First: You haven't used code tags, please edit your post and include code tags to make the post readable.
The code you posted is a class library, not a sketch. The library was written for a pre-1.0 IDE version and won't compile as-is on a current IDE. I'm not surprised that a library for itself won't display anything on an LCD, especially if the library doesn't include any LCD code.
To give you a start: http://www.openhardwarehub.com/projects/40-Arduino-CAN-BUS-OBD-Gas-Gauge this is a project, that does use more or less the same hardware components although arranged differently. Nevertheless you should be able to use some of the code.