I started my car this morning from the outside by leaning in through the window and turning it on, to let it heat up.

About 20 seconds after, I heard my engine change in sound, similar to how it sounds once heated up, but a bit duller.

I then got in the car and noticed my check engine light was on. The idling of the car felt weirdly soft, but I had no problems driving ~20 miles to work up and down hills. I was sure to keep my engine under 3000 rpm, but didn't feel a big loss of acceleration.

Also my headlights have been flickering occasionally so it might be something alternator related?

Any ideas? Thanks. Will be getting codes read later when I am free.

Car: 2005 Honda Civic 4 door w/ 112k miles

UPDATE It was a P2647 Fault, which I then topped off the oil to fix. I think my oil level was really...really...low.... :(

  • 3
    My idea is to get the code read at a parts store or repair shop. Not much anybody can do before that's done.
    – cory
    Feb 2, 2017 at 15:07
  • Right, but as I am waiting here at work, I can't do that, so I came here to find out if someone experienced this scenario.
    – Prodnegel
    Feb 2, 2017 at 15:14
  • 1
    You really need to read the code! But in my case, I was driving a 2011 Toyota Yaris and I noticed the check engine light was on. No big loss of power. Reading the codes indicated it was the rearmost of the two O2 sensors, and replacing that sensor indeed fixed the problem. The problem didn't occur when the car was idling, so I cannot say whether it would change the idling sound of the engine. Please remember to tell us what the code was after reading it!
    – juhist
    Feb 2, 2017 at 15:21
  • I am thinking it is an alternator issue, as my headlights have been flickering a bit occasionally
    – Prodnegel
    Feb 2, 2017 at 15:25
  • @juhist Help me get out of work early?...lol. Do you reccommend using my own OBD2 Scanner??? Or just taking it into a shop.
    – Prodnegel
    Feb 2, 2017 at 15:26

1 Answer 1


I read the codes last night and it turned out to be a stored P2647 causing engine light. What a dummy I am...because I checked the oil level and it was really low, like below the bottom dot...

Added about 2 quarts of oil to my 1.7L engine...hope that's okay. It drove pretty well to work this morning with no oil sounds or stuttering, but the CEL remains. Hopefully in 3 days it clears, or I'll take it in.

enter image description here


THE CEL IS GONE!!! After work today, the light is gone now! It probably reset so fast due to it being a 1 cycle fault that Ben pointed out in the comments.

  • 1
    I am the author...I read the codes....this is the answer...
    – Prodnegel
    Feb 3, 2017 at 15:36
  • Just reset the code with your code reader. If there were any real issues you'd notice while driving as the i-VTEC system would try to operate above 3000rpm and you'd experience bucking. Also try to find out where that oil is going.
    – Ben
    Feb 3, 2017 at 22:39
  • @Ben, Why would I reset the code? Sure it will come back again if the problem persists (right?), but I was kind of thinking that if I truly fixed it by adding oil, it will dissapear by itself within ~3 driving days.
    – Prodnegel
    Feb 3, 2017 at 23:08
  • 1
    You'd reset the code so you'd have visual feedback on whether the monitor passed or failed without waiting for the number of drive cycles to pass. IIRC 2647 is a 1 trip monitor so you'd know almost immediately if the problem is fixed or not.
    – Ben
    Feb 3, 2017 at 23:11
  • @Ben Thanks! Awesome piece of info right there....hey and guess what, the CEL IS GONE!!!!
    – Prodnegel
    Feb 4, 2017 at 0:15

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