The speedometer would read normally, but I would get the CEL P0500, computer went into limp mode, and I had funky idle/stalling issues.
Here's how it works: The signal goes from the speed censor to the speedo head in the gauge cluster. This does two things, shows your speed, and sends a different signal to the computer.
The problem: The signal isn't making it to the computer, which I confirmed with my OBD2 scan tool.
The solution: The speedo head is held into the gauge cluster with 4 screws. They also transmit the signal from the back PCB to the speedo head. The screws can back loose and cause this CEL. Simply tighten the screws up, and you're all set! A picture speaks a thousand words, the screws in question are circled in red.
Edited by 987687, 27 January 2011 - 12:44 AM.