Hello, I have an 09 hyundai accent, it started running funny and through the p0328 code so I put in a new knock sensor. That didn't work so I checked the wires going to it. It has 2 wires a yellow and a brown both have 2.4 ish volts. I went to the ecu and checked them there to see if it would have 2.4v there as well and it did. Does this mean my ecu is the issue?

 

Unplug the wires to the knock sensor. Connect negative lead of meter to battery neg.
With the key on, only one wire should read approx 5 volts , the reference voltage . What readings do you get?

 

that's what I did and got 2.4v on each wire, the wires dont have continuity either so it's is not the same 2.4v

 

The 5 volt reference voltage is supplied to several sensors on the vehicle among which are; MAF, TPS, KS (knock sensor) ,coolant temp sensor, intake air sensor ,if applicable, and a few others. What is happening is; something is bringing that 5 volts down to 2.4. It could be a shorted sensor or possibly one of their signal wires shorted to ground.
What you might try is to unplug as many sensors as you can find and see if the voltage goes up.
Let us know what you find, thanks.

A defective ECM can do this, but we check and rule out all other possibilities before condemning the ECM.