The earlier PCMs use a resistor present inside the knock sensor to detect if the sensor is present and connected. I believe this is done using the DC bias of the sensor. Essentially the bias is a voltage generated in the PCM and a series resistor. This bias resistor and the resistor in the sensor form a voltage divider that is measured on the PCM. Should the DC voltage at the terminal be too high, the resistor in the sensor has been disconnected and this generates the fault. Too low a voltage indicates a short to ground.

The later system uses AC to detect connection to the sensor. This is a far more reliable way to go. When the engine is running the vibrations are converted to a signal by the knock sensor. The signal is then processed and tested against two configuration parameters. Too much noise or too little noise produces fault P0332 indicating knock sensor or knock module fault.

To sum up, most of the circuits are exactly the same between early and late PCMs. The knock module and knock sensor along with the software must all be from the same generation. There is probably a way to use various combinations using custom software but it's not worth the time/effort.

-Tom