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how do feset my ecu? i have heard of a few ways from friends just wondering which way i should do it. thanks guys
 

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I BELIEVE that you disconnect the battery for about 5 minutes, hook it back up, than let the start the car and let it idle for about 5 minutes. Pretty sure this is it, but someone will correct me if I'm wrong[8]
 

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I did this when I first heard about it, it seemed to very slightly clean up my idle. I may have just imagined it though.
I did it again after I had installed my short ram intake, just to make sure that it woudl recognize the difference.
 

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Discussion Starter #5
yeah i did it last night when i installed my headers and it seems to idle alot better still rough at times but alot better
 

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It is always recommended that you reset you ECM after adding a mod do that ECM can imediately take advantage of the modification.

The ECM has a learn procedure which basiclly takes notes of your specific driving style, environment, among may other things.

One thing to note is that after reseting the ECM the ECM will be in relearn mode and may run better or worse for a few days. don't mistake this with a problem with your mod's.
 

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What the hell is an ECM and ECU? Please excuse my ignorance, I am here to learn from all the educated ones.
 

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its just like "you say tomato, I say tomato"

ECM= Engine Control Module
ECU= Engine Control Unit
PCM= Powertrain Control Module

Are almost always used interchangeably.
 

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Yeah it is basically the computer that manages the engine.
 

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i've heard that you should wait closer to 20-30 minutes. i always disconnect it and hit the brake pedal a couple of times to speed things up. you're basically just waiting for whatever reserve capacity is in the system to die out so that the ECU will completely reset itself.

Mike

PS- watch out for that damn alarm! sometimes it likes to go off when you hook it back up. i've found leaving the alarm in valet mode eliminates that, though.
 

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Who here on this forum knows the ECU/PCM/ECM component intimately ?
I would like to know why you need to disconnect the power from the ECU/PCM/ECM for 15 to 20 minutes for it to lose it's memory/settings.
Does it have a temporary backup battery(capacitor) that keeps it's charge for 15-20 minutes to perserve the ECU/PCM/ECM settings during a normal battery change ?
 

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i have a 2000 ford focus not getting an o2 sensor, catalytic converter and other readings from the ecm. i had ity replaced with a used one at the ford dealer have the same problem was wondering if there is a fuse or relay and could that might be the problem
 

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papi..idk what your problem is..take it back have them look at it. should have some sort of warranty

you need to wait 30minues at the least. the gauges will make a sweep. then you need to drive your car so the ECu can relearn your driving habits.

after typing i just realized how old this thread was
 

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Take the Neg or Pos cable loose for 3-4 Min and replace it thats all that needs to be done

If you want to do a quick reset then I take the neg cable loose and touch it to the pos side , No it wont arch then put the neg cable right back on and that clears everything quick

Tom
 

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If you plug in any generic code reader or scan tool and "Clear all emissions related data" or just "Erase" the codes it will automaticly reset the ECU (PCM)
 

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sorry i know this is a old tread but yeahhh...

So long story short i got a fc 65tb, slapped it on and the car didnt run right, ran out off time before work started and slapped the OEM stuff back on.

So i had my battery unplugged the whole time and with the oem tb back on the car couldnt idle long then 30sec. It took my car a good 30min car ride (half city/freeway) to learn how to idle again.

So is there any proper way to re train your ecu just to idle? i cant imagine just sitting in your garage starting the car a million times to be ideal.
 
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