Heymy 95 blazer issetting off P0326, and in my haynes manual it says it's the knock sensor "performance" (rather than fault P0325).Anyone know what the difference is these two codes? Does the sensor just need to be replaced (engine doesn't sound like it's knocking/pinging)?

 

You could have a bad connection related to the knock sensor circuit. Check out the connection at the sensor and all the way back to the computer...

 

The Knock Sensor (KS) circuit consists of two knock sensors connected in parallel and a single wire to the VCM-A. Each knock sensor has a resistance value of about 8,200ohms. The VCM-A supplies a 5volt reference signal to the sensors when, because of the sensor resistance, it is cut in half to about 2.5volts. When a knock occurs, a small AC voltage is generated by the knock sensors riding on top of the existing 2.5volts. An AC voltage monitor in the VCM-A will detect this AC voltage and provide a signal to begin retarding spark until the knock diminishes.

[ol]Turn ON the ignition.
Disconnect both knock sensors.
Using a digital volt meter, measure the voltage on each sensor connector to ground. You should read 5 volts.[/ol]
Also make sure that your knock sensor wiring is routed away from the spark plug wires.
So check your sensors first and see what you find, let us know.

 

Thanks. I'll check and let you know.

 

Ok, I had changed out the plug wires and one had been touching the knock sensor wiring. I moved it and put back in teh little plastic holder doo-hickey and cleared the codes. Hasn't come back since. Thanks for the heads up on the wires Chevy lover.