Sentra computer out?

My 2000 Sentra check engine light came on, code said idle control.
The dealer installed a new one and said the computer (ecm) was also
bad so I got a used one, they installed it and everyting was ok.
That was Nov. now the same code again and the dealer
is saying that the computer is bad again. They want $800.00.
The car runs great except a little high on the idle.
Anyone have a experience like this? Help!

What code are you throwing (number)? Before I would pay those jerks at the dealer, I would try cleaning your IACV (Idle Air Control Valve). This is a very common problem on our and all cars, where carbon builds up on the spring and causes it to stick. It's very simple to do, and heres a link w/ pics. http://www.nissanforums.com/showpost.php?p=786899&postcount=8 . I would give it a good cleaning, clear the codes, and drive it around and see if it throws the code again. Either way, I don't think it is the ECU, and would take it to somewhere else if the code comes back. And cleaning the carbon off the IACV and Throttle Body is something that should be done annually.

Oh and you can adjust the idle, there is a screw on the IACV under a black cap, just unplug the TPS (Throttle Position Sensor) and then screw it I believe clockwise to lower the idle, then plug the TPS back in.

Thanks a lot! I think the code was 0505, could be
wrong, but I did read the code myself and looked it
up. It was for the IAC valve. I just find it hard to
believe this "new" one is bad too. Especially in just
a couple of months. I'll sure try and adjust the idle,
that may very well take care of it. Thanks a lot!

Thanks a lot! I think the code was 0505, could be
wrong, but I did read the code myself and looked it
up. It was for the IAC valve. I just find it hard to
believe this "new" one is bad too. Especially in just
a couple of months. I'll sure try and adjust the idle,
that may very well take care of it. Thanks a lot!

Are you sure it is 0505, because at least on my sentra that means that everything is ok. If you have an autozone they will check the the codes for free. Just ask them to do an OBDII test on your car, that will give you the right code for sure. Either way still clean out your IACV, because it will give you better throttle response anyway.

No, I'm not sure of the actual number of the code.
But I am sure it was the idle control valve.
It was read two different times.

No, I'm not sure of the actual number of the code.
But I am sure it was the idle control valve.
It was read two different times.

Wait...if you are not sure of the number, how do you know it is for the IACV?

Because at the time I pulled the code myself, wrote
it down and checked the book for the code.
I don't remember the number but I sure remember
what it said it was.
The time before that someone else read it and said the same thing.
So I'm pretty sure of the item, just not the number.

Because at the time I pulled the code myself, wrote
it down and checked the book for the code.
I don't remember the number but I sure remember
what it said it was.
The time before that someone else read it and said the same thing.
So I'm pretty sure of the item, just not the number.

Ok then just clean it with the directions I gave you, because that being stuck can throw codes.

OK, thanks, I mean really, thanks a lot.
I plan on checking it out, it's my daughters car so I don't know
how soon I can get it. Do you think the high idle can trigger a code?
I'm gonna try and set it down.
This valve is only 3 months old, can it get dirty that quick?
I know, it depends on how you drive. My daughter has a lead foot.
She has two speeds, stop and full throttle!
I am trying to talk her into driving it the next time she takes one
of her trips to her boyfriends home, Chicago, which is about 6 hrs
from here. That would probably do it a lot of good.

Well I took the idle control valve off and it was super clean, looked brand new.
There is nowhere to adjust anything on it.
It's a sealed plastic case that has no plugs.

Well I took the idle control valve off and it was super clean, looked brand new.
There is nowhere to adjust anything on it.
It's a sealed plastic case that has no plugs.

Hmmm...if the spring inside is not sticking or gunked up, I am at a loss...if the car is running fine, I would just not worry about the light, as the sensor might be bad, but if it really worries you, I would take it to a different mechanic and get a second opinion, since I still feel the first one is ripping you off. I can only say maybe adjust the idle, spec is at 650 +/-50 for manual, and 750 +/-50 for auto (I think for auto, but I have a manual, so look on the bottom of your hood). I'm not sure if this will throw a code or not by having a high idle, but now your guess is as good as mine. Good Luck.

I need to figure out how to adjust the idle.
So far I haven't been able to.

I need to figure out how to adjust the idle.
So far I haven't been able to.

You need to take off the Throttle Positional Sensor (TPS) and I made a mistake earlier, on your years I think the black cap is on the throttle body, where on mine it is on the IACV, so take off the black cap and there should be screw behind it. Just take that off and turn the screw to lower or raise the idle. Then plug the TPS back in and your good to go.