The PATS LED is connected to the pcb but is wired directly back to a -5v output from the ECU (pin.42). The board contains no immobiliser functionality.
After checking the wire diagrams, it appears that the ECU pin 42 goes to Dashboard sub hardness connection PCM (pin 5?) cable Y97. Could this be correct?
I have sparse wiring diagram info but with what I do have Y97 looks correct. To verify you should be able to buzz the LED wire all the way back (via Y97) to pin.42 on the ECU.
This is the ECU pin numbers looking at the ECU connector (not the ECU).
