Hey guys, I'm new to this site but love the posts I've been reading so far.Most people seem exceedingly knowledgeable about their nissans. I was always a Honda guy but fell in love with the torque of a VQ35de. I have a 2002 Maxima SE with 268km. Just bought the car and it runs pretty well for the mileage. The few problems I am having are Im getting the codes- P0031, P0051 and P0037. Doing some research they seem to be the O2 sensors on three different locations on each header. They are super expensive and I was wondering would it be vital to the car's performance and reliability if I got these sensors because I know it helps with gas mileage.

A second issue I am having is a crazy fuel gauge. It doesnt read the proper amount of fuel and as a result I broke down in the middle of traffic in a very busy area with no place to park FML. I heard about something called a fuel sending unit which is a floating device in the tank. Is there anyway to troubleshoot all of these issues before breaking it down and pulling out some money? Any help on resolving these matter would be appreciated. Thanks guys.

 

If the o2 sensor is bad the car will compensate for the too rich/too lean problem and lead to decreased gas mileage and decreased performance. I have owned Maximas my how life and you will find out that your check engine light will stay on for exhaust reasons ( cant speak on behalf of other but its been that way for me, prolly cause I drive my car like a bat outta hell but they have always run so good. love the VQ motor). My last maxima had a check engine light on for 70K miles it was just A SINGLE 02 sensor in this scenario but performance seemed to not be affected, car ran great. I would suggest replacing them in your scenario due to the fact these what you think are 02 sensor issues could be indeed something more serious. I would start with the cheapest one and test drive to see if that specific error goes away and repeat..therefore making sure you don't have faulty harness/ other issues going on besides the sensor itself. I am no expert by any means but these are just my opinions/ suggestions and what I have experienced since my dad has worked for Nissan parts for about 25 years. hope this helps some and once again these are solely suggestions.

 

Ur fuel problem is not the sending unit, its the gauge cluster, ebay is ur answer and its a hit or miss. there is a procedure to be 100% sure u unplug the fuel pump and put a resistor in there and u match up ur reading on the gauge to the resistors value yatta yatta yatta, its somewhere on the forum theres a chart search for it.Yea o2's are expensive rockauto has decent prices but still expensive. Heard some ppl talking about the brand NTK for o2's read up on them see if theyre any good.

 

Umm, that seems complicated. The FSM has a self diagnostic procedure for the cluster.

 

Thanks guys! I will take a closer look and replace what is needed. I'm hoping it isnt a serious problem other than the cluster and o2 sensors because you're right it could possibly be a bigger problem. I'll keep you guys posted!

Is it possible for the self diagnostic procedure to have failed? I mean if the problem is as simple as the gauge like you guys say its a hit or miss right?

 

If you can successfully enter the diagnostic mode and it reads different than the manual describes then you have a bad cluster. Otherwise your problem lies elsewhere. The procedure is as follows.

Meter/Gauge Operation and Odo/Trip Meter
Segment Check in Diagnosis Mode

DIAGNOSIS FUNCTION
-Odo/trip meter segment can be checked in diagnosis mode.
-Meters/gauges can be checked in diagnosis mode.

HOW TO ALTERNATE DIAGNOSIS MODE
1. Turn ignition switch to ON and change odo/trip meter to “TRIP”.
2. Turn ignition switch to OFF.
3. Turn ignition switch to ON when pushing odo/trip meter switch.
4. Release odo/trip meter switch 1 second after ignition switch is
turned ON.
5. Push odo/trip meter switch more than three times within 7
seconds.
6. All odo/trip meter segments should be turned on.
NOTE:
If some segments are not turned on, unified meter control unit
assembly should be replaced.
At this point, the unified control meter is turned to diagnosis
mode.
7. Push odo/trip meter switch. Indication of each meter/gauge
should be as shown below during pushing odo/trip meter switch
if it is not malfunctioning.
NOTE:
It takes about a few seconds for indication of fuel gauge and water
temperature gauge to become stable.

 

Awesome dude! Thanks! I'll go out now and give it a shot!

 

Hey Guys just an update. I tried for the last few days to run the diagnosis mode but it wouldnt work! It seems everybody else does it easily but I'm guessing this could also mean the cluster is bad because it wont allow me to enter diagnosis mode or I'm doing something wrong lol. Feel like quiet a Noob. When you say change the odo/trip to "TRIP" what does that entitle specifically?( Never had to face this issue with a Honda :/)Because I did almost everything from cut the switch on and press the trip switch until it clears then cut the ignition off then cut it back on whilst holding the trip for one second like the instructions said. The cluster needles didnt move like they were suppose to. Bare with me guys. Thanks Max fam.

 

I just tried this on my Max (as I've never actually done it before) and here's what I did exactly.

1. Turn on the ignition and make sure the trip meter is on Trip A. Turn off the ignition.

2. Press and hold the trip button. Turn on the ignition and release the trip button after 1 second.

3. Press the trip button 3 times within the next 7 seconds.

4. You should now be in diagnostics mode. I had all of the segments on the trip meter (left side) were lit up. The meter on the right was flashing dte.

5. Press and hold the trip meter button. Now your gauges should move to the positions shown in the picture above. You may have to wait a few for them to level out...they bounced on me for a second. Release the button and all gauges should return to zero.

6. Turn off ignition to exit diagnostics mode.

*Edit - This is the trip button on the cluster btw NOT the mode button on the steering wheel.