Hi,
I really don't want to see the check light in my life, but I see the check light these days, when I start engine in the morning.
The check light only came on at cold condition engine 5sec after started the engine and never go away.

I went to Honda dealer to check it with scanner, it was O2sensor feedback problem at first time. Next morning, the check light came on again, and it was different code which was Air/Fuel ratio problem.

An honda engineer said it could be throttle body or sensors around it.

I've check the fuel cap, nothing wrong with it.

Anyone can help me this?

 

you are talking about the actual check engine light right? not the maint reqd light, right?

you need to pull the code, and then post it here. without that, we can't help you.

 

I can't remember the code at first time, I think it was P0172(Fuel sys. too rich). The enginner said it was O2sensor feedback problem.

After reset, I got P0411 CEL.

I've checked the vacuum lines and everything is fine.

I will ask the exact code and let you know.

 

I see the code which is p0411 CEL first, and I think air pump only works at cold start, but p1411 came on when I accelerate the pedal at the scanner.
Plz help!!!

 

I've found something strange. If I push the accelerator even once a little when I start engine in the morning after reset the backup fuse, the check light would not coming on.
HELP~~

 

P0411 is a air pump code .

The last car that I worked on with this code had a pinched pump line .

Things to check ,

Does the airpump turn on when you first start the car ? It is located in the drivers side front bumper.

If not check for a bad fuse.

check vacuum lines to the Airpump relay for holes or if it is being pinched . Or bad relay

Lines feeding the air pump from the intake . And line coming from the airpump to the EGR . look for pinches or leaks.

Bad EGR

The po172 code could also be caused by this .

The airpump on startup pumps air into the exhaust in causing a lean condition in the exhaust stream to warm up the catalytic converter to operating temp .

So if it was not pumping air in to the exhaust the O2 would read it as rich .

The dealer could have checked the sensors with the scan tool . It does more than just read codes . You can plot both O2 sensors to see if they are work properly . They could also make sure the values of the TPS and MAP are correct . Even though I don't think the throttle body sensor have anything to do with your problem .

I would say its one of two things .

Something related to the airpump , Being its bad , fuse , vacuum , switch or input or output line between the intake, pump and EGR

Or a bad O2 sensor which can be easily diagnosed with a scan tool reading the O2 . Not the codes but the sinewave .