The Z won't rev very high unless the transmission is in gear AND the brake is not applied AND clutch pedal all the way up (if applicable).
I did a Q&D web search for "B18C0 DTC" and didn't see anything.
My guess is that it's either a random glitch that will never happen again or your ECM has a malfunction. Resetting the ECM, as you have already done, is the only thing I can think of to try. Good luck.