The Y body pcm has always had a different service number than the F & B bodies.
is there a physical difference besides the number?
can the F/B body PCM be flashed to a Y body calibration and run a Y body with no issues?
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The Y body pcm has always had a different service number than the F & B bodies.
is there a physical difference besides the number?
can the F/B body PCM be flashed to a Y body calibration and run a Y body with no issues?
There are some extra chips added. One for the rear 02s, which are not used in the code anyway, and some obd2 vpw chip that can communicate over obd2 device.
Both of this are not needed for engine operation, so my guess is it should work.
I had wondered about the dual knock sensors on the Y bodies and if they're both utilized in the code.
The 2 knock sensors are wired in parallel to pin d22. So the knock module might be a different part number. Someone can check the p/n to verify. I also traced an unused pin d13 that goes to knock module. It could be left on the the board and have been developed for true dual knock sensors but never implemented.
I have never verified the knock module part number, but have flashed F-body pcm's and used them in Y-bodies before with no issues. I've even used F-body OBD1 Pcm's in an OBD2 Y-body using an OBD1 Y-body definition file. Only had to change the knock sensors on the engine if I recall correctly.
The earlier PCMs use a resistor present inside the knock sensor to detect if the sensor is present and connected. I believe this is done using the DC bias of the sensor. Essentially the bias is a voltage generated in the PCM and a series resistor. This bias resistor and the resistor in the sensor form a voltage divider that is measured on the PCM. Should the DC voltage at the terminal be too high, the resistor in the sensor has been disconnected and this generates the fault. Too low a voltage indicates a short to ground.
The later system uses AC to detect connection to the sensor. This is a far more reliable way to go. When the engine is running the vibrations are converted to a signal by the knock sensor. The signal is then processed and tested against two configuration parameters. Too much noise or too little noise produces fault P0332 indicating knock sensor or knock module fault.
To sum up, most of the circuits are exactly the same between early and late PCMs. The knock module and knock sensor along with the software must all be from the same generation. There is probably a way to use various combinations using custom software but it's not worth the time/effort.
-Tom