Hello again Car Talkers. I have had this issue before but with different circumstances and I’m hoping once again that one of y’all can clarify it for me.
09 Hyundai Accent with a bit over 24K miles on her.
I started her up this morning and the engine shook a bit and the CEL flashed about 5 or 6 times but did not stay illuminated. It drove normally and sounded normal. Subsequent starts were fine, the CEL didn’t flash (nor did it come on) and it drove fine. Is this just something random or is this something I should have checked? I am road tripping this weekend so I’d like some peace of mind. Thanks for any assistance you may provide.
It is a problem, and a fairly serious one at that. A flashing check engine light means that one or more cylinders are misfiring. This means that raw gasoline can make it to the catalytic converters and damage them. Since it should still be under warranty, you should take it to your dealer as soon as possible to have them diagnose the problem. Even though the light is off now, the problem codes should still be stored in the PCM.
Don’t take my word for any of this. Open the glove box and get your owner’s manual out. It will say that when the check engine light comes on, you should take it in for service when it is convenient. It will also say that if the check engine light flashes, the only place you should drive it is straight to the nearest service center.
Yes the flashing light isn’t your favorite thing. It usually means that there was a misfire while the light was flashing. When the misfire stops, so does the flashing. That is not the worst thing.
The worst thing is that the light COULD start flashing and not stop. If that happens you could damage the catalytic converter and that will cost you at least $400, possibly $1200.
If you keep driving with the flashing light, an image of Dirty Harry will appear and ask you if you feel lucky. Five minutes after that an image of a mechanic will appear and tell you that you made his day.
You are under warranty I would ask the dealer for their opinion. They likely are slow right now so they can at least check if you have the time to get into their shop.
I have actually made an appointment for Thursday. In the meantime I did take it to a local chain shop and they scanned it for me and it came out as p304, which is a misfire according to the guy who helped me. He suggested I take it back to where I just had the spark plugs changed last month and have them check it, as it could have been something as simple as they installed the wrong kind of spark plugs. He also said it could be something wrong with one of the coils (looked fine according to the invoice I received from the spark plug change) or I believe the catalyctic converter as mentioned in above posts. I am going to take it back tomorrow to the spark plug changers (as long as they’re open-that’s where I was going to start anyway) and have made an appointment for Thursday with the dealer if it can’t be resolved otherwise.
Yes, P0304 is a cylinder 4 misfire. Why were the spark plugs changed? It seems to me that it is a little early given an '09 car with 24K on it.
Unless the car has been abused, given the recent work a spark problem would be the most likely suspect and a trip back to the shop that did them would be the first order of business. Some cars are picky about spark plugs and perhaps they installed something other than an OEM equivalent. It could also be as simple as someone having not gotten the plug wire fully seated back onto the plug, or even damaged the wires on R&R. Checking all of that out is certainly the first step.
I changed them cuz the manual said to. What is R&R? Repair/Replace?
R&R is just remove & reinstall/relace. The wire gets pulled off the old plug, then reinstalled. It can be damaged on removal, or improperly seated on replacement.