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Check engine light flashing
Posted: Sun Feb 07, 2016 3:38 am
by ffprz
I hope I'm placing this in the right place but if not let me know. I just recently replaced my heater core. I put the dash back together and reconnected all connections. I started the car so I could burp the system. Once all the air was out I jumped in the car to go get it inspected. I noticed the "check engine" light was flashing. No mechanic had a scanner that connected to this car (94 legacy L FWD MT). Then the temp gauge stated that it was overheating. The needle drops really quick after only a few minutes. I did some research and think the car is on test mode. I made sure the green and black connections were not connected. Then I drove it around but the light did not go away! The temp needle went to the H and after costing in N the gauge went back to normal before I got home. I am not sure what the connections look like but I will include some pictures to give you a better idea. At this point I am clueless!

I need this car running ASAP because its my daily driver. Please help and thanks in advance.

Re: Check engine light flashing
Posted: Sun Feb 07, 2016 4:58 am
by mike-tracy
On your second picture, the black connectors on the far left is the Black test leads and should be disconnected. I'm not sure what the blue colored plugs are, but they should be connected.
Sounds like you still have some air in the system. I like to open the bleeder screw on the opposite side of the radiator when topping off through the radiator cap. These cars are harder than usual to get all the air out.
Lastly, the constant blinking of the CEL is saying you have no codes! Some positive news

Re: Check engine light flashing
Posted: Sun Feb 07, 2016 5:22 am
by ffprz
mike-tracy wrote:On your second picture, the black connectors on the far left is the Black test leads and should be disconnected. I'm not sure what the blue colored plugs are, but they should be connected.
Sounds like you still have some air in the system. I like to open the bleeder screw on the opposite side of the radiator when topping off through the radiator cap. These cars are harder than usual to get all the air out.
Lastly, the constant blinking of the CEL is saying you have no codes! Some positive news

Is it the one in the red or blue circle. As far as the air in the system I kept topping off the radiator until the coolant came out of the bleeder screw without any bubble. Could I be doing it wrong or did I not wait enough for the air to come out?

Re: Check engine light flashing
Posted: Sun Feb 07, 2016 5:55 am
by mike-tracy
Red.
You did right with bleeding, but when the system heated up and opened the thermostat, it freed up a huge pocket of air that had been trapped.
Re: Check engine light flashing
Posted: Sun Feb 07, 2016 8:48 pm
by ffprz
Ok I have them both disconnect. I drove it around for 15 minutes and turned it off any on 10 times. It's still flashing the check engine light. I have no clue on how else I can turn it off
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Re: Check engine light flashing
Posted: Sun Feb 07, 2016 10:26 pm
by mike-tracy
There are two black connectors under the dash. One stays connected permanently and the other is the test connector. I may have misidentified yours. I'll get a pic and post it up. Apologies.
How's the overheating situation?
Re: Check engine light flashing
Posted: Sun Feb 07, 2016 10:30 pm
by ffprz
It's ok thank you for the help. I haven't tried to address the over heating issue yet. I only had time for this one today. When I disconnected the black wire I notice it no longer beeped when the key is in the ignition.
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Re: Check engine light flashing
Posted: Tue Feb 09, 2016 3:53 pm
by ffprz
Ok I finally found the connector. It was behind the harness that I took a picture of. It was a black T connector with a single black wire and if I remember correctly it had a red stripe on it. Now I just have to solve my over heating issue. I also notice when I had the heater on I keep hearing a noise underneath the dash every now and then when I step on the gas. When the car is getting hotter I coast in N and let it idle (going down a hill or down an exit ramp) and the temp returns back to normal.
Re: Check engine light flashing
Posted: Mon Feb 15, 2016 6:39 pm
by Legacy777
Did you plug in the two wire black T connector and the blue connector? The blue connector is a ground.
Regarding the overheating, you didn't clarify but did you remove the bleeder screw on the passenger side of the radiator to burp the air from the system?
Did you replace the thermostat when you replaced the heater core? If so, did you use an aftermarket or OEM Subaru t-stat?