I am currently developing an application which retrieves diagnostic trouble codes from my car's OBD system and display any DTCs in a list.
However, as my car has no trouble codes I am unable to test the functionality of this application. I am using mode 03 of the OBD-II standard SAE J1979 to retrieve the trouble codes using AT commands, an ELM327 Bluetooth Dongle and a Nexus 7 (2012) tablet. While I know that this functionality works in theory, I would also like to test that it works in practice, so that the application can be developed further down the line.
I was reading that the 'Check Engine' light on my car could be activated by leaving the fuel cap off the gas tank - solely for testing purposes. My car is a 2005 Ford Fiesta Mk6.
My question is whether doing so could cause any damage to the fuel pump due to reduction in pressure for its required operation and if so, would testing of this kind be worth pursing?