Flashing Check Engine then shut off

5053 Views 11 Replies 5 Participants Last post by 2.5x_sleeper, Feb 28, 2014

little_red_foz

Discussion Starter · Feb 18, 2014 (Edited)

Hey forester peeps!

So, this is my first post on this forum, but not new to Subarus.

My mom owns an auto 2000 Forester S. She was driving yesterday and said that the check engine like began to flash, and as she was making a u-turn to come home (she had just left our house, maybe a mile or 2 away) the car shut off. We flat bed it home, and try to see what's going on.

Troubleshooting:
We crank it over, and nothing. Dad checks for spark, no spark. We unplugged the battery cable to maybe see if that did anything. Nope. I tried to read codes with a pocket scan, but scanner said no link. Very odd.

I haven't really got into too much, just doing some research.

I've seen that it could be a bad ground, possible bad coil pack, or the dreaded costly fried ECU.

I will greatly appreciate any info, links, suggestions, anything to help get the process of elimination rolling

EDIT: Car is bone stock. Zero mods.

Thanks in advance!
little_red_foz

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2.5x_sleeper

· #2 · Feb 18, 2014

Welcome to the forum from Oregon! :biggrin:

How many miles on your Forester & is the Subaru recommended maintenance up to date, especially the critical timing belt + associated parts maintenance?

Is there a CEL, if so, what's the code?

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]

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little_red_foz

Discussion Starter · #3 · Feb 18, 2014

There was no code. The code scanner wasn't able to get a link to read, and the CEL is not currently on when the key is on. I've heard and seen what happens when timing belt blows up, and this doesn't sound or look like that. But it's one thing I will be checking.

We recently purchased the car in August and only have to go by what previous owner said. 178k on the clock

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Blue Fox

· #4 · Feb 18, 2014

A check engine light that flashes usually means that potential damage is occurring to the engine at that very moment (bad misfires, bad detonation, etc.).

Now, if you are saying that when you go to turn on the car, and the check engine light no longer lights up, you need to check the main fuses (breakers) in the engine compartment that supply the ECU with power. The check engine light not coming on when you key on the car means it's not getting power. I'm not sure about the older Forester's, but in the engine bay, there are large square fuses with "windows" on the top. They're a pink color. There are some for the ECU, (usually two of them). Check those.

If one of those is blown, you found the issue as to why the ECU is not getting power, and why the car shut off, but not why the check engine light originally came on. Replace the fuses, but don't start the car. Get the car to to the on position and see if you can read a code. There might be a short somewhere that you need to address or you will keep blowing the fuses.

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Sackett

· #5 · Feb 18, 2014

ok, by unplugging the battery you lost the codes.
A flashing cel, 99.9 percent of the time is a misfire; bad enough to possibly cause damage to the cat converter.
I would unplug the spark plug wires from the coil and look at them. Are any burned up or corroded?
My next thought would be to try a new coil on it.

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Blue Fox

· #6 · Feb 19, 2014

Sackett said:
ok, by unplugging the battery you lost the codes.
A flashing cel, 99.9 percent of the time is a misfire; bad enough to possibly cause damage to the cat converter.
I would unplug the spark plug wires from the coil and look at them. Are any burned up or corroded?
My next thought would be to try a new coil on it.

All that is pointless unless the ECU is getting power. If the check engine light doesn't come on the dashboard when you key on the car, it's not getting power......meaning NOTHING will work.

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Sackett

· #7 · Feb 19, 2014

Blue Fox said:
All that is pointless unless the ECU is getting power. If the check engine light doesn't come on the dashboard when you key on the car, it's not getting power......meaning NOTHING will work.

Agreed; but nowhere did he state the cel wasn't on during key on, he stated the light flashed then he unplugged the battery.
Difficult to diag over the net; I would be checking for signal to the coil, As far as no signal from the ecu to hook up a scanner, I have seen that on several scanners where try one it doesn't see it but try at again and it does- so he needs to see if the obd link is powered..

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Blue Fox

· #8 · Feb 19, 2014

Sackett said:
Agreed; but nowhere did he state the cel wasn't on during key on, he stated the light flashed then he unplugged the battery.
Difficult to diag over the net; I would be checking for signal to the coil, As far as no signal from the ecu to hook up a scanner, I have seen that on several scanners where try one it doesn't see it but try at again and it does- so he needs to see if the obd link is powered..

He did.....

little_red_foz said:
There was no code. The code scanner wasn't able to get a link to read, and the CEL is not currently on when the key is on. I've heard and seen what happens when timing belt blows up, and this doesn't sound or look like that. But it's one thing I will be checking.

If no CEL when you key on the car, the ECU isn't getting power, so that means absolutely nothing will work.

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Sackett

· #9 · Feb 19, 2014

good catch, didnt see the second post was reading into the first one trying to get all the details..
The strange part is it flashing first-- Start by checking all fuses and start reading the ecm input and outputs

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debbid

· #10 · Feb 19, 2014

Now, I'm not saying this what happened with your car, but when this happened to my WRX, the mass air flow sensor had failed. My car was still under warranty, so the dealer put in a new one and it worked normally again.

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little_red_foz

Discussion Starter · #11 · Feb 28, 2014

UPDATE:

So, had a friend of mine take a look at it and he started in on the work. First replaced the fuel pump. it ran for a bit, then shut off again. As he tells it (wasn't with him at the time) he was in the car and heard a loud pop. Well turns out it was the coil pack. The coil pack blew up. Left a good char mark on the intake manifold. Replaced the coil, runs good as new, now. What threw me off was that the prongs on the coil did not have any corrosion or anything. So moral of the story, if you have this problem, check the coil pack. My guess is the CEL was from a quick instant of misfire due to coil pack failure.

Thanks for the help guys!
Happy Subaru'ing!

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2.5x_sleeper

· #12 · Feb 28, 2014

Thanks for updating your post!

It looks like Steve, Sackett here on the fourm, was pretty close with his analysis on post #5. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]

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