The main factor for sensor output is spacing, so you have worn down reluctor teeth or a bad sensor.

A scope is nice when you do these b/c then you then see what the Module is actually seeing [ which is why I posted the article]
An ohm value only tells you the sensors coil ohmage for shorts or open circuit and a volt reading tells the Average amplitude. But a scope will tell you every single sine wave chacrteristic of every reluctor hall effect on the sensor. That is what you want to know.
I suspect reluctor height has deminished, just from wear and road rash/ruct. But do not over-look a possible bad sensor...Does the new one match up measurment-wise w/the old one.

Also check that the wheel bearings are not loose..

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A Dalton