SPN 521 FMI 2

I have a 2015 International Prostar with a ISX and an autoshifter trans. It also has a wingman collision mitigation system, I say all the above because I have been unable to resolve the above code. The engine light comes on when the Brake pedal is depressed and then released whether the park brakes are set or not. I have checked all the wiring, connectors, bulkheads, rebuilt the taillights and wiring and replaced the brake light switch. The trouble shooting guide states the pedal position switch is the fault. If there is a second switch could some one tell me where it is located.
Thank you in advance for all your help and advise.

 

Thanks will check that out.

 

Is Heavyd around and how do I get his attention for this issue.

 

It is not the switch purchased it from the international dealer via the vin. Have checked the wires and connectors even changed the pressure sensor which made it worse.

 

Heavyd do you know how to calibrate the brake sensors?? I was told when installing the new sensor one must do a series of thing ie; step on brake and release park brake with key on or something like that. Any truth to that??
Any guidance would be helpful.