computer reset

fdiesel · 07-13-2004, 07:56 AM

hey guys, i just installed my k &n intake and exhaust systems . can u guys tell me , how long do i have to keep my battery disconnected to reset the computer.also does it matter if i take off the postive or negative one.cuz i don't want to take the positve one off. cuz it has some kind of relay to it.all help will be appericated.

juma · 07-13-2004, 08:49 AM

just remove the negative. I think 15 minutes is enough. juma

I yield to big plat's input. 15 minutes would do it on past cars but apparently the titan is different.

juma

Big Platinum · 07-13-2004, 01:34 PM

Actually, I don't think 15 minutes is enough. I had a check engine light come on after installing exhaust and just to check I disconnected the battery for about 30 minutes and the light didn't come off. I disconnected again, but after about 2 hours I had to drive somewhere and reconnected it and still didn't go off. I then disconnected overnight and the light came off.

pciley · 07-13-2004, 05:19 PM

I did mine over night just to make sure.
As long as you disconnect the battery and then after maybe 15-30 min, just crack a door to make sure the dome light sucks out any remaining juice... when the computer is not receiving power, it resets pretty quickly.

BigRedTitan · 07-13-2004, 05:52 PM

Quote:

Originally Posted by fdiesel

cuz it has some kind of relay to it.all help will be appericated.

That box mounted to your battery is not a relay. It is your coil and distributor/rotor.

fdiesel · 07-13-2004, 06:06 PM

thanks guy one more question whats the reason for having too reset the computer after the upgrade in the engine.i dont have any lights come on in my dashboard and no service engine light no nothing.

Big Platinum · 07-13-2004, 06:43 PM

supposedly it helps the computer adjust faster to any changes to the motor. if you don't disconnect it will still learn, it will just take a little longer (about 200 mles).

BigPete · 07-14-2004, 04:11 PM

Quote:

Originally Posted by Big Platinum

supposedly it helps the computer adjust faster to any changes to the motor. if you don't disconnect it will still learn, it will just take a little longer (about 200 mles).

Big Platinum, I am not trying to give you a hard time, just trying to interpret the two different opinions that I received. I was told by an authorized Nissan service tech that there is no need to disconnect the battery and that the computer learns instantly to any changes that are made. The idea of resetting and optimization was for the computers that were used in the 80’s. Now I don’t know his qualifications other then the fact that he works for a Nissan dealer’s service department. On the other hand, maybe you have factual information for the reasons for resetting the ECU.

dandy · 07-14-2004, 04:40 PM

Quote:

Originally Posted by Big Platinum

Actually, I don't think 15 minutes is enough. I had a check engine light come on after installing exhaust and just to check I disconnected the battery for about 30 minutes and the light didn't come off. I disconnected again, but after about 2 hours I had to drive somewhere and reconnected it and still didn't go off. I then disconnected overnight and the light came off.

Hey bp it would be really useful to all of us "experts"

If you might be able to get a code from the ecu when the check engine light is on. I find it hard to believe that 15 minutes wouldn't do it. In the good ol days we use to disconnect both battery leads then short them to unload any capacitors/stored voltage. I'm not bustin balls just seeking information.

Truck41 · 07-14-2004, 04:51 PM

that mechanic is so wrong, he is out of touch. those factory parameters are set from the factory, once you make a change to that, the ecu takes notice, and begins to adjust to more air available to it, it also has to adjust to a more efficient exhaust system(less backpressure). everytime i've made a change that affects the ecu, it's taking 300-500 miles to redue its parameters. nobody knows your truck better than you. driving it everyday, let's know if all the elevators are working efficiently.

Big Platinum · 07-14-2004, 05:16 PM

Big Pete, on Nissanhelp.com, i read about the 200 mile thing. Many others here have said the same thing.

Dandy, just letting you guys know what happened, you can speculate all you want but I'm telling what really happened. After 30 minutes of my battery cable being disconnected the ECU didn't reset the trouble code. Only after all night was it cleared.

dandy · 07-20-2004, 02:11 PM

Hey bp thats weird. But its new to me so I'm learning. I can't see how it stores codes overnight maybe the cts or ats had to cool off. (insert x-file music here)