Check engine code

"BK" wrote in news:r2Ozg.5$ snipped-for-privacy@fe04.lga:

In plain English, your engine has a special door inside each manifold runner (there are four) that restricts the amount of air entering the cylinder. Above 5,000 RPM, these doors open, admitting more air. Your engine computer has decided that something has gone wrong with the IMRC system, and has illuminated the MIL.

That the error code starts with "P1" rather than "P0" means the code is a voluntary code that Honda put there without a diktat from the EPA. Honda included it as a diagnostics tool.

A P1078 error can be set by a number of things that control the IMRC system, anything from an IMRC valve that won't hold vacuum to a failed electrical component. And if the history of such things holds here, it's entirely possible you're seeing the error on account of something that has nothing at all to do with the IMRC system. This is why the dealer won't tell you anything. They have to snoop around and do some tests before deciding on a culprit.

The correct procedure in such cases is to reset the MIL, then just drive the car as normal. If the light comes on again with the same error, then they get serious about it. A large number of errors are transient and do not recur.