Dante(suzuka)

Last December I had a recurring problem with the Secondary Air Injection system, part of the O2 and Emissions systems if I recall. CEL codes 0410, 0411 to be exact. The car drove fine but it would give me these CEL codes on very cold starts and occasionally stall. The Honda dealership ran all the tests, never found a problem, and installed a new O2 system, and finally ECU.

Two days ago I had the same problem again. Quite frustrated I took it back to Honda and they ran the usual tests without finding anything. Then the Service Manager called Honda Tech Support and convinced them to look farther into it. They eventually tracked it down to a bad rely or voltage regulator(I forget which) that was failing to activate the emissions system on those very cold starts. They are replacing that today with a new part. APparently this info wasn't available last year.

The moral of the story is that if anyone else is having a similar problem, go to Honda and ask about it, they might know a little more now than they did before. I might be the only single person with that problem, but I doubt it.

CN: 0410, 0411 Check Engine Light codes might be caused by bad wiring.

PilotKD

This sounds similar to what I have been recently getting with my '04, but with no check engine light. I'm assuming the Secondary Air Injection System is designed to inject extra O2 into the engine on cold starts to reduce cold start emissions?

Slows2k

A malfuntioning secondary air injection system won't cause the engine to run rough or stall. The convertor won't warm up as fast as it should, and the CEL will come on. It won't cause a stall at cold start.

If it did, everyone who has screwed up the vacuum lines (many people) when installing a CAI would have the same issue.

xviper

I think the stalling is simply coincidental with your CEL. As Slow just said, the issues that activate those codes won't cause the engine to run much different.
I believe that this is a time of year that many S2000 owners experience this stall after a cold start. This is the time of year that many of us see climatic changes that have a way of causing the ECU to have a "brain fart". If I'm right, this condition will correct itself as the ECU "learns" over the next 4 to 5 cold start stalls.

Dante(suzuka)

I see, and that makes sense.

I was not getting a rough start normally when this happened. It was just the CEL code. Maybe I'm the only one then? Very rare.