2016 Forester 2.5i Premium - My Car Threw Codes - Can I trust It If They Don't Re-appear?

Hi folks,
My Subaru Forester threw codes at me today. There was no unusual behavior leading up to or at the time the warning lights appeared. I got the CEL, the hill start assist light, and the EyeSight and the dual eyesight and collision mitigation warning lights all at once. The infotainment also then says words to the driver that say the same lights are on.

My mechanic put down a sandwich to connect a modern code reader to the car and we found a few codes including “Random Misfire,” “Eyesight 10,” and an ABS code. My mechanic cleared the codes and I went on my way, drove the car for over an hour with multiple restarts. No recurring codes. Zero changes in its driving behavior.

My mechanic said that if the car was running poorly, or if the code had been more specific and instead said something like “Cylinder 4,” he would consider more troubleshooting.

So, as a non-mechanic interested in this subject, can anyone tell me if clearing codes in this fashion and then having them not reappear right way is a sort of glitch or hiccup that may not mean there is a real issue? Or is there a real issue most of the time? The car has been lovingly cared for and has about 28K miles.

Any insight is welcome. I photographed all the codes, the lights, and the results of the code reader if they may help.

Thanks in advance.

Apparently unrelated codes that don’t come back? Sounds like a glitch to me, you’ll learn soon enough!

If the CEL doesn’t re-appear, the problem has gone away. If you had enough drive cycles (5 or so) where the error didn’t occur, the CEL would have gone out by itself. Sometime glitches happen and throw “nuisance” lights. Some times problems occur even on low mile, well maintained cars. As you’ve seen us post… sometimes stuff just breaks!

Your mechanic did the same thing I do if I get a CEL but the car is running OK. See what it is, clear it and drive on. If it comes back, I dig in further.

This is a great example of the value of establishing a relationship with a good independent shop. He does a quick check, clears the code, may not even charge you knowing full well you will return if the CEL comes back.

Thanks folks. I feel better already. Yes, my mechanic has taken time to help me now three times this month without allowing me to pay. A loose wheel ( that a local mobile tire service did not tighten), this code read and clear, and a brake fix that he felt he should have done better the first time. He’s a great guy and a good neighbor.

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Sometimes it just happens. Maybe you got a small contaminate in your fuel that momentarily clogged and injector until the high pressure just blew it through and everything went back to normal. About six months ago, as I was pulling up to the gas pumps, my truck ran rough for a few seconds. I filled up and when I restarted, the check engine light cam e on as the engine stumbled for a second. The it ran fine after that and has ever since. The light never came back. It had a P0307 code that has not come back either.

To me, problems in multiple systems gives suspicion to grounds.
Also make sure battery terminals are clean & battery is healthy.

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Thanks for the suggestion. I checked them today and they look good. I agree it sounds like an electrical issue.

As others suggest, if it doesn’t come back forget it.

Here’s a relevant, even car-related, story from the business I ran before retired (under the name Computer Doctor):

Three employees of a computer company were going to an industry conference. Rented a car at the airport they arrived at. Driving down a steep curvy hill it suddenly spins out 360 and almost throws them over a cliff. Stopped and recovering from the shock, the guy from the Marketing department says “I’m calling the rental agency and making them drive out here with another car for us.” The hardware engineer says, “Wait a minute. Pop open the hood… I’m got my pocket took kit with me… there must be something under there I can find, adjust and fix the problem.”
The software support guy (that would be me) say. “No. Don’t do any of that. Drive it back to the top of the hill and drive down again, and if it doesn’t happen again, forget about it.” :wink: