I ran my car about 6 months ago and i got a read and said i had really bad knock sensor reading, and that i was getting 8 degrees of retard. I have been trying to get the status on it now. and now the computer says the wire is correct but the pcm is not sending information correctly. how does this happen? its a 93 z28 by the way

 

Not clear on what your question is.

Are you saying that 6 months ago you had DTC 43, indicating the knock sensor circuit was bad, and now 6 months later, the code is gone, indicating there is no problem with the knock sensor circuit?

Or are you saying that you are not able to communicate with the ECM? Are you using a plug-in scanner, or trying to short the pins and flash the codes on the SES light?

 

well i did have the code and replaced the knock sensor. I wanted to hook up the computer so i can see whats going on with my car and now it says that it cannot read the PCM. im not sure if i fired my comp or what. i used pins to figure out that it was a 43 though.

 

did you just get the cable and the computer won't connect w/ the ecm? what brand cable are you using?

 

it isnt the cable.. Because it worked on like 3 other cars. it says there is a connection to the car but the pcm is sending a bad signal.

 

Check ComPort and also if your laptop has more than 1 usb (if you are using a USB adapter) try plugging into one of the other ones.