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Discussion Starter · #1 ·
Last week I resetted the ECU to see if it will give me better gas milage. Well sad to say on a full tank a gas I only got 150. No one I know with a 2.0T has ever seen it that low before, so i'm a little confused. 1 dealership said thats normal the other dealership I called said there's something wrong. Maybe I did it wrong? Can someone gives me steps to resetting the ECU and also the battery I want to try the battery, but I can't find a thread that explains it well enough.
 

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War Eagle!
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I just unplug the negative terminal on the battery for about ten minutes. This resets the ECU
 

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War Eagle!
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you have to loosen the clamp that is holding the wire to the terminal (the terminal is on the left side of the battery, the screw you want to loosen is on the right side of the terminal). Then you lift the clamp off the terminal

Here's a pic of the battery. the part you want to take off is the metal piece on the left terminal
 

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What exactly did you do to reset the ECU because it seems you performed this task without even knowing how to do it correctly?

...Either way, the dealership that told you 150 miles on a full 16 gallon tank is NORMAL needs to go shoot themselves, should be AT LEAST double that.
 

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Also wheb u unplug the neg and leave it hanging make sure it doesnt touch any other metals because it will still ground
 

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Also wheb u unplug the neg and leave it hanging make sure it doesnt touch any other metals because it will still ground
Um it's already ground, i think you mean positive cable not to touch, which you shouldn't be taking off...
 

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Discussion Starter · #8 · (Edited)
you have to loosen the clamp that is holding the wire to the terminal (the terminal is on the left side of the battery, the screw you want to loosen is on the right side of the terminal). Then you lift the clamp off the terminal

Here's a pic of the battery. the part you want to take off is the metal piece on the left terminal
http://img440.imageshack.us/i/72527338.jpgSo all I do is unscrew that bolt that I have circled or the one next to it and then lift up the clamp off and leave it there for about 10 mins and that should reset the ECU? Sorry I'm making sure I'm doing this right because I heard this can **** up your car royaly if you do it wrong.
 

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Um it's already ground, i think you mean positive cable not to touch, which you shouldn't be taking off...
this^^. The ground that you are pulling of the neg terminal is attached to the metal body, so touching it to metal touches metal to metal doing.... nothing.

here is nother pic if that helps. You might be able to do the other bolt like you showed... but the bolt my socket wrench is on is much eaiser, it just tightens/losens the clamp around the metal ring around the terminal. then just pull the ring off the terminal.



You can't really mess up your car with the neg, that is the positive you have to worry about which you have no need to touch as said, and it has like 3-4 bolts you mess with). Really the only way to mess it up with the neg is if you play around with the neg/ground cable and slap it repeatily against the neg bat terminal trying to get an arc, and it still probably won't do much.

I I think the danger has more to do with jumping a car the wrong way and sparks mixed with the gases can cause explosions.

FYI you might get a spark when reconnecting, it isn't that big of a deal, just keep putting it on. Also make sure your alarms is off prior to doing this as if you reconnect it will spark and blow a LOUD horn in your ear! lol
 

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I thought low mpg was normal after resetting the ECU? 150 is far from normal but i thought it was expected. I reset mine last week and was getting like 21mpg until the car 'learned' my driving habits again.

And cant you just pull the fuse for the ecu?
 

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The whistles go WOO! WOO!
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Also wheb u unplug the neg and leave it hanging make sure it doesnt touch any other metals because it will still ground
Um it's already ground, i think you mean positive cable not to touch, which you shouldn't be taking off...
:squint:

With at least one terminal of the battery unhooked you can touch whatever to whatever. (edit: unless there's a big capacitor in the system somewhere that i don't know about, then don't short the leads. Pretty unlikely though)

But yes, a few mins of disconnect will reset it, and your mileage is way out of line. ECU reset will likely not help. Go back to dealer, or to another dealer.

When you hook the battery back up, make sure all your doors are closed, or the alarm will go off. Scared the **** out of myself this past weekend doing just that.
 

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My way.

1. Open door
2. unplug negative terminal
3. go to door
4. press the door swith button on the back of the door frame, that is on the car (not on the door) a couple times
5. connect negative terminal.

What this does, is drain the residual charge thats left in the system, but not enough to reset the stereo pre-sets. It drains it, because the door windows will want to go up and down, when pressing the button.

Your gauge readings should be now reset, along with the ECU.
 

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You don't have to pull the negative terminal off unless you want to reset all radio stations and navigation places (if you have nav)

Small fuse box close to Battery... open up and look for 10amp marked ECU1
Pull it out for a minute and let it back in.. it will reset it.
 

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The whistles go WOO! WOO!
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You don't have to pull the negative terminal off unless you want to reset all radio stations and navigation places (if you have nav)
Your way is better, but for what its worth: If you pull the negative cable, the address book stays, haven't checked my radio stations yet (I don't listen to the radio). I think the XM presets stayed.
 

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Your way is better, but for what its worth: If you pull the negative cable, the address book stays, haven't checked my radio stations yet (I don't listen to the radio). I think the XM presets stayed.
I'm pretty sure I lost everything when I pulled the battery cable on mine including XM presets. Jay's way ftw...
 
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