PCMCOMM
	  The communicator for your '94-'95 LT1
                      Version 2.0

This program is for Windows95 and above operating systems. Minimum 
hardware requirements are a 486 PC with 16MB RAM. Program hard disk 
size is tiny (about 60k). Also need one RS232 serial port, and an ALDL 
Port to RS232 converter. A schematic is available at this website also. 
This program is not meant to commercially compete with programs like 
Diacom, but it is merely intended to provide similar functionality at a 
drastically lower price. It is the result of a hobbyist's 
experimentation with his car's computer, and should be viewed as such.

This program will allow you to view engine sensor and PCM (Powertrain 
Control Module) parameters real time as your motor is running. With 
such readouts as Oxygen Sensor Voltage, Air Flow Rate, and Knock 
Retard, this program can aid you in tuning your motor for maximum 
performance. Or it can allow you to be cool and ride around with a 
laptop in your passenger's seat like the rest of us. ;^)

When you start the program, the parameter display window will appear. 
At this point, the program is waiting for you to initiate connections, 
etc. The first thing to do is to check the COM port on your PC, and 
make sure that you're connected to the right one. When you click the 
*Settings* Menu, a dialog box will appear where you can select the 
proper COM port. For troubleshooting purposes (or Cone Shaped Hat 
gratification <|:^) ),  you can enable the "Display Comm Data" function 
to watch the protocol interaction. When you enable this display, you 
will be able to click and drag up the lower edge of the main window to 
make the diagnostic windows appear. This is where this Comm Data will 
be displayed.

At this point, you are ready to connect to the PCM. *Action* *Connect* 
will start the readings (assuming the key is "on" and the interface is 
plugged in). The program will pull the VIN of the PCM and display it, 
as well as the real time engine and sensor data. (VIN is useful if you 
have purchased an ECM from a scrap yard and do not know what kind of 
car it came from. VIN decoding tools are available on the internet. See 
http://www.f-body.org (Z28/Formula/Trans-Am), http://www.theherd.com 
(Caprice/ImpalaSS), http://www.y-body.org (Corvette)).

For advanced users, you can log your data acquisition run by selecting  
*Log_Run* from the main menu bar. This could prove very useful during 
those quarter mile dashes when you don't need to be looking over at the 
laptop. ;) When you select this option, a Save As... box will appear 
and you can create a file name to save your data.

For those wearing the CSHats, you can use the *Log_Utility* to write 
all of the PCM protocol interactions to disk. By selecting this option, 
you are able to create the file name in which your data is written.

Some other options exist under the *Send Command* utility. Here, you 
can issue a command to *Clear DTC's* - which will erase any Diagnostic 
Trouble Codes in your PCM, or you can select the *Dump Memory* command, 
which will allow you to see (and store, if you have logging enabled) 
the memory contents of the PCM. In addition, you have the option of 
sending a Custom Command. You'll need a translation document to tell 
you (1) what command to send, and (2) what the results of that query 
mean. These translation documents are floating around the web, you just 
have to find the right person to supply you with one.

The last option is the ability to monitor specific memory locations in 
the PCM. Again, not for the amateur - but very useful to the tuner. 
Once again, proper translation documents are a requirement here, so 
that you know what you're looking at.

When you're through having fun (or have driven your car out of gas), 
you can select the *Action* *Disconnect* to stop your PC from querying 
the PCM, and *File* *Exit* will exit the program. The PCM is always 
transmitting something... Are you listening?

Have fun, good luck, may the bits be with you...