12CT15IS

Hello, we just bought a 2012 CT from “a little old lady” with only 15k miles on it. She drove it about once a week but only a very short distance. This car looks like new. We took it on a 3 hour road trip yesterday and the CEL came on, in addition to a couple rough idle moments.

I scanned it today and it is P0301-cylinder 1 misfire. I’m really hoping it’s not a blown head gasket but it sure fits the symptoms. Is this something that you can imagine happening at only 15k miles? I’m wondering if maybe the gas in the tank went bad and could have gummed up something, so I am going to run some injector cleaner through it. Anything else I should look for? I’ve read about the spark plugs ans injectors but again- at only 15k miles??

I appreciate any input!

JNguyen9

Unlike other cars, low mileage hybrids aren't a good thing. You run into other potential issues like having to replace the hybrid battery. It lasts longer when it's in use. The issue you're describing sounds like the head gasket since cylinder 1 is the usual culprit. Have you checked for any loss of coolant?

12CT15IS

I was initially concerned about the low mileage, but after researching a lot and talking to a couple local hybrid techs I was more comfortable with it. Unless it sat for months unused(which it never did), the battery system should be fine and at the most we would notice a decrease in economy. Even if that happened and we have the hybrid battery replaced we would still be ahead in terms of value considering how much we paid for this.

However, I didn’t expect major engine work. The problem is very intermittent and the CEL hasn’t come back on (yet), so I’m hoping it is EGR related and hasn’t blown the gasket yet. I’m thinking of taking it to a dealership to test for a blown head gasket to hopefully eliminate that cause. We have only put about 400 miles on it since we bought it but I have not noticed a loss of coolant in that time.

JNguyen9

Good to hear it didn't sit for long periods of time. The next thing you could check is the EGR system, which is what you would want to be the cause.

orca4wd

Hello, First incarnation before digging into head gasket is to test coil/spark plug on #1. A suggestion is to pull out #1 spark plug to see if is clean. Also, switch around #1 coil from a different cylinder. If P0301 code show up again in #1 then issue is not the coil? I'm interest to hear what you find out... Good luck!

morganc

Coil is a good start as mentioned, next thing you should do is let the car sit (after a good hot run) for a few days, then stick a bore scope down the plug hole and check for coolant.

You could also have the old style intake manifold , refer to TSB: L-SB-0019-16. Next would be EGR clean (and/or intake manifold EGR ports if you haven't replaced it) but I doubt there's much build up after 15k miles.

Good luck!