Diagnosis of knock control circuit: Notes
The knock sensor signals are evaluated and processed in a custom made integrated circuit CC196. This circuit is controlled by the PCM's processor and the processed signals are directly accessible for knock control and diagnosis.
The build-in knock control circuit diagnostic of the CC196 IC offers three monitoring possibilities: the pulse test, the zero test and parity check. Switching between the pulse test signal, the zero test signal and the signals from the knock sensors are accomplished via a multiplexer.