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Unread 06-04-2008, 03:15 PM   #1
n19948
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How to reset the PCM

Does anyone know if this procedure works on the JK?

This very simple procedure will Erase the “Adaptive Memory” stored inside the 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.

Please perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.

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”


The PCM Adaptive memory has now 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.

I found this in the Cherokee form.

Thanks for any help.

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Unread 06-04-2008, 03:51 PM   #2
MacK
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Hmm.. I wonder if this really improves anything. I mean I get 21MPG in my Jeep. When I first got it, the engine used to rev up but it stopped. Not sure if it was because when I got it was cold out and it was just warming itself, or what. Oh well Let me know if you try this out!
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Unread 06-04-2008, 04:08 PM   #3
BiGEN
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my revs high when my jeep sit for a long while.. and its still 80 degrees out
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Unread 06-04-2008, 05:18 PM   #4
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Sure it does, but it doesn't accomplish anything. Your Jeep will not misteriously run better or have more power. This is usually done to erase codes.
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Unread 06-04-2008, 08:59 PM   #5
n19948
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I'm having trouble with the torque converter lock up on the 2 to 3 shift - it shutters. The dealer replaced the TC at 800 miles and cleared the pcm and it worked great for 300 miles and it started again. They cleared the pcm 2 days ago and it was great for until today. The mechanic said it looks like the memory is learning wrong so I was just thinking about clearing it again myself and seeing what happens.

Everything else is great. I get 22 mpg and all the shift points are good - just a little shutter on the 2 to 3 shift. Just trying to make it perfect.
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Unread 01-10-2009, 11:42 AM   #6
malton
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Quote:
Originally Posted by n19948 View Post
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.
"to ground"...help an idiot out here...to the negative cable/terminal, or...?
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Unread 01-10-2009, 12:09 PM   #7
Evil_Trolloc
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Yes, the ground would be the negative cable, post, all the chassis (just don't hold it to a painted part or a piece of metal fastened to plastic. Best to go right to the negative terminal at the battery
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Unread 01-10-2009, 03:32 PM   #8
thundercat900
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Very wrong and could be very bad for any computer controled vehicle. NEVER remove the positive terminal first and NEVER NEVER install the positive terminal LAST.

You should always remove the negative terminal first and install the negative terminal last to help prevent voltage spikes into the vehicles modules.

I'm not saying that every time you spark the positive terminal back on it will wipe out a ecu....but why take a chance.

But I have used many times resetting the pcm by unhooking the netative terminal and touching it to the positive terminal for at least 10 seconds. This will not short anything out because the battery is open and there will be no current flow thru it.
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Unread 01-11-2009, 02:38 PM   #9
cerbomark
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On Chevy it was just dis connect battery overnight. I would not try what was suggested with the battery terminals unless you are 100% sure of that.
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