I have been posting a lot lately because I have been trying to get rid of all the bugs in my car. About a month ago I had got DTC 43 (knock sensor circuit) on my car. My car would barely run because of the timing that was being pulled out. My mom was in the process of moving and needed me to get all my parts and tools out of the garage including the car. So, for the mean time I had the knock sensor circuit programmed out until I could get my car and tools situated (which made my car run normal again). Well I replaced my LT4 KS module with another brandnew one, and also replaced the knock sensor in the block. My car still ran like crap and still gave me code 43. I rechecked everything today and the knock sensor gave mr 4,000 ohms, but the when I checked the volts at the KS terminal wiht the igntion on (not running) it read 4.78 volts. Is that what is causing my DTC 43. I read in my Helms that it should be 5 volts, but 4.78 seems pretty darn close to me. I checked it at the back of the PCM when this first happened and I think it was either 5. volts or something a little shy of that. I don't know what else could be causing my DTC 43. Help needed!

Jon

 

Did you check it with the harness connector on the sensor or off? You want ~5V on the harness pin, when its not connected to the sensor. When you connect it to the sensor, you should see 2.5V, and the code will set if the value is outside the range 1.5 - 3.5V.

 

I haven't checked for the volts wiht it connected to the sensor yet. The 4.78 V that I got was from the harness pin when it was disconnected from the sensor. Would that cause the code or is that adequate for the pcm.