I've learned that the PCM depends on the sensors to give inputs however each sensor has a "priority" in terms of what position in the loop it sends data to the PCM.
For instancce, in open loop mode, its reading off pre mapped software in the PCM to operate the engine.
In closed loop, it pulls data from O2 upstream and downstream, VSS, TPS, MAP, MAF, CMP, CRM, ECT, Air intake sensor..........et cetera
What I don't know and the FSM does not make clear, is which sensor "ranks" interms of priority. For instance, all OBDII engines will read of the O2 sensors as priority 1. TPS has to figure in there too as does the MAF. QUestion is, which "value" from which sensor takes precedence over the other sensors.
For instance, the knock sensor will only override the CMP sensor when it detects knocking due to excessiv engine vibration. However, it can only go so far to retard the timing after which it pings like crazy.
Next, where does the MAP sensor come into play? What values does it send to the PCM and when does it send them?
I suppose I will have to go glassy eyed and read the manual some more to gain insight as to where the sensors fit into the equation.
SIgh....................
