Nissan didn't start the transponder until 2000. If your's does have one, the bypass is simple. There's 2 ways to do it.
1. www.idatalink.com; they make interface modules for remote start to OEM. The ID piece wires in, then it's programmed by the installer. Once the programming is complete, the module simulates the key being in the ignition, but only while the remote start is in the remote start sequence (normally about 10 seconds). This goes for around $50-$75
2. A key box; Peripheral and DEI made a keybox that had a wire that wraps around the ignition cylinder. You had to physically put a working key in the box, then hide it under the dash (I always wrapped them in electrical tape and stuffed them way up under the instrument cluster). During the remote start sequence, the box with wire going to the cylinder, would simulate the key being there. These are around $25-$35.
Pricey, a little, but if you've ever had a remote start and had big changes in weather, you'll spend a few extra dollars. Im in Western KY so it's humid as can be in the summer, and in the 20's right now. When I get off work and my car is cold from sitting in the parking lot for the last 13 hours, I'll have it running 6 minutes before I get in to leave. It's nice waving and driving by everyone as they scrape their windows off. You don't have to do that if you set the defrost before you get out...
