ok, i was sort of driving my car a little harder than usual last night and everything was fine, i even let it cool off for like an hour and a half. but at the end of the night when i was driving home, my check engine light came on, but it only blinked once. i have a 99 civic hatch DX with the stock motor in it. i know i have a small leak in my exhaust manifold but i have a header on the way. does anyone know what it could be?? or is it the leak in the manifold???????

 

It's possible I guess. Does it only blink once when you turn your ignition? Long blink or short blink? It may be giving your sensor thats on your header a funky reading and making your ECU throw that code. Count the number of blinks and remember, a long blink = 10, short blink = 1, I think. Get the code and reply.

 

I think the blinks u have to count to get the codes are the ones on the ECU.

 

when it blinked once, were you jumping the ecu wire, or did it just blink out of nowhere...

if you were jumping the ecu wire, than 1 long blink would be cel code 10 - "intake air temperature" ; 1 short blink would be cel code 1 - "oxygen content"..