[ACHAHockey]

These past 2 weeks or so, I have seen a couple posts asking how to reset to ecu. So i thought id make a how to with a few pictures to keep future posts down. Stick worthy?

1.) Make sure your car is off, take the key out of ignition.

2.) Pull hood latch:


3.) Open hood:


4.) Find your battery. Loosen and remove the negative terminal (-) on the battery, its the black one. That little nut on there is what needs to be loosened. I circled it in red:


5.) Pump brake pedal a few times to clear the ecu's memory:


6.) Re-attach the battery terminal, shut hood, and you're all set.

[SENSEIMACK]

thanks, i need to do this because after getting my car tuned and ecu reflashed, my cruise control doesnt work and i called them and they told me to what you just said. Easier now that i have seen pictures.

[300]

Originally Posted by ACHAHockey

These past 2 weeks or so, I have seen a couple posts asking how to reset to ecu. So i thought id make a how to with a few pictures to keep future posts down. Stick worthy?

1.) Make sure your car is off, ...

When I installed my typhoon I just disconnected the battery (-) per the instructions. I dont know if it was meant for resetting ECU or just for safety...Im assuming more for safety. Im goin to be installing my exhaust over the weekend I can reset it then. but what does pumping the brake do? How does it reset the ecu?

[CrystalMeth]

Originally Posted by 300

When I installed my typhoon I just disconnected the battery (-) per the instructions. I dont know if it was meant for resetting ECU or just for safety...Im assuming more for safety. Im goin to be installing my exhaust over the weekend I can reset it then. but what does pumping the brake do? How does it reset the ecu?

Pumping (or holding) the brake drains all the power out of the system so there is no power whatsoever going to the ecu. Therefore it is "wiped".

[DCH]

7.) Wash your car for a job well done



Nice write up!

[BoostnSTI]

funny how simple this is and how there are ppl who are clue less on how to do it. this will definetly help in the future for new members

[V8Huntr]

Originally Posted by DCH

7.) Wash your car for a job well done

Yea that's one dirty front end!

[V8Huntr]

Oh and note, your car will crank a lot longer than normal before it starts. Don't worry if it takes a few cranks, it's normal.

[300]

Originally Posted by V8Huntr

Oh and note, your car will crank a lot longer than normal before it starts. Don't worry if it takes a few cranks, it's normal.

cool..after it goes thru that will the car start normally from there on? Im new to the Sti modding, so Ill be asking alot of questions thanks for the heads up!

[V8Huntr]

Yea just the first time it starts up a little slow. After that initial start it will start up normally. Resetting the ECU clears the learned memory and sets the ECU back to the base MAP. The ECU learns as you drive and adjusts air/fuel, timing, etc based on sensor readings. It stores that learned memory in a temporary memory location within the ECU, kind of like RAM in your computer. Once you take the power source away from your ECU, that memory module clears itself. The base map is written onto a ROM within the ECU and isn't lost when the ECU is reset. Basically, as long as your ECU has power then that learned memory will always be there.

[jungo75]

Originally Posted by DCH

7.) Wash your car for a job well done



Nice write up!

Beat me to it.

[WRX4ME LE 482]

Im not sure how similar the "hard starting" is when resetting the ecu this way to actually flashing a different rom (which also does a reset), but in my experience with flashing different roms sometimes itll be hard to start for a few attempts. It's scary the first time, but after that you realize it's completely normal.

[V8Huntr]

Yea it does the same thing when you flash to stage 2 or any other map. It scared the crap out of me when I put all of my stage 2 stuff on. I thought I broke something!

[300]

Someone said on a forum, after resetting the ECU drive your Sti hard and let it learn?? Is this right?

[V8Huntr]

You can try the Vishnu reset. You can read about it here. I've never tried it myself tho.
Does the Vishnu trick really work?

But yea you can go ripping around after the reset and your ecu should advance but I'm not a tuner. Hopefully someone with more knowledge on this will chime in. I'm just an electronics and computer nerd so all I know is how the physical memory in the ECU works.