Disconnected battery = reset ECU memory
06-25-2005, 09:46 AM
#1
Disconnected battery = reset ECU memory
I read somewhere that disconnecting the battery resets the ECU's memory of how you drive.
My question is, "Does that happen immediately, or only after a certain period of time?"
I'm installing a new battery and I would prefer NOT to give my ECU amnesia.
My question is, "Does that happen immediately, or only after a certain period of time?"
I'm installing a new battery and I would prefer NOT to give my ECU amnesia.
06-25-2005, 09:59 AM
#3
I don't know exactly how long you have, but I think its on the order of 30 mins. So you should have plenty of time to swap in your new battery. You will lose radio station presets, clock etc., those are independent of the ECU memory.
06-25-2005, 03:58 PM
#5
Originally Posted by InsneDrmr
how would the car know how you drive?...i mean ive heard of wear in certain spots on the clutch due to the driver, but never anything on the ecu.
Seriously, the ECU is a computer with a self-learning function that adapts various engine functions to how you drive.
Drive like a granny? The ECU will produce one set of variables to match. Drive like Mario Andretti? The ECU will produce a different set of variables to match.
Now, if we could only get the drivers to be so smart!
06-25-2005, 04:38 PM
#7
Disconnecting the battery long enough will clear all codes if stored in the memory of the ECU. But, this actually does nothing but make the car have to go thru several drive cycles to re-learn everything. If there were codes stored before the disconnection, you can guarantee that it will come back soon if the faulty sensor hasn't been changed. That is why if you change a faulty sensor, and have to disconnect the battery or not, just as long the battery isn't disconnected too long (several hours or so), you should use a scan tool or consult to clear the code so that the car can recognize the new sensor and adjust to it right away. The car will relearn much faster with the new sensor.
06-25-2005, 04:46 PM
#8
Member who somehow became The President of The SE-L Club
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Originally Posted by InsneDrmr
how would the car know how you drive?....
Their transmission controller actually adapts to your driving style when you drive in the "S" sport mode. If I drive my 330 hard the controller holds the gears longer and doesn't upshift as quickly if you let off the gas for a second. You can very clearly feel it change shift patterns to adapt to the way it's driven.
06-25-2005, 07:54 PM
#10
Originally Posted by Kevlo911
Actually the ECU is always learning, every second. There are no presets that it adjusts to. The maps are changing all the time.
wow!! i had no idea! that's really cool to know. another great reason why i
my maxima!
06-25-2005, 09:58 PM
#12
Originally Posted by Kevlo911
Maxima TCM is not that smart. 
Like I said, dissconnecting batt does not clear ECU codes.
Like I said, dissconnecting batt does not clear ECU codes.
06-26-2005, 08:02 AM
#13
I bet if you check the codes, the codes are still there
Sometimes the ECU turns the light off but the codes are still in the computer and the light will come back on in a few days.
Sometimes the ECU turns the light off but the codes are still in the computer and the light will come back on in a few days.
06-26-2005, 08:06 AM
#14
Newbie - Just Registered
Join Date: Jun 2005
Posts: 6
You can reset your maximas memory by unhooking your battery cables and hold them together, thus drainging all energy from your car, leading to a reset in your cars memory. Since you do not wish to do this, just simply make sure your + and - are not touching. You have plenty of time.
06-26-2005, 10:55 AM
#15
Originally Posted by dtm13002
You can reset your maximas memory by unhooking your battery cables and hold them together, thus drainging all energy from your car, leading to a reset in your cars memory. Since you do not wish to do this, just simply make sure your + and - are not touching. You have plenty of time.
06-26-2005, 03:45 PM
#16
Originally Posted by Kevlo911
I bet if you check the codes, the codes are still there
Sometimes the ECU turns the light off but the codes are still in the computer and the light will come back on in a few days.
Sometimes the ECU turns the light off but the codes are still in the computer and the light will come back on in a few days.
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