Summary
This function lists both the individual data parameters and the values of those parameters that the selected module receives from another module on the bus. In our example in Figure 2, we selected the BCM section from the main menu. Here we see a list of three data parameters that the BCM collects from the PCI bus that it needs in order to make decisions for the outputs the BCM is responsible for. In this example, the BCM needs to know the Engine Speed, Vehicle Speed and Engine Lamp (MIL requested status) in order to tell the Instrument Cluster what information to display. The information flows for a particular vehicle function is typically stated in the service information System Description section for that function. This scan tool function is necessary in the following and similar scenarios.
Say we have no engine RPM reading displayed on our cluster. Is the cluster assembly defective because it has lost its ability to display a known data value? Is the BCM defective in that it did not send the required data to the cluster assembly? Is the ECM defective because it did not send the requested data to the BCM? Without the above listed Monitor Function, it is sometimes impossible to answer such questions during the diagnostic process. Without this function, we usually will be left with making sure the engine RPM signal got into the ECM and perhaps scanning the ECM to see if it can at least display the RPM signal.See the full content of this document
Extract
Pci Bus Diagnostics
The PCI protocol is a Chrysler specific adaptation of the SAE J1850 specification. The system uses a single wire variable pulse-width modulated signal to communicate between the modules on the vehicle.
The PCI Bu...See the full content of this document
Sponsored links
