2010 1kd tach signal confusing literature

[gulfcountry]

Hi all
Id like to know which sensor the tacho on my 2010 kun26r 1kd diesel uses for signal.
I have a wiring schematics and on those pages it says the camshaft sensor and the crankshaft sensor are responsible for tach signal .
Im guessing it may only be one but I am only guessing . Anyone able to confirm .

[ptommo59]

Hi Gulfcountry,

The TACH signal is generated by the Engine ECU and as you indicated technically could be based on inputs from the Crank Angle and/or Camshaft Sensors but I don't have access to a definitive source that explains how the ECU works.

However having a quick look at the 1KD-FTV Failsafe Chart if you lose the Crank Angle Sensor the engine will shut down but if you lose the Camshaft Sensor it will only limit power. Based on that I would think that the Crank Angle Sensor is the primary source for the TACH signal as this is required for multiple functions of the engine, transmission, dash gauges, etc.