Good day folks, I have a bit of an unusual problem. My girlfriend has a 2001 Maxima 3.0L. Before we started dating, she had a shop replace the main computer (supposedly). Ever since, the engine will not turn off and she(or I when I'm with her) have to pop the hood, pull the fuel system fuse then remove and replace the battery cable. Obviously, this way of doing things comes with all kinds of problems. She took it to a mechanic last weekend and he replaced the ignition switch but it did nothing to solve that particular problem. We can't get the car smogged since the computer is reset every time she turns to car off. We had the IAC replaced at the same time as the switch which now keeps any codes from coming up.

Other 'weird' issues that may or may not be related. The speedometer will only go to 40-45 mph no matter how fast the car is actually going. The wipers no longer work(ever since the computer change). The head unit controls work at the steering wheel but not usually at the console.

Thanks.

 

The fuse should do the trick. Also, there's a fuse inside the car that controls the fuel pump, no need to pop the hood or remove the battery cable.

 

I am always marginally confused by these types of posts. You had a shop do a job, they messed something up (from how you are wording it, that seems to be the case), and you didn't take the car back to them and have them fix it?

If they replaced the computer then blammo all these issues, seems pretty obvious that they installed the wrong computer or it's not programmed, etc, etc.

Unless there is a few key components from your story missing.

 

Well, the work was done by a shop (that no longer exists, no surprise) and it happened well before we were dating. Otherwise, yes, we would have brought it back and had them fix it. As for the fuse issue, killing the fuel system does indeed stop the engine but it does not turn the car 'off'. The dash lights and computer are still 'on' until the power is pulled. My girlfriend is completely and utterly clueless about cars hence her getting hosed at the mechanic. In fact we just changed the IAC and it turns out the reason it wasn't 'working' is because the previous shop stripped the aluminum throttle body housing, jamming a screw and not allowing the IAC to fully seat. And yes, they installed it that way and gave it back to my girlfriend.

 

ouch that sucks. well you sir have an electrical mess on your hands.
www.nicoclub.com/FSM/

 

Do 00-01 still have NATS/IMMO? If so, I bet the mechanic didnt actually replace the ignition switch. The computer being wrong is the real story here though

 

Yes^, and yes, I would be very shocked if this ISN"T a computer problem

 

scrap the car

 

The switch was just replaced by a mechanic Last weekend, not the original shop.

 

Maybe the Engine Control Module (ECM) has a bad power relay. The ECM relay is under the hood in front of the battery. The cover on the box is labeled ENGINE CONTROL. The relay is tan colored and you can swap it with the tan relay that is above it or next to it.

Give that a try.

 

did they reprogram the NATS as part of that? If they dont have a consult tool at this shop then I doubt they replaced the switch.

 

You don't need to re-program NATS when the ignition switch is replaced. The NATS module is a separate critter, not interconnected with the ignition switch.

 

Your car wouldn't start if Nats wasn't programmed. Sounds like you have a possible ECM shorted or a cross short somewhere in your electrical. With the way they installed the IAC anythings possible.

 

you sure about that? The FSM disagrees, but it might just be being vague overly generalized it when it says "NVIS (NATS) immobilizer control unit (IMMU) located in the ignition key cylinder"

my point was that since (IF?) the NATS would need to be reprogrammed and its extremely rare for a small mechanic to have a CONSULT tool, it probably wasnt replaced at all.

 

I am sure about that. The NATS unit is a separate, independent unit mounted next to the ignition key cylinder, in the front of the car direction. It definitely is not in the ignition key cylinder. The FSM has its share of errors and you have found another one. If you skip ahead to page 375, there is a drawing of the NATS unit and the ignition key cylinder.

Then there is the ignition switch. It is a separate unit that has a metal tang from the ignition key cylinder running through it that turns when you turn the ignition key. 2 screws and it comes off the back side of the ignition key cylinder.