I was driving up from the city and i clicked on the od and all of a sudden the check engine light came on...i went out and just did the diag and it came up 0509 (undefined) and it came up 0115 which is Fuel INJ Sys Right bank:lean ...what is that? is it serious? can i just reset ecu and go on my merry way or do i have to take it to nissan..i dont want to take it in caus ill have to strip my mods and go back to stock for my warranty to be intact...i appreciate any swift input...thanks
http://vbxmaxima.8m.com/ecudecoder.html
that is the decoding site i used

one of your front O2 sensors is bad.. until that code shows itself.. then i can't say for sure.. if you did reset it... it might pop up next time

Diagnostic Trouble Code 0509 points to a problem with the Front Heated Oxygen Sensor, Left Bank. The left cylinder bank is also called the front bank. It is cylinders 2,4,6.

The Front Heated Oxygen Sensors are installed in the Y-pipe, the part of the exhaust system which conveys exhaust gases from the exhaust manifolds to the Catalytic Converter. There is one sensor in each branch of the Y-pipe. These sensors produce a signal which varies with the amount of oxygen in the exhaust gas, as compared to the outside air. This signal is sent to the Engine Control Module which uses it to control the fuel injection system.

DTC 0509 is detected when an excessively high voltage from the sensor is sent to the ECM. Possible causes include ...
- Harness or connectors (The sensor circuit is open or shorted.)
- a defective Front Heated Oxygen Sensor.

Diagnostic Trouble Code 0115 indicates a problem with the fuel management system on the right cylinder bank. The right bank is also called the rear bank. It is cylinders 1,3,5.

The Front Heated Oxygen Sensor for the right bank sent signals to the Engine Control Module indicating an excessively lean fuel mixture. The ECM attempted to correct this problem by directing the fuel injectors to supply more gasoline. Further signals from the Oxygen Sensor indicate that the attempt to correct the lean mixture condition was unsuccessful, and the fuel mixture continues to be too lean.

Possible causes include ...
- Intake air leaks
- Defective Front Heated Oxygen Sensor
- Fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow Sensor

You didn't say what mods you have. Please consider whether your mods may have caused these codes. Perhaps stripping them will resolve the problem.

As far as mods i have an intake and fstb...so as mentioned maybe there is a leak with the intake....and as far as..."DTC 0509 is detected when an excessively high voltage from the sensor is sent to the ECM. Possible causes include ..." could that be my wiring for my amp somehow causing a short? those are the only things i have done intake, amp,fstb (which obviously dosent do anything)...i am prob going to take out intake and take it into dealrship caus my warranty on my 98 goes through july...are the aforementioned problems serious? can i drive with it or shoiuld i wait till its repaired? thanks for your info dan B and others...

I would just take it easy.. don't over rev or anything.. i drove around with my car like that for a week till i replaced the O2 Sensor myself.. took all of 5 mins..

Now what year is your maxima.. i have heared of 95/96 owners on this forum getting the dealer to replace the O2 Sensor for free.. you may want to check it out.. if they don't want to.. its a simple install..

Signed..
And Others

The Front Strut Tower Brace is structural. It is not connected to the engine or electrical system. I doubt the FSTB could be to blame. However, you should make a visual inspection to verify that the FSTB is not rubbing on any engine compartment wiring.

I suggest you reinstall the factory intake, reset the Malfunction Indicator Lamp, and drive the car normally. If the MIL comes back and it has the same codes, you have a problem which should be fixed. It is probably a no-cost warranty repair but your warranty period is running out. Delay on your part may be costly.

I have no way of knowing just how lean your engine's fuel mixture is. If it were only slightly lean it is safe to drive. If it were severely lean it is not safe to drive. Since this is an unknown, I urge you to get this code resolved quickly. Quickly means in the next few days, not the next few weeks.

it is a 98 so it is under warranty, im going to reinstall the intake and check it out,and if there is still a problem im going to turn it into the dealership before warranty runs out.... thanks for the input guys