I just bought a 99 Maxima Auto with the common no start/NATS, Security light stays on. Bought it from a friend who happen to buy a 6th gen and had this 4th sitting due to the Nats problem and didnt bother fixing it. Well $300 later, its mine and decided to give it a go, car is clean inside and out and comes with some bits and goodies, coil overs and intake still in their box.

Well now where can i start so i can get this thing started again? I have gone through all the steps, removing battery and reconnecting, keeping the key in for an hour, looked at the manual for info, just to get it started but no hope. I did have two locksmiths come and try to connect and reprogram the keys but both reported their computers would not connect both OBD2 or Consult port.

Now my only two options are 95-97 ECU swap but no writeups on automatic tranny Max or taking it to the stealership.

Could i just replace the nats module myself , and take it to the stealership and it be fixed? Where could i get one?

 

To program keys on the 99, the locksmith has to use the CONSULT connector by the fuse panel, not the OBD II connector. The consult connector is not the same as the OBD connector and therefore requires a different cable. I don't understand why the locksmiths could not connect.

As in any problem there are always several causes of the problem. The NATS system consists of 2 modules. The antenna module is in the steering column by the ignition switch to pick up the signal from the key. The other module is the "brains" of this dumb system and it is under the dash between the steering column and the center console.

See drawing on page 295 in this link:
http://boredmder.com/FSMs/Nissan/Maxima/1999/EL.pdf

You could try finding these modules in a junkyard car, either a 99 Maxima or Infiniti I30. Then you would have to have the keys re-programmed, either at a dealer or another locksmith.

 

You should be able to connect anyway to pull a NATS code. I had a similar issue on this 01 and turned out it was the connection harness. I didn't have the lever all the way back when I plugged it in.
I checked continuity through the ECU where the pins meet the circuit board.