ECU Re-learn Procedure (without disconnecting battery!) - Jeep Patriot Forums
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post #1 of 41 (permalink) Old 05-04-2010, 05:11 PM Thread Starter
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Lightbulb ECU Re-learn Procedure (without disconnecting battery!)

As noted in a previous discussion (Spark Plugs), there are certain benefits to resetting your ECU. Apparently, the guys over at CaliberForumz have stumbled on a way to do this procedure without leaving your battery disconnected for an hour (http://www.caliberforumz.com/showthread.php?t=14197)

1). Turn ignition to Run, but do not start engine.

2). Wait for all idiot lights to turn off (last one will be the the throttle indicator - the two half-moons w/ a lightning bolt between them).

3). Over the course of 15 seconds, slowly depress the throttle all the way to the floor. Try not to waver or be too jerky, just a nice slow, smooth push.

4). Over the next 15 seconds, slowly let the throttle out in the same manner.

5). Allow car to sit for about an hour. (This is in the original procedure list, but i tried waiting just a minute and it worked anyway.)

6.) Start car and drive as you normally would.


Your car should respond differently, almost instantly. The ECU fuel maps are reset to factory original specs, and the computer "forgets" all the previous info it has learned about your driving style. This gives the computer a fresh start to accomodate for a new driver (if you bought your Pat used, like i did), replaced/upgrades parts, change in altitude, etc.

I tried it last night, and it definitely makes a difference. I noticed right away that the throttle response was more immediate. I reset the ECU and drove home, but seeing as how i was in choppy traffic (lots of idling, broken up by low-medium acceleration), this is what the ECU began to learn.

When i drove it again that evening, the tranny gears seemed to sync up smooth as silk at 2500rpm, which it didn't before. But when pushed harder (over 3000rpm), the tranny had a harder time matching gears. So i did the relearn procedure again, this time accelerating out to about 4000rpm before shifting, accelerating hard, lots of throttle off the line. Sure enough, it wanted to run out to 4k or so before syncing up for gear changes. Shifting at about 2500rpm was slow and painful. But torque steer, which used to be bad, has been all but eliminated to my amazement! The difference is quite noticible.

So, that said, it is important that if you do this, you drive your normal style for the first couple miles. This will give the computer the best opportunity to accomodate your driving style, thus giving the best results.

Over the course of time, the computer will create a very specific fuel map in it's best effort to give you the power you want while protecting the engine and offering the best fuel mileage. The "brand new" feel from a fresh reset will fade away, and you'll be left with something probably very near what you had before, but please keep in mind that this is just how the computer is made to work.

I plan to perform another reset tonight, and hopefully give my ECU a chance to get a more accurate picture of my driving profile, rather than the ultra-conservative one and the high-spirited one I subjected it to last night.

Hope someone else finds this useful!
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post #2 of 41 (permalink) Old 05-04-2010, 05:57 PM
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nth256... thank you! This is an exciting thing to try. I will have to remember ECU when I want to find this tread again sometime this Summer when I am willing/able to start fresh.

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post #3 of 41 (permalink) Old 05-04-2010, 06:46 PM
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thanks for the tip.
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post #4 of 41 (permalink) Old 05-04-2010, 06:47 PM Thread Starter
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My pleasure.

This may also be helpful for folks in places like California who get seasonal blends of gas. You're still going to suffer in the summer (upped ethanol content), but it may help out a little.
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post #5 of 41 (permalink) Old 05-05-2010, 09:30 PM
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This has actually been out for a while.They had a different name for it but the same procedure.It defenitely worked for me no more hesitating feel when first accelaritng

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post #6 of 41 (permalink) Old 05-06-2010, 05:05 AM
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is this just for petrol riots? or for diesel ones as well?
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post #7 of 41 (permalink) Old 05-06-2010, 09:18 AM
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Doesnt work with manual gearbox or Diesel engine !!---Also results seem for better for the 2litre Engine with CVT a la' Pat 4x2 & Caliber. Amazing results with my Caliber , no difference with my Diesel Pat or my 2.4 Avenger. .....Talking of the Avenger, I have now got up to 36.4 MPG ( Imp) on my EVIC.

Just swapped red Classic X , for, Green Auto SE " Spirit " 2.5 Petrol Limited edition X still 4x4,


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post #8 of 41 (permalink) Old 05-06-2010, 01:03 PM Thread Starter
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Negative, tiptronic - I have a 5-speed and it worked for me.
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post #9 of 41 (permalink) Old 05-06-2010, 01:12 PM
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Over a distance of 3000 or so (mainly highway) kilometers, my gas consumption increases slightly, and RPMs increase for a given speed. This procedure brings everything back to normal. The procedure given on this forum in the past has been 30 sec. down, 30 sec. up, ignition off for one minute.
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post #10 of 41 (permalink) Old 05-06-2010, 01:29 PM
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Dont forget the Placebo effect!

Just swapped red Classic X , for, Green Auto SE " Spirit " 2.5 Petrol Limited edition X still 4x4,


Ex 07 Patriot CRD Sport , UK ( with lots of chrome goodies )
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post #11 of 41 (permalink) Old 05-06-2010, 02:30 PM Thread Starter
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Quote:
Originally Posted by tiptronic View Post
Dont forget the Placebo effect!
I've got a fairly accurate butt-dyno, thanks. I've read about 5-speed Calibers not noticing a difference; I'm just saying that I HAVE a 5-speed Patriot (equivalent in most regards to a 5-speed Caliber R/T), and I HAVE noticed a difference. Guess you'll just have to trust me on that, though. But I've got nothing to gain by lying about this, so take it for what you will.

My assumption is (and my experience since the re-learn seems to support) that it mostly affects the elec. throttle control (rate of RPM falloff for up- or down-shift scenarios), since there isn't any computerized method to affect the manual transmission behavior (it wouldn't be a manual, were that the case).

If i didn't know what I was looking for, i might not notice what's happening; however, there IS an appreciable difference in the behavior of the car after I performed the re-learn procedure.

My hope is that it DOES work for other people (5-spd or not), so I'm not wasting my time defending myself from the placebo arguement.

To wit: 08 Jeep Patriot Sport, 4x2, 5-spd manual, 2.4L GEMA engine, aftermarket rims, Yoko GeoLanders (235/65/15), OEM or equivalent air/oil filters (haven't pulled them out to check yet), factory exhaust, no aftermarket engine, electronic, or transmission enhancements. BONE STOCK, save for the wheels. Which are kinda sissy-looking, but they came with the car. The curse of buying used, i guess.

Last edited by nth256; 05-06-2010 at 02:40 PM.
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post #12 of 41 (permalink) Old 05-06-2010, 02:35 PM Thread Starter
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Quote:
Originally Posted by neilcrichton View Post
Over a distance of 3000 or so (mainly highway) kilometers, my gas consumption increases slightly, and RPMs increase for a given speed. This procedure brings everything back to normal. The procedure given on this forum in the past has been 30 sec. down, 30 sec. up, ignition off for one minute.
"Back to normal" is kinda missing the point. It brings it back to generic factory settings. The way you drive affects what the learned "normal" is for your setup. Not critiquing your driving style; there are other factors such as altitude, terrain, how you use your vehicle, load, etc. that have just as much affect as your right foot habits.

But what i did NOT know is that this had been brought up here before. Bad on me for not doing a search first , my apologies. Thanks for mentioning that.
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post #13 of 41 (permalink) Old 05-07-2010, 12:16 AM
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Quote:
Originally Posted by nth256 View Post
"Back to normal" is kinda missing the point. It brings it back to generic factory settings. The way you drive affects what the learned "normal" is for your setup. Not critiquing your driving style; there are other factors such as altitude, terrain, how you use your vehicle, load, etc. that have just as much affect as your right foot habits.

But what i did NOT know is that this had been brought up here before. Bad on me for not doing a search first , my apologies. Thanks for mentioning that.
I do 90% of my driving at highway speeds, usually at about 110 kph (about 65 mph). At that speed, I usually get about 26 mpg (US), and the engine is running at about 2200 - 2300 rpm. If I have spent a lot of time only driving around town - low speed, lots of stop and go, the engine "learns" these conditions and adjusts accordingly. Then, when I get on the highway again, engine speed at 110kph is up around 2400 rpm, and fuel economy is down. Resetting the computer, as I stated before, drops the rpm, and improves mpg.
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post #14 of 41 (permalink) Old 05-07-2010, 11:55 AM Thread Starter
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Quote:
Originally Posted by neilcrichton View Post
I do 90% of my driving at highway speeds, usually at about 110 kph (about 65 mph). At that speed, I usually get about 26 mpg (US), and the engine is running at about 2200 - 2300 rpm. If I have spent a lot of time only driving around town - low speed, lots of stop and go, the engine "learns" these conditions and adjusts accordingly. Then, when I get on the highway again, engine speed at 110kph is up around 2400 rpm, and fuel economy is down. Resetting the computer, as I stated before, drops the rpm, and improves mpg.
Whatever works for you, man! Sounds like you know what you're doing; I just don't want some newb thinking this will automagically give them extra horsepower and 88 mpg.

I'm personally just hesitant about performing too many resets on the ECU, only because i'm not sure how many read-write procedures the chip will handle before it starts corrupting memory sectors. Not even sure IF that's an issue to be concerned about.

I read a Murikami novel about the dangers of re-shuffling too many times. Doesn't sound pleasant.

Last edited by nth256; 05-07-2010 at 12:00 PM.
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post #15 of 41 (permalink) Old 05-07-2010, 01:47 PM
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Quote:
Originally Posted by nth256 View Post
My assumption is (and my experience since the re-learn seems to support) that it mostly affects the elec. throttle control (rate of RPM falloff for up- or down-shift scenarios), since there isn't any computerized method to affect the manual transmission behavior (it wouldn't be a manual, were that the case).

If i didn't know what I was looking for, i might not notice what's happening; however, there IS an appreciable difference in the behavior of the car after I performed the re-learn procedure.
I'm not sure how to train the computer to get good gas mileage with the 5 speed. In the city, I'm not heavy footed on the gas pedal but prefer to let the engine rev up a bit say 3000 - 3500 rpm before shifting. On the highway, I drive around 60 - 65 mph. After a recent oil change at the dealer, I notice the RPM fall off especially before shifting into 2nd gear and the city gas mileage seems worse than before the oil change. Another unknown variable to this whole thing is the percentage of alcohol in the Regular gas that I buy around here.

Last edited by miketmx; 05-07-2010 at 07:19 PM. Reason: lowered RPM after checking the tach
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