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Topic Review (Newest First)
06-07-2013 06:58 AM
DarthLEGO I have a Flashpaq for my LJ and have it reprogrammed right now. Will doing the rest above screw this up? Or should I just reset to "Factory" using the Flashpaq?
05-22-2013 03:52 PM
flflash So from reading this

[L]Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
Reconnect the Battery Cable
Turn Ignition Switch to the “On” position but DO NOT start the engine
Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Key “Off”[/

I am supposed to somehow believe that the headlight switch is magicly connected to the PCM.....wow I have a whole bunch of wiring schematics I need to throw away.
05-22-2013 02:27 PM
jeepndon
Quote:
Originally Posted by MrMopar View Post
ok i read a few threads on how to do this, it seemed no matter what i read there was always someone there to say thats not right

so here is what i would like to know. I want to reset the ecu, and here is how i did it, maybe its wrong. so please tell me what to do right

1 - disconnect positive battery cable
2 - disconnect negative batter cable
3 - hold both cables together for 30 seconds
4- connect positive back up
5 - connect negative

now thats exactly how i did it...is that right? did that reset my computer, i know on my last cherokee there was something like turning the lights on then off....i dont really remember

please let me know what i did wrong, and tell me if there is a way to do it for the transmission too.

my jeep is a 2000 wrangler with a 4.0 and a automatic trans!
YES this is correct when you touch the positive to the negitive it drains the residual power from the capacitors that keep the memory intact. besides that just leaving it disconnected for 3 min will do the same thing there are no capacitors that are that effecient to keep a charge for more than 5 min used in ANY car. After that just drive the car like normal and the computer will relearn the settings.
05-22-2013 10:52 AM
RevCo666
Quote:
Originally Posted by Neil F. View Post
Just do a google search on Chrysler PCM reset and this is discussed on MANY forums with basically the exact same discussions

I have not done it on the Jeep but have done it many times working on My 99 Durango. After disconnecting and reconnecting the battery (even after long peroids of time) the vehicle starts and runs just the same. After disconnecting the battery and turing the ignition to run for 30-45 seconds, then reconnecting the battery, it is slow to fire and idles very poorly for a brief while. Something is different.
Thanks for the info...
05-22-2013 10:49 AM
Neil F.
Quote:
Originally Posted by RevCo666 View Post
Correct me if I'm wrong but would just disconnecting the battery for an extended period of time clear out the CPU on the TJ model?
Just do a google search on Chrysler PCM reset and this is discussed on MANY forums with basically the exact same discussions

I have not done it on the Jeep but have done it many times working on My 99 Durango. After disconnecting and reconnecting the battery (even after long peroids of time) the vehicle starts and runs just the same. After disconnecting the battery and turing the ignition to run for 30-45 seconds, then reconnecting the battery, it is slow to fire and idles very poorly for a brief while. Something is different.

Resetting the '97-'01 PCM - NAXJA Forums -::- North American XJ Association



This is from a post on jeep forum:

Resetting the PCM Adaptive Memory

--------------------------------------------------------------------------------

Does this really work? From another Jeep forum:
vvvvvvvvvvvvvvvvvv

PCM Fast Learn Mode

I think most people know that the PCM performs several functions controlling Air Fuel ratios via Injector Pulse Width and Ignition Timing.

These “outputs” are controlled using the “inputs” received from all the sensors and then comparing these reading against a set of data tables burned into the PCM.

These “memory tables” are the brains that keep the engine running at low emissions and peak economy across the RPM band

What most people don’t know is that these memory tables change. They are “adaptive”, based on sensor readings, driving habits, engine performance and sensor tolerances.

Over time, the PCM Memory Tables become tuned to your engine.

Most folks know that disconnecting the battery for 15 to 20 minutes will reset the PCM to get rid of a Check Engine Light or Error Codes stored in the PCM.

However this DOES NOT reset the Adaptive Memory Tables in the PCM. Until recently I did not know how to do this.


This procedure first came to me from the folks at Avenger. I then verified it with a phone call to a Chrysler Engineer who had called me a year or so ago to ask about my experiences with a certain part on my TJ. I figured he owned me a favor. He had to check up on this for me. He called me back a week later and did indeed verify this procedure and what it does.

To the best of my knowledge it isn’t documented in any of the FSM.



Forced Flash

This very simple procedure will Erase the “Adaptive Memory” stored inside the TJ PCM and allow a new “Adaptive Memory” to be developed.

After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.

[L]Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
Reconnect the Battery Cable
Turn Ignition Switch to the “On” position but DO NOT start the engine
Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Key “Off”[/L]

Adaptive memory has nor been flashed, or erased from the PCM.

When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory.

When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”.

The PCM will collect data for Adaptive Memory for the first 50 Warm-up Cycles.


Warm-up Cycle

A warm-up cycle happens when all of the following conditions exist.

Engine is running
A raise of 40F in engine temperature must occur ABOVE the engine temperature at start-up
Engine Coolant Temp must reach at least 160 F.


Once your engine has gone through 50 warm-up cycles in at least a 500-mile distance the PCM adaptive memory is set. It WILL NOT Change unless you flash it out and start all over again.

This procedure is vitally important for this installation as the install includes much larger fuel injectors and a lot more air being forced into the engine.

However I believe a lot of folks may find it useful on their won Jeeps.

Does it work?

Yes!

You best performance will happen when the Adaptive memory is set to the current conditions of your engine. I tested this on the Dyno.

My test was to dyno run my Jeep after flashing the PCM and resetting the adaptive memory as I described above, with 50 warm-up cycles over a 525-mile distance.

You see the results in the charts posted above.

The last dyno run I did was performing after I flashed the PCM Adaptive Memory while on the dynamometer. We then ran the test again, using in essence the Base Setting that come in the PCM from the factory. This resulted in a loss of 9 HP and 17 ft/lbs of torque.

While this was only one test it certainly is an indicator to me of the importance of having the “Adaptive Memory” inside the PCM controlling the engine outputs based on the most current engine condition and not those set by the factory or those set in Adaptive Memory 83K miles ago.

I hope some folks will find this useful. I do believe it is a worthwhile task to do from time to time.

Frank

PS: We do not check for emissions here where I live, I would imagine if we did and if My Jeep failed I would be flashing the PCM Adaptive Memory and running the 50 warm-up cycles over 500 miles to reset things to optimum performan
05-22-2013 10:43 AM
RevCo666
Quote:
Originally Posted by Neil F. View Post
Not right away. If you read what rrich wrote and he is correct, there are capacitors in the PCM which store power for a long peroid (can't say how long)
Gotcha but when I ment a long period of time, I'm talking over 24hours ballpark I guess. I was just curious, not inciting an argument.
05-22-2013 10:32 AM
Neil F.
Quote:
Originally Posted by RevCo666 View Post
Correct me if I'm wrong but would just disconnecting the battery for an extended period of time clear out the CPU on the TJ model?
Not right away. If you read what rrich wrote and he is correct, there are capacitors in the PCM which store power for a long peroid (can't say how long)
05-22-2013 10:27 AM
RevCo666 Correct me if I'm wrong but would just disconnecting the battery for an extended period of time clear out the CPU on the TJ model?
05-22-2013 10:09 AM
Neil F.
Quote:
Originally Posted by Jeeper32 View Post
I know this is an old thread but I have a related question. Why would one want to do a reset like this? Would the reset help for a tire size change on an 06 rubicon? Is there any benefit to that or does the computer actually need to be set for the new tires?
The Adaptive Memory are areas of the PCM that adjusts parameters to compensate for the way the vehicle is driven. Under most circumstances, there is not a reason to do so.

The only way to adjust a Rubicon for a tire size change is through an electronc add on device you have to buy (there are several available).
05-22-2013 09:49 AM
UFOtestpilot
Quote:
Originally Posted by motopsycho67 View Post
Thank God we have rrich! What would we do without you! To call someone stupid for not yet learning something shows true ignorance. And to top it off you will reply to my statement with something other than a simple "sorry you're right" further showing you're ignorance. But hey, thanks for teaching me the proper way to reset my PCM. Hopefully that helps with the low idle and dying that just started after running my battery low from prolonged stereo usage. When I attempted to start my TJ she hesitated, sounded like it "jumped time" then wouldn't start till I gave her gas. Now she won't idle. I assume that this could be the quick easy (cheap) fix I'm looking for.
Thanks,
"Party Marty"
Necro-thread time warp. Anyhow, I hesitate to offer assistance lest I be accosted for trying.

Your issue can be fixed by first getting a good charge at the battery and immediately afterward setting your electrics up to adequately handle your stereo or not running your stereo for prolonged periods with the engine off. The injectors, fuel pump, and ECU/ECM require adequate power to operate properly.
05-22-2013 09:41 AM
VTBalla34
Quote:
Originally Posted by motopsycho67 View Post
Thank God we have rrich! What would we do without you! To call someone stupid for not yet learning something shows true ignorance. And to top it off you will reply to my statement with something other than a simple "sorry you're right" further showing you're ignorance. But hey, thanks for teaching me the proper way to reset my PCM. Hopefully that helps with the low idle and dying that just started after running my battery low from prolonged stereo usage. When I attempted to start my TJ she hesitated, sounded like it "jumped time" then wouldn't start till I gave her gas. Now she won't idle. I assume that this could be the quick easy (cheap) fix I'm looking for.
Thanks,
"Party Marty"
LOL bad morning at the office?
05-22-2013 09:04 AM
Jeeper32 I know this is an old thread but I have a related question. Why would one want to do a reset like this? Would the reset help for a tire size change on an 06 rubicon? Is there any benefit to that or does the computer actually need to be set for the new tires?
05-22-2013 04:58 AM
Neil F.
Quote:
Originally Posted by motopsycho67 View Post
Thank God we have rrich! What would we do without you! To call someone stupid for not yet learning something shows true ignorance. And to top it off you will reply to my statement with something other than a simple "sorry you're right" further showing you're ignorance. But hey, thanks for teaching me the proper way to reset my PCM. Hopefully that helps with the low idle and dying that just started after running my battery low from prolonged stereo usage. When I attempted to start my TJ she hesitated, sounded like it "jumped time" then wouldn't start till I gave her gas. Now she won't idle. I assume that this could be the quick easy (cheap) fix I'm looking for.
Thanks,
"Party Marty"

Good start for a first post.
05-22-2013 04:41 AM
kjeeper10
Quote:
Originally Posted by motopsycho67 View Post
Thank God we have rrich! What would we do without you! To call someone stupid for not yet learning something shows true ignorance. And to top it off you will reply to my statement with something other than a simple "sorry you're right" further showing you're ignorance. But hey, thanks for teaching me the proper way to reset my PCM. Hopefully that helps with the low idle and dying that just started after running my battery low from prolonged stereo usage. When I attempted to start my TJ she hesitated, sounded like it "jumped time" then wouldn't start till I gave her gas. Now she won't idle. I assume that this could be the quick easy (cheap) fix I'm looking for.
Thanks,
"Party Marty"
#1 the thread is 2 years old
#2 who called someone stupid ?
#3 welcome to the WF
05-22-2013 03:26 AM
motopsycho67
No one should ever be called stupid...

Thank God we have rrich! What would we do without you! To call someone stupid for not yet learning something shows true ignorance. And to top it off you will reply to my statement with something other than a simple "sorry you're right" further showing you're ignorance. But hey, thanks for teaching me the proper way to reset my PCM. Hopefully that helps with the low idle and dying that just started after running my battery low from prolonged stereo usage. When I attempted to start my TJ she hesitated, sounded like it "jumped time" then wouldn't start till I gave her gas. Now she won't idle. I assume that this could be the quick easy (cheap) fix I'm looking for.
Thanks,
"Party Marty"
07-09-2011 11:12 AM
rrich He He - lots of "armchair" theories and procedures. But very few are actually based on fact. Some are factual for other vehicles, but not Jeeps. That leads to the wrong conclusions about the procedures and effects. Fords, Chevys, Toyotas, Mercedes, etc., all have similar but different procedures. There is not one universal way. Some even will not clear the long term memory with a long term battery disconnect. Some can retain that memory for years just sitting on the shelf. Some erase everything in a momentary disconnect. On some you have the use the headlights or use the correct scanner to do it.

Jeeps are relatively easy and straight forward.

There are TWO levels of memory (Jeep):
1. A temporary volatile memory that stores codes.
2. The other is deeper that stores the long term adaptive memory. It adjusts to the small differences in sensors, and even to your driving style. If the sensor is detecting something too far from specs - out of range, it sets the short term codes. That may be the sensor's fault or something else causing it.

A quick disconnect clears the codes, but does not clear the adaptive memory.
Disconnecting the battery for 8 hours or more clears out EVERYTHING - resetting it back to default - just like it was a totally new computer.

FACT - TRY IT! -
If flashing headlights, touching cables together, blowing the horn, discharged capacitors in the PCM - then it would be very easy to put a voltmeter on those disconnected cables before shorting them or playing with the headlights and actually see the voltage it's going to short out!
Seems like nobody is smart enough to try that, but they believe all the rumors and wishful thinking.
How can you short out a voltage that does not exist?

If you use a good scanner that can get deep into the memory and actually see the curves, charts, and mapping you could try all the phony methods - before and after and actually see it does nothing.
But a deep cleaning - 8 hours - you'll see it resets everything.

When a programmer "flashes" the PCM to modify it slightly, all he's really doing is putting new curves into the long term memory - establishing new "desirable'' points to cause it to try to maintain those points.
For the most part, the stock points and curves are the best overall programs. The 8 hour disconnect re-establishes those "desired" points (default.)
07-09-2011 04:51 AM
kjeeper10
Quote:
Originally Posted by Wheel2Work
Here's the procedure from another thread on this site

1. Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
2. Reconnect the Battery Cable
3. Turn Ignition Switch to the "ON" position but DO NOT start the engine
4. Turn Headlight "ON"
5. Turn Headlights "OFF"
6. Turn Ignition Key "OFF"

The PCM Adaptive memory has now been flashed, or erased from the PCM.

For the full thread: http://www.wranglerforum.com/f5/ecu-reset-360.html
From what I gather on here, that procedure is bogus. A disco of a couple
Minutes is good to clear any codes. A full 8 hours plus or a dealers scanner can actually reset the ECU and begin it's relearning process

I replaced my 02's at 160,000 and my jeep ran rough. I disco'd overnight and all was good.
07-09-2011 12:02 AM
Wheel2Work Here's the procedure from another thread on this site

1. Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
2. Reconnect the Battery Cable
3. Turn Ignition Switch to the "ON" position but DO NOT start the engine
4. Turn Headlight "ON"
5. Turn Headlights "OFF"
6. Turn Ignition Key "OFF"

The PCM Adaptive memory has now been flashed, or erased from the PCM.

For the full thread: http://www.wranglerforum.com/f5/ecu-reset-360.html
07-08-2011 10:53 PM
MrMopar
jeep computer and doing a reset

ok i read a few threads on how to do this, it seemed no matter what i read there was always someone there to say thats not right

so here is what i would like to know. I want to reset the ecu, and here is how i did it, maybe its wrong. so please tell me what to do right

1 - disconnect positive battery cable
2 - disconnect negative batter cable
3 - hold both cables together for 30 seconds
4- connect positive back up
5 - connect negative

now thats exactly how i did it...is that right? did that reset my computer, i know on my last cherokee there was something like turning the lights on then off....i dont really remember

please let me know what i did wrong, and tell me if there is a way to do it for the transmission too.

my jeep is a 2000 wrangler with a 4.0 and a automatic trans!

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