Subaru Forester Blinking Check Engine Light Rapidly

SO here’s something goofy…

A couple weeks ago I was cleaning my car, on the passenger side, beneath the dash I saw to wires hanging with green connectors on them. They were obviously made for each other, male and female. I thought hmm, this shouldn’t be unconnected right? So I connected them, that was a mistake.

The next day I turned my car on and the check engine light was blinking quickly and I thought wow, now what’s the problem. I just hit 1,000 miles on my car so I couldn’t figure out what could possibly be wrong.

I called the dealership to set up maintenance appointment and told them what I did and the problem. They set me up with the appt and I figured that was that.

Being the resource guy that I am I did some searching and found that they’re actually supposed to be unconnected.

I found the cause and what they’re for on the Subaru Legacy Forums actually. The plugs are for a few thing like re-flashing the computer.


So I went and unplugged them and the light stopped flashing.

I called to tell them I fixed it and cancel my service appointment and I ended up speaking to another tech. I explained it to him and he said yes that’s common and he didn’t know why the other tech didn’t know this or why he made an appointment for me foe something so trivial..


Live and learn I guess…

At this point I jammed the wires back up into the console, never to be seen again.

  9 comments for “Subaru Forester Blinking Check Engine Light Rapidly

  1. Bill
    September 15, 2011 at 7:35 pm

    Thanks for the information. I plugged them in this evening when running satellite radio antenna. After noticing the quick flashing, if thought it was the fact I connected the green connectors. I disconnected with the car was still running and nothing happened. Then did a google for this issue, found your post and unplugged and turned the car on. No flashing CEL.

  2. Kryn
    June 1, 2012 at 2:15 pm

    Wow. you saved me hundreds of dollars once I found this article!!! I went to oreilys auto parts, guy there did a diagnostic test, 11 codes showed up and obviously I need to give my subi some love! But, he saw that those two green wires “needed to be reconnected” luckily he told me that he reconnected them for me as a favor! I drove 15 miles, with my check engine light flashing rapidly! called all sorts of mechanics and looked up parts.. finding out I was about to spend over a grand on new parts. Fortunatly, I saw this.. unplugged those wires and now my CEL is no longer flashing!!!! THANK YOU for the HELP!!!

  3. Oz99forester
    September 20, 2015 at 12:04 am

    99 Forester, 231k miles, blinking CEL problem. If your car is not smoking, it’s probably not a bad cylinder or valve issue. It’s probably a missfre condition. And hope you have been changing that oil.

    Check your coil and plug wires, so they aren’t arching somewhere. In my case they are new, check your plugs, if you see oil on them, you may have a seal issue, it will affect your spark and your engine can run rough.

    Make sure you don’t put anti-seize on the plugs, or very little, you should be changing them every couple of years anyway, they don’t ground right with too much of the compound.

    My mechanic checked my # 1 cylinder for spark when I had a timing issue, my tensioner got weak and my belt skipped a tooth, “really rare”.

    He then put the plug back with too much anti-seize. It affected the ground the plug makes to the block, ie, misfire cylinder 1.

    The car was running really rough, it felt like only 3 cylinders were firing, it didn’t stall but had weak response and shook like my engine mount was bad.. It wasn’t… I thought it might be an injector but it wasn’t.

    The CEL flashed fast… I wasn’t able to read a code..

    The code didn’t come up until I shut the car off and then re-read it again with the scanner when it wasn’t flashing yet… P0301 Cylinder 1 misfire.

    I took the plug out to check for spark, it was good, but I found a glob of silver anti-seize on it. Cleaned it off with a rag and then a small brass brush…

    So… annoying… come back from my mechanic, fix one problem and then have other issues….

    After I cleaned the plug. Checked all the connections. Erased the codes by disconnecting the negative terminal… Put it all back and rechecked every connection… Started right up… Got my power back… instantly!

    Hope to hit 300k with this Forester, it still gets 24plus mpg combined average

    Good luck, hope this helps with your old Forester.

  4. Aarón Falomir
    September 14, 2016 at 12:41 am

    Kristofer! I am really grateful.
    Today I had dynamat applied to my 2010 subaru forester , apparently the guys that installed it also tought on joining the green connectors.
    Another side effect is: when I opened the switch the fan will go on and off with the relay sound.
    After reading your text I saw those green connectors and I unplugged them, the engine light stopped flashing and the fan stayed off with the switch open.
    Really, thank you for this post!
    I will send you a tequila bottle! Regards from Mexico.

  5. Carol Stanley
    October 26, 2017 at 12:36 pm

    Wow, I saw this post today and disconnected the green plug and the check engine light stopped flashing/fan stopped running. So awesome, thanking all the awesome car guys who post this information!

  6. ben
    December 2, 2017 at 3:25 am

    awsome info just prevented a heart attack for me. thank you thank you

  7. Fiorella Huhn
    March 23, 2018 at 4:13 pm

    2011 Subaru Forester
    Took our car for a minor collision damage on the driver side. Picked it up check engine light flashing rapidly. Read your blog and problem fixed. The mechanic that worked on our car thought he had disconnected those two green wires. So he connected them. We unplugged them and voila. Thank your for posting this.

  8. M Blascetta
    June 24, 2018 at 8:33 pm

    Whew – I thought I was the only one…I did the same, was cleaning out my 2011 Subaru and saw the two green connectors, male/female, connected them thinking maybe the grocery bags or my briefcase from work had separated them….when shortly thereafter, driving home, the check engine light started flashing and I thought WTF…….I went through this with my 1995 F150 and knew gas cap was one possible cause – checked it and nope that wasn’t the problem and next was the CC which would be serious coin…then I went to the internet and fount your article, went out, disconnected them, and done. Thanks for your post….

  9. Nick Salmon
    July 24, 2018 at 7:30 pm

    Just got my car from the shop everything was fine. I opened the passenger side door and saw two unconnected green wires – thinking I was just fixing what could be a problem later I connected them. Drove the car into the garage and it was blinking like crazy. Not thinking either was related I googled rapidly blinking check engine light Subaru forester. Your article was the first hit. You just saved me a ton of time and a ton of yelling. Thanks!

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