GC8 ecu reset (proper way!)
 

Classic (GC8 - JECS) ECU Reset

1.Ensure engine is at normal operating temperature, turn engine off
2.Locate the two ECU connectors, located under the steering column and consist of a black plastic male and female connector, and a green male female connector

[IMG]http://www.scoobypedia.co.uk/uploads/Knowledge/classic_test_mode_connector.gif[/IMG]

3.With the ignition OFF connect black to black and green to green.
4.Turn on ignition, do not start the engine, depress the accelerator pedal to full throttle, then return it to the half-throttle position and hold for a few seconds, and then release
(Engine Check lamp turns on).
5.Start engine and then [B]drive for at least one minute, keeping road speed above 11 Km/h. [/B]

At this point the check engine light should start to flash the all clear signal (steady 1/2 second interval flashes). If the check engine light does not flash, or indicates some other sequence, there is a fault present in the system (this post tells you how to read the codes: [URL="http://www.perth-wrx.com/vb/showthread.php?p=406615#post406615"]http://www.perth-wrx.com/vb/showthread.php?p=406615#post406615[/URL] )

6.Stop the car and turn off the engine.
7.Disconnect the black and green connectors.
8.Job complete - ECU is now re-set.

Apart from your other post about about the ECU re-learning the ignition timing, what does resetting the ECU achieve?

Resetting the ECU clears all stored codes and puts it into a full diagnostic cycle to check if any new codes will pop up.

As the Subaru Ecu's are self learning (to varying degrees), it also clears any stored 'bad habits' learned & stored by the ecu.

Such as running regular unleaded or getting a bad batch of fuel, which may cause the ecu to permanently pull some ignition timing.

aaah that sounds good. So it would be worth doing this plus the quick re-learn at every service, or only if it feels a bit sluggish?

I used to do it every oil change, just as part of doing the job.

What about for a flashed ecu, like ecutek or something like that Ross? Would it be affected by this?

No it won't change the tune Alex.....

Mrt says it's a o.k. and that a bad batch of fuel / running regular ulp WILL have the ecu running minimum 'happy factor' (minimum timing) in the case of Ecutek.

Cheers for the info, im nearly due for another service so ill give it a shot :D

is it worth doing a a RX.?

probably not.

It was worth doing it on my GX when it was auto, as it reset the auto TCU as well. Then it learnt all my bad driving habits

chirp 2nd? :D

Rossco is a legend :)
cheers dude

cheers for this, just what i needed. thanks.

I'm a little lost with this ECU re-set business
 

It might initially seem odd that some dude from the west coast of Canada is seeking information on his JDM vehicle here on an Aussie forum... but it'll hopefully make sense why I am doing so.

JDM vehicles are rather rare in Canada, and they're even more rare in the States (due to their more restrictive import laws). I'm often frustrated that I can't find the info I want on North American Subie forums. And I can't speak Japanese, so that effectively rules out forums in Japan. ;) I believe there's some sort of familiarity with JDM vehicles Down Under, so here I am.

And here's my problem...

I've read and re-read this thread as well as its companion thread -
[URL="http://www.perth-wrx.com/vb/stock-ecu-discussion/30024-how-read-subaru-cel-gc8-stock-engine-control-unit-only.html"]How to read Subaru CEL (GC8 stock ecu only)[/URL] When I connect the black connectors and turn the ignition key to ON, there are [I]no[/I] signs of the diagnostic mode... no relays clicking, no fans running. However, I get a code 24 flashing (Idle air control solenoid) which is rather odd as the car doesn't appear to exhibit any idle speed issues.

I wanted to clear the code, so I went through the process of connecting the green connectors with each other, as well as connecting the black ones. [I]That[/I] produced all the clicks and whirs which I was expecting to witness in the previous process. Anyway, I also went through the other steps with the gas pedal. After I started the engine and drove for a couple of minutes, instead of the CEL flashing the all clear signal, I got a code 32 (Oxygen sensor). :confused:

That was odd, but I thought that if I then connected just the black connectors, that it would now indicate this "new" code 32. But no, it instead displayed the "old" code 24... which was supposed to have been re-set by the previous green-green and black-black process.

What is going on? What am I missing? Have pity and help a poor confused Canuck out, eh! :rolleyes:

Issue has never been resolved
 

If someone stumbles across this thread, I'd still appreciate any knowledge that could be shared regarding my ECU questions above.

[QUOTE=Vancouver98STi;849147]If someone stumbles across this thread, I'd still appreciate any knowledge that could be shared regarding my ECU questions above.[/QUOTE]Im in the same boat. Car started misfiring and cel come on so put it into diagnostic mode which gave me the knock code. Swapped spark plugs and have started putting 98 into it. Now that i havent had any issue with it i would like to clear that. Went through the steps and come to the same conclusion. Code 32. Oxygen sensor and the ecu wont reset.

[QUOTE=kingslayer567;850976]

Im in the same boat...[/QUOTE]
I posted about this issue in [I]several[/I] Subaru forums around the planet... and never got one single response. :confused: It was like I was asking about some taboo subject.

I eventually just disconnected the battery, stepped on the brake pedal (to discharge capacitors in the ECU), and carried on. Seems to do the trick.

One other tip to add, regarding the ECU re-learning idle speed control after disconnecting the battery.

[quote=GrundleJuice]

After resetting the ECU, turn key to on/run for 20 seconds then back to off. Then start it and allow it to idle for 8-10 mins without touching the accel pedal or putting any significant load on it like a/c, head lights, power windows or even changing manifold pressure by applying the brakes. When engine speeds are rapidly falling toward idle, like when depressing the clutch after decelerating in gear, the ECU has to signal the injectors to inject fuel to "catch" it before it gets all the way to idle speed. I assume this is a learned part of the ECU logic since it gets better after some time. If you have an aftermarket or modified intake it may take longer or be impossible to get perfect. Anytime you disconnect the battery it resets the ECU and therefore clears any codes. If you want to find out what DTC was triggering a CEL you should not reset the ECU first.[/quote]