Got a good diagnostic light show on the dash. What's it mean?

[Crunch]

I was trying to check engine hours the other day and must have off-timed the hand operations. All the lights on the dash came on, and both the speedometer and tach ratcheted up, then down. After that, the odometer when through the cycle to show C codes. There were no C codes, and visually this was pretty cool. What's the purpose of this diagnostic, and what are C codes? I've never had any experience with them.

 

[p-Bar]

Yes I done that before, can't remember how. I think it's just the diagnostic for the instrument panel.

 

[Wayne M.]

If you hold the button and then key on, you’ll walk the panel. Most newer vehicles do this, and aside from it being a function test, I know of no other purpose.