I just bought a 2003 Mack CX 613 with a 427 horse E7 with 507k miles. Is there any way to read fault codes without the scanner? I ask this because someone told me you can manipulate certain speed and other settings in the computer by pressing a certain combination of buttons on the dash and somehow entering the last so many numbers of the VIN. Could this be true?
We put a computer on it at the dealership that sold it to me (6 hours away from me now) and it showed a code that said "engine position sensor-erratic idle" We swapped in a new sensor and the problem went away for about the first 3 hours of driving then it came back. What's happening is when hot, it idles smoothly for about 3 seconds then I get a split second "upward" surge where it jumps up about a hundred RPM. About evdry three seconds or so I get that slight upward jump in the RPM. Also, my driver reported an occasional check engine light on his 380 mile loaded trip yesterday but I have yet to see a CEL when I've drove it about 6 hours with no trailer.
I've tried googling for a self test function in these engines but I can't find anything.