To erase a code, use a scanner tool to remove that specific code. To dump all codes, remove the battery cable for 10 minutes, then reconnect. If you want to erase the adaptive memory completely and set the ECU to a new start up, remove the cable 10 minutes, reattach the cable and turn the key to the run position. While the key is in the run position, turn the headlights on, then off. Turn the key to the off position. The ECU will then be completely reset for a first start up.

 

Not to hi-jack, but what are the benefits of doing that? The whole ECU-restart. I've never done so and if there's some sort of benefit I'll probably do that. :angel:

 

Erasing the adaptive memory is helpful when the conditions of the vehicle have been changed, like a bigger throttle body, cold intake system, different cam, head, exhaust or forced induction system for example. The way the engine adapts to these will be different than a stock engine and it will help it adjust faster and better.

 

I under stand that, just never heard of using the head lights on and off to clear the adaptive memory. My 95 Neon will loose all adaptive memory when disconnected for some time. But my 98 Z71 never does. For that I use a Snap-on scanner to clear everything.

Will

 

After the reset, When you start the engine it will be running off the preset numbers from the factory

So many warm up cycles the PCM will collect data for adaptive memory.

I always do it after any performance mod. My jeep ran a little ruff after I replaced my 02 sensors. After the reset the jeep runs great

 

I under stand that, just never heard of using the head lights on and off to clear the adaptive memory. My 95 Neon will loose all adaptive memory when disconnected for some time. But my 98 Z71 never does. For that I use a Snap-on scanner to clear everything.

Will

I think turning the lights on drains the stored electricity in the capacitors.

 

Information comes straight from a Chrysler engineer. I'm not certain how it clears the memory, but I can assure you that it does!

 

It did not work on my 99 Sahara.

 

When you get those codes - simply write them down on the sidewalk with chalk, then wash off the chalk. It will do as much as what he said.

There's two ways on a Jeep - one is use the DRB scanner that the dealer uses (the new Snap-On might,) the other is disconnect the battery for at least 8 hours.

If you use a decent link to your laptop and have the software you can see what's in the adaptive memory. You can see the chalk/sidewalk method is as effective as turning on headlights, touching cables together, killing a sheep at midnight or visiting the Wailing Wall.

Where do all these rumors come from? Certainly not Chrysler. Or -- I wonder if they promote them to stop the DIY?

A short disconnect erases codes and the temporary volatile memory, but it has no effect on the deep adaptive memory.

 

The sticky

http://www.wranglerforum.com/f5/ecu-reset-360.html

 

Believe what you want to believe. Just because someone put it as a sticky makes it true?

Use a scanner that can "see" the deep adaptive memory - you'll see for yourself there is no Easter Bunny.

That's exactly why this country is failing - people believe it's true because something is in print somewhere.

 

Believe what you want to believe. Just because someone put it as a sticky makes it true?

Use a scanner that can "see" the deep adaptive memory - you'll see for yourself there is no Easter Bunny.

That's exactly why this country is failing - people believe it's true because something is in print somewhere.

Aren't your supposed rebuttal and subsequent claims also in print? :facepalm:

 

Just disconnect the battery's negative lead or ECM for 2 minutes, that is more than enough to clear the Check Engine light and that type of code. To prevent your radio station presets and clock from being reset, you can disconnect the ECM (three plugs) for 2 minutes instead of the battery, it has three quick connectors.

There's no need for anything else beyond this, no fancy procedure like the above is needed at all.

Or do nothing, the code and the check engine light will clear themselves within a short while after you start driving it after you replace the TPS.

 

Jerry's correct - some of the time you don't need to clear the deep memory. Erasing a code will also clear the temporary memory.

But often you see thing's like a TPS, temp sensor, etc. was replaced, and it had no effect or even got worse.

The PCM still remembers how it got the defective part to work as best it could, it doesn't know it's now a new part, so it tries to use it the same way. If you drive it long enough, the computer will relearn, but it can take many many miles to learn - depending on what it is, it may be 100-500 miles! That's why so often you see complaints that "I replaced it 4 times before I got a good one." They were all good, it just took a long time for the computer to remember how a good one was supposed to work.

Deep cleaning - 8 hours - resets the computer back to default - the original knowledge the factory put in.

The 2 minute, 10 minute etc method is like removing the cover off a book - no longer identifiable, but the knowledge inside is still there.
Deep cleaning destroys the entire book.

Spend $30 or so and get a data link from the computer to your PC or laptop - they come with free software. You can see for yourself!

Your other option is to continue to live in fantasy land.

 

I've disco'd the battery overnight. Seems to always work

Shouldn't the sticky "be removed" I mean, if the information is not the correct method, let's remove it. I see that method mentioned all the time on here.

 

Another source for information on the topic:
Learning mode???? - JeepForum.com

 

opcorn:

 

Think about it!

If touching the cables together or to ground actually did something, then there would be a voltage on the positive lead right after you disconnected it.

TRY IT - MEASURE IT - use a high impedance voltmeter like a digital so the meter itself doesn't discharge the "capacitors."

There is no voltage to discharge!

How can you discharge something that doesn't exist?

Someone made up that story and it's been repeated many many times as Gospel - it continues to grow, and expand.

There are so many ways to check the validity of it - but it seems nobody has enough intelligence to even try the simple things.

Question - What happened to the people that used to off-road when we had to make things for ourselves, even wide rims, no store-bought sub quality stuff was available then? They had to be able to think!

Have they all been replaced by scizzorbills?

But - ask me if I care?

 

I assumed it was like using the "control-alt-delete" function on any home computer, a set program that does what it does (reboot the system) Not so much the electrical theory behind it but a process of steps when followed would clear the ECU or whatever the steps were designed to do ??

 

If you can find the "control" and "Alt" and "delete" on the Jeeps PCM let us know where they are - it would probably work. If your PC's buttons didn't evoke that re-boot program, what do you do? Remove all power!
But like your computer - turning the power off re-boots it, but the PCM is designed not to lose the deep memory when you change batteries, or even when the voltage drops a little every time you start it. (Your PC will drop out with a voltage brown-out.) The PCM "holds" the memory longer than a few minutes - several hours.
Yes, it has capacitors that hold it - but they are deep behind diodes, preventing you from discharging or even detecting them.

GM used to have 2 memories - the Intergrator and the Block Learn. The Intergrator cleared with a batt disconnect, the Block learn had to be "force cleared" or given many miles to relearn. That's why when you drove grandma's car it seemed sluggish for a long time, but after while it learned to come alive after you drove it awhile. Disconnecting the battery did not reset it to default. GM eventually recognized that as a problem.

Ford's EEC and Chrysler's adaptive memory was more permanent - it held even without power for years - even on the shelf. It had to be "force cleared" with a special signal to clear it.
Ford's MCU instantly lost it's memory and codes even with the ignition being turned off - too fast - it too caused problems.

Jeep learned from experience - took the middle road. They designed theirs with 2 memories too, one volatile, the other semi-volatile. Short term a 2 minute disconnect clears it. Long term it could be "force cleared" with a DRB, otherwise a longer term power disconnect would accomplish the same thing.

Easy to see, easy to check.

But the rumor will continue.

 

If you can find the "control" and "Alt" and "delete" on the Jeeps PCM let us know where they are...

That's like when the tech guy tells you to hit any key, and you respond with, I can't find the ANY key.

 

Well there ya have it :thumb:

But you mean to tell me my jeep doesn't have control-alt-delete buttons? Thought it did :hide:

 

Unhooking the battery cables and touching them together is how I've always done mine, and while cables are off, turn key on and off, a 1 minute procedure, works on my tj and my xk

 

Unhooking the battery cables and touching them together is how I've always done mine, and while cables are off, turn key on and off, a 1 minute procedure, works on my tj and my xk

You read through the thread?

 

I play my Jeep a lullaby and it goes to sleep and clears it's memory. In all seriousness no more than a few minutes like Jerry said. In tech school we were taught that 15 minutes was way more than enough. So anything in-between 2-15 minutes is plenty.

 

See? It still persists even though it's so simple to actually prove or disprove it!!!!

Obama wants to lower taxes!

If you turn in your guns crime will automatically stop!

The world is flat!

I don't care anymore.

 

See? It still persists even though it's so simple to actually prove or disprove it!!!!

Obama wants to lower taxes!

If you turn in your guns crime will automatically stop!

The world is flat!

I don't care anymore.

Agree. Ur a funny man :rofl:

 

No no, you're all wrong. To clear the memory you have to remove the battery, turn it three rotations counterclockwise, reinstall the battery, unhook the left headlight, turn on your windshield wipers and your hazard lights for 13 seconds while hopping on one foot, rotate your tires, discharge the flux capacitor by removing the muffler bearings and grounding them to the engine block, turn on your right turn signal while reconnecting the left headlight, disconnect your battery, drink til you pass out, wake up, and reconnect your battery. It's that easy. Though if you are in the southern hemisphere you have to go clockwise. This procedure only works if you record a video and post it to youtube though.

 

No no, you're all wrong. To clear the memory you have to remove the battery, turn it three rotations counterclockwise, reinstall the battery, unhook the left headlight, turn on your windshield wipers and your hazard lights for 13 seconds while hopping on one foot, rotate your tires, discharge the flux capacitor by removing the muffler bearings and grounding them to the engine block, turn on your right turn signal while reconnecting the left headlight, disconnect your battery, drink til you pass out, wake up, and reconnect your battery. It's that easy. Though if you are in the southern hemisphere you have to go clockwise. This procedure only works if you record a video and post it to youtube though.

Done