I had to order a replacement ignition switch/lock assembly with key for my 2004 Altima.

I transferred the electrical plugs over to the replacement to see if it would start the car before removing the old assembly.

The engine will not start as if the ECU is not accepting the new transceiver combination.

Does the computer have to be reprogrammed to accept the new combination?

Thanks.

-Lee

Perhaps you have to connect the assembly to the column to have it ground an electrical circuit. You're replacing the tumbler and key right? No reprogramming is needed for that. Can you share some photos online and post a link to those pictures here?

Also, we have the Factory Service Manuals here online under the Service Manuals link at the top of this page. Look in there for detailed instructions.

Finally, welcome to NICO Club!

Thanks for the reply.

Here is the one I purchased.....ebay.com/itm/282272860893?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It is the entire assembly that includes a new transducer and key.

I transferred the plugs over to it but the car will not start. I grounded it but still no go.

I'm wondering if a simple "ON" signal is sent to the computer, or if a new code has to be programmed into the computer AFTER the replacement assembly is connected.

I saw the service manual .pdf's for the '04 here: nicoclub.com/FSM/Altima/2004%20Altima/ but don't know which one would cover this.

I appreciate the quick reply.

Hi, all of those links are for each chapter of the FSM. The "FWD" chapter is the foreward and has the table of contents in it. The "SC" chapter seems to be starter and charger. Go through that a bit for testing and diagnoses procedures. As far as installation/ replacement, I think that must be in another chapter. But I think you have it in hand, so you don't need that instruction for nuts and bolts as much as the wiring part of it all. The "EC" chapter has lots of information about the power supply and ignition signal.

I looked at the Ebay ad and picture. Do you have three plugs plugged in? It looks like an odd black plug in the front by the key, then a black foam covered white plug near the middle, then I figure there'd be another plug in the back area for the white ignition switch circle part, but the photo doesn't show me that side... Is there a key lock removal button involved? (like you push the button to release your key all the way)

What happened is someone broke in, ripped out the key cylinder and figured they'd crank it up and drive off. But without the chipped key they were out of luck. I can start it with a screwdriver, but only by placing the chipped key close enough to the transducer to send a signal to the ECU.

Yes there are 3 plugs. The big one at the back handles the starter circuitry. The foam covered one is for the key sensor and the other one is for the transducer, which works with the micro chip in the key. I took the 3 plugs off the old assembly and plugged them in to the new assembly, but it will not start, as if the new chipped key/transducer signal is not recognized by the ECU. I don't know if there's a problem with the new key or transducer, or if the ECU needs to be reprogrammed in some way to accept the new assembly. I wanted to get a definitive answer to this so I'll know what to do next.

I'm thinking that the ignition lock assembly would just send a "GO" signal to the ECU without having to be reprogrammed, but I'm not sure.

I could not find anything in the manual that covers replacing the ignition lock assembly, but maybe I missed it.

There is not a key removal button. When the key is turned fully CCW and pulled out, a mechanism within the cylinder releases engages the steering wheel lock.

I could always just remove the old chip, tape it to the transducer and put a "Nissan" screwdriver on my key ring...

So, if you put the new key in and have the old key on the same keychain, will it start?

The new key, it's smart and has a 'chip' in it?

I hate to say it, but how about a visit to a local locksmith keyfob guy?

Yes, the Nissan keys are chipped. The new assembly will not work with the old key chip.

The way I understand this is that the small black box on the front of the assembly is a radio transceiver that sends a signal out when trying to crank. The chip in the key is tuned to that frequency and returns a good signal. So a different key is tuned to a different frequency and will not return a good signal. The same applies for a different transceiver.

I suspect that the new transceiver or chipped key has a problem and is failing to send a voltage to the computer which is not looking for a code, but simply a voltage.

Does that make sense?

What I'm going to do is replace the new transceiver with the old one, and put the old chip in the new key. Then I'll have my new keyed assembly that works with the old electronics.