Today I was driving on a road in 5th gear doing about 50 and all of a sudden the Service Engine Soon light went on. The car feels no different at all and nothing is wrong with it. I'm going to AutoZone when I get out of work to get the code read. Anyone know why the SES light randomly went on? When I get the code, does anyone know where I can find out what the code means? Thanks.

EDIT: I have a 5spd and it only has 38,000 miles with 1,000 on a new clutch.

 

I would just reset the ECU. If something is really wrong, it'll come back on. Look around on the org for a "how-to".

 

Did you check to make sure your gas cap was on all the way...................I've seen it happen.

 

90% of the time.

If that's not it go to autozone. I don't suggest simply resetting it without finding out first. It's free after all.

 

Thanks, I'll check the gas cap and re-set it.

 

When I reset the ECU, do I need to take off both battery wires, or just one? I took off the ground for about an hour and it didn't do anything

 

thats weird to reset my ecu, i just disconnect the negative terminal and all it takes me is like 30 min.....presto bam oooo done.

 

My SES light came on around 15K miles...took it to the dealer and it turned out to be 2 Oxygen sensors. Thank god it was under warranty.

 

Do we have to always depend on autozone for the darn SES light readout??? in my previous GM and Ford vehicles I could get the codes myself by jumping a couple of wires and watching the light blink out the codes
How do we get our own codes in the MAximas???

 

Went to AutoZone, scanned code #0420. He said it was an O2 sensor or something like that. After he scanned it, the SES light went away. Should I still bring it to the dealer to get the sensors replaced?

 

If the code is still there, they may repalce them. But if the code cleared itself or the light isn't on, you may have trouble getting nissan to fix it.

 

mine just came on two days ago as well.... this seems like a common problem for nissan b/c my parent's Quest had the same problem

 

you reset the ecu...... from the ecu

 

There is a way to make it flash the code back at you, but I just think it's easier to drive down to autozone and they print it out for you and everything.

Also you can reset the ECU without disconnecting the battery.

(if someone can tell me where this image originally came from, I would like to know so I can give credit each time I post it.)

 

P0420 = Catalyst System Efficiency Below Threshold (Bank 1)
If its your O2 sensors, I just replaced one of mine and its not hard to do. I decoded your code at:
http://www.iequus.com/obd_def.asp
If you live in CA, I believe you are still under warranty (<50k), but if not, you might be out of warranty for emmisions stuff. Call your dealer.

 

If it comes back on, go back to Autozone. Make sure it is the same problem. There is a TSB for this causing a false error. They reprogram the ECU at the dealer. Otherwise, it could also be the MAF, catalytic converter or O2 sensor. The ECU reprogram and cat are covered under your emissions warranty. I think this is a 60 or 80k mile warranty. Check out studman's website for a list of TSBs. I don't happen to have the link handy right now.

I just had this problem and had them reprogrammed my ECU. Hasn't come back since. And yeah, it just turned on while I was driving with absolutely no change in performance of the car. This error is an emissions problem. It won't affect the way your car drives, unless it is the MAF, in which case, your car will probably run rough, hesitate or even stall.

 

Car runs fine and the light has gone away after it was scanned. If it comes back on I'm going to the dealer about it.

 

Will this work for a 01 Maxima. That diagram is for an 02.