page EC-1071 shows what the waveform should look like with an oscilloscope. I purchased one off of amazon for 50$. The voltage output will still be 4 to 5V, the frequency of the wave just increases as RPM increases.


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