TSB's - 2002 GLE

It's an emissions part, it's covered by law for 7/70 and I believe to

Not true. The 8/80 federal emissions warranty (it's not 7/70) only covers the ECU and catalytic converter. O2 sensors fall under Nissan's 3/36 new car warranty. It's all spelled out in the warranty manual.

As for ssnazzy9's question, part of the TSB (reflashing the ECU) would fall under the emissions warranty, but not the replacement of the O2 sensor(s). P0138 points to a problem with a rear O2 sensor and those sensors are used to help monitor the efficiency of the catalyst system. Unlike the front sensors, they don't affect drivability and nothing will be damaged if they're not working correctly. You may be able to get the dealer to simply reflash the ECU under warranty and hope that the light won't come back on after that. If it does, you'll have to bite the bullet and replace it. If you want to save some money, you can replace it yourself. It's the sensor on the front of the pre-cat (white connector).

I have a similar problem. Just picked up a used 2002 GLE with 72k miles. Less than a week after picking it up from dealer, the power window on the right side had its recoil sensor automatically activate if I pulled it up using the auto window up. Minor problem, so the dealer was able to cover it completely under the Lemon Law, but when I picked up the car after the dealer fixed the window problem, I noticed that the Check Engine llight came on.

I had the code checked out with a local mechanic, who said the error code was P0138, and the problem was with the Bank1 Oxygen sensor being stuck at 9Volts. I told the dealer about this, who said he'd cover it with the Massachusetts $100 deductible, but a day before I was supposed to drop off the car, the Check Engine light disappeared! How do I know if the O2 sensors are really busted, and more importantly, how can I get the CheckEngine light to come up again, so I can get the dealer to cover the 02 sensors under the lemon law?

I have another 1100 miles till I'm covered by the lemon law, which is not a long time.

Even though the light is out, the code is still set. The dealer can read it. Not to worry, it will come back on right after your warranty expires either way! :-)

I'm worried that the dealer will refuse to fix it, since the Check Engine light is not on anymore. How does the ECU work with stuff like this? why would the Check Engine light disappear and still show the last error code?

Because the failure is intermittant. Could be something loose or more likely a marginal component. If it came on once, it will be back.