Well my tach has not been working for a while now. But i do have a code that says tach output faliure. If i put auto tap on the car it tells me my rpm. If i check the tach wire coming out of the computer there is not signal. So what i am asking if i get new computer will this fix it and what could have caused this. There is not grounded out wires or anything. It all started after k member install.

 

The way the PCM reports RPM to a scan tool is different to the Tacho output signal.

How are you checking it?. Oscilloscope??, I guess if you measured it with a multimeter you should see about 4-7VDC.

Do you want a written guarantee??, the PCM outputs are pretty robust and it takes some doing to fry them!!, maybe your tacho is actually crook and is loading the PCM Tacho output down. Can you borrow another PCM first?.

Well, then it sounds like it was not a natural failure.

 

I checked for a signal using a mulit meter i will see if mabe i can get another pcm to check it.