Last month the light came on while I was driving the car with the fuel
level down to probaly 1 gal or even less. I'd never let that happen
before and was hoping that the light would go away with a full tank.

The car has 70K miles, engine has never been repaired or serviced
other than fluid and filter changes at normal intervals.

Well the light did not go out when the tank was filled. I had the code
checked and it read as an O2 sensor, had the light reset and it came
on again within 20 miles driving.

The thing is, the engine is running super strong, no issues at all, in
fact it's getting better gas mileage this year than it ever has (a 2
mpg improvement, noticeable about 3-4 months before the SES issue
began).

I've read so many horror stories about attempts to correct an SES with
ensuing major engine screwups that I'm inclined to use the 1 inch
square of electrical tape correction method.

Can anyone comment?

Doghouse Riley wrote:
<snip>
1. There are at least 3 O2 sensors in your Maxima. The code stored in
the ECU (set SES light) will point you to the exact sensor. So do you
happen to know what the code was?

Replace the faulty O2 sensor and keep driving.

To avoid any so-called horror stories,
1. stick to quality parts
2. stick to a competent mechanic or dealer
3. don't expect any shop to do the work for next-to-nothing
4. educate yourself about the problem (as you are doing) so that you
know when you've found a shop that's trying to pull the wool over your
eyes.

Good luck!
Nirav

What is your error code? On following error codes, manual suggests connector/harness problem. (The O2 signal is very easily warped as its signal level is so minuscle, very little is needed to kill it... see page14 on link below.)

Text from FSM page EC-249, Maxima 2k2, for error codes DTC P0138, P0158
"Component Description: The heated oxygen sensor 2, after three way catalyst, monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions.
---> Under normal conditions the heated oxygen sensor 2 is not used
for engine control operation."

Catch 22 BUT-NOTE: error light will be ON if signal not ok.

Check out for more, clicking via top left 'Favorite Links' ... see link below.


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Wiikinki
www.cardomain.com/ride/748507/1
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