mr_infamous
Member
If both sensors are the same part, you could try swapping the front and rear sensor connectors to be absolutely sure it's a problem with the wiring or PCM. With reversed connectors, P0327 should set instead, obviously.
I'm more interested in why none of the online FSMs detail how the knock sensor signal is interpreted. My guess is engine vibrations cause the piezoelectric sensor to generate a voltage and an ADC in the PCM interprets the peak voltage of a spike as the "power" of the vibration (worse knock = higher voltage), meanwhile the CPU keeps track of the spike frequency and P0332/P0327 set whenever the voltage spike goes out of range or when fewer spikes are occuring than expected.
Perhaps there's another GM vehicle that uses the same sensors but has more details on the specifics for what a normal sensor signal is supposed to look like?
I'm more interested in why none of the online FSMs detail how the knock sensor signal is interpreted. My guess is engine vibrations cause the piezoelectric sensor to generate a voltage and an ADC in the PCM interprets the peak voltage of a spike as the "power" of the vibration (worse knock = higher voltage), meanwhile the CPU keeps track of the spike frequency and P0332/P0327 set whenever the voltage spike goes out of range or when fewer spikes are occuring than expected.
Perhaps there's another GM vehicle that uses the same sensors but has more details on the specifics for what a normal sensor signal is supposed to look like?