# Engine Light Still On (Needs Reset)



## alternate8 (Feb 7, 2004)

I have a *1996 Nissan Sentra GXE 1.6* and just yesterday I had to replace the _alternator _ and the _battery_. The battery, when tested, only showed 10.5v. Anyway, I figured that must have been the problem with the engine light being on, but when all was said and done and I replaced both the alternator and the battery the engine light is still on.

I'd like to know if there is any way that I can reset the computer myself so that the light goes off. Our mechanic, who is a friend of the family, said to reset the computer all I would need to do is touch the negative and positive battery cables together. This didn't work, of course, and I personally don't see how it would. He also told me that if I were to do that and the light to still be on that then there is another problem with one of the engine components. The light is still on after touching cables, though, and I really don't think there is another problem. I've checked the fuses and they are all fine.

I really don't feel like forking over money for a simple reset if there is a way for me to do it myself. Any suggestions?

Thanks
-Dave


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## psuLemon (Apr 23, 2003)

do you have any work done to your car... i could be almost anything, if one of your O2 sensors is burned out, it would read wrong, why dont you go to like auto zone and get a diagnositic to find out the code


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## alternate8 (Feb 7, 2004)

Yeah, I actually just got off of the phone with Advance Auto Parts b/c AZone is still closed and the guy there told me that I can't unhook the battery and expect the chip to reset b/c the 96 models and above were switched over to the OSB2. The OSB1 models you can actually unhook the battery and the chip would reset.

When AZone opens I'm gonna head over there and have them run a diag. and reset to see if that fixes the problem.

As far as work being done on it, like I mentioned, I replaced both the alternator and the battery b/c both were shot. The light had only been on for 3 days until the car would refuse to turn over and/or fail altogether. So I'm assuming the battery and/or the alternator were the reasons for the yellow engine light coming on. Now I just want it reset. I'm just kinda wondering if there's a way that your "average Joe" could reset it w/o needing to head to AZone or a dealership.

Thanks for your quick reply.


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## psuLemon (Apr 23, 2003)

you can reset it by two ways, you the obdII moduler and reset it that way or you unhook the battery overnight...

by work i meant aftermarket stuff.. like header etc...


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## alternate8 (Feb 7, 2004)

Well, I just got back from AZone and I got two errors
*P0400 - EGR Flow Malfunction
P0130 - O2 Sensor Malfunction*

Now, I'm guessing the O2 Sensor is the oxygen sensor, but I have no idea what the EGR Flow is.

I've got a few questions about this:

1) What is the O2 Sensor?
2) What is the EGR Flow?
3) If I can't afford to fix either will this cause problems soon?
I work 40 miles away and use this car to commute to work and back to save on gas money.
4) About how much would both the O2 Sensor and the EGR Flow cost me to buy?
I'm going to look this up at Advance Auto Parts' website.
5) Are both of these things something I can replace myself w/o having to go to a mechanic?
The only things I've ever worked on with a vehicle is filters, replaced an alternator, radiator, oil changes and a few other minor things such as a battery, etc. Would I have the ability to replace these 2 malfunctioning parts?

Thanks for the help
-Dave


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## psuLemon (Apr 23, 2003)

your O2 probably went back,i believethey are like 60-80 to replace, i could be wrong, the egr is your exhaust gas recircualation, you prolly just have to get the egr system cleaned. they wont really affect your driving cuz you car will be in safe mode... the O2 measures your air/fuel ratios, while the egr is self explanitory....


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## alternate8 (Feb 7, 2004)

I've seen you guys here at the forums talking about Safe Mode. What exactly is that and does it hurt to always be driving is Safe Mode?

Yeah, I checked out prices at www.partsamerica.com and see that an O2 Sensor can cost anywhere from 17.99$ - 90$ depending on how many thousand miles it is good for. As for the EGR Flow I was wondering about that b/c when I did the search it came up with a few different things such as:

*Air Conditioning* 
EGR Valve Control Switch 

*Emissions * 
EGR Bleed Filter 
EGR Vacuum Solenoid 
EGR Valve
EGR Valve Gasket 

*Gaskets * 
EGR Valve Gasket 

*Sensors * 
Air Flow Meter/Mass Air Sensor
EGR Valve Position Sensor 

*Switches * 
EGR Time Delay Switch 


I was wondering which one exactly is the one that the error was for. Again, what exactly is Safe Mode and does it hurt to always be driving is Safe Mode?


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## psuLemon (Apr 23, 2003)

i believe if you do a search, you will be able to find how to clean the egr system out.. both aren't that hard to do if you are mechanically inclined


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## psuLemon (Apr 23, 2003)

clean out your egr valvle and rails and that should help.. safe mode is just like a computer mode that wont allow for major problems to occur


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## alternate8 (Feb 7, 2004)

Yeah, thanks, man. I just have to find out where exactly both are located.
Thanks for your information and help, *psulemon*!


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## psuLemon (Apr 23, 2003)

anytime


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## alternate8 (Feb 7, 2004)

Does anyone know of a good site that explains the whereabouts of both (or just one of each) the O2 Sensor and the EGR Flow Valve? Not just location, but how to clean and replace, etc. I can do most of it if I could just find out where the heck these two parts are. I noticed that there's a _Sensor located in front manifold exhaust pipe before catalyst_ and also a _Downstream sensor, after catalyst_. Should i replace one or both?

Anyway, I might be coming back and forth to this topic until I get these things resolved.


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## psuLemon (Apr 23, 2003)

probably the best bet would to buy a haynes manual, for the O2, i believe you can get them tested out. or you can unbolt them, and see if either are all messed up, covered with black stuff or anything


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## alternate8 (Feb 7, 2004)

I found a good site that explains what all the codes mean in an OBD2 system: http://www.jimbennett.net/ECU.htm

Then here is another page that shows the EGR Valve in a 1995 Maxima. I'm wondering if that is where it will be on my 1996 Nissan Sentra GXe. Also, is the way he explains to clean it the best way to go about it? He actually uses a clotheshanger to pick the carbon out of it and then a vaccuum to ensure that floating carbon is removed.

I saw elsewhere that someone was charged 1000$ to get their EGR Valve replaced.

BBL...gotta jet


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## alternate8 (Feb 7, 2004)

Yeah, I've been wanting ot buy a Haynes manual, or even a Chilton's manual, not sure which one is better.

I dunno, I'm still researching this crap out, I'm trying to save as much money as I can b/c we already spent a shitload on our '91 Explorer.


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## psuLemon (Apr 23, 2003)

a clothes hanger and a nice soft cloth will do perfect, with the manuels, they are bout the same, if you want and have IM my sn is psulemon27


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## alternate8 (Feb 7, 2004)

psulemon said:


> a clothes hanger and a nice soft cloth will do perfect, with the manuels, they are bout the same, if you want and have IM my sn is psulemon27



I don't IM anymore but you can email me at [email protected] :hal:


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## alternate8 (Feb 7, 2004)

Hey, if I took a digital picture of under my hood do you think you could point out kinda where the damn EGR Flow Valve is located? You know, like cirlce it out in photoshop or something? You're tempting me to get Trillian again.


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## psuLemon (Apr 23, 2003)

i dont have photoshop or anything. but its directly south of the cai and tb if you follow your egr tube off the header, it should pretty much point you in the place


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## alternate8 (Feb 7, 2004)

Alright, I did a google image search of an EGR Flow Valve and then went out to the Nissan to try to see if I saw anything similar, and I think I may have found it, although I'm not sure. There's two wire connector plugs hooked up to the black non-metal part....the gasket looks good. I'm downloading Trillian and then going to activate a AIM account and add you to my buddy list. I'm also gonna take a pic of what I think the EGR Valve is with my crappy digital camera and send it to you in AIM. Does that sound cool?

I appreciate any help for you could be saving me money on labor that I could end up doing by myself


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## psuLemon (Apr 23, 2003)

sounds good to me, if im not on cuz i get off work at 3 then i have to go suit shopping for my internship, just send an email to [email protected]


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## philb00 (May 17, 2008)

hi i got same s-box - 96 sentra gxe has the 0400 code too.. bout 120k miles

so did ya fix this yaself or pay shop to do it ?


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## rogoman (Dec 16, 2004)

alternate8 said:


> Well, I just got back from AZone and I got two errors
> *P0400 - EGR Flow Malfunction*
> *P0130 - O2 Sensor Malfunction*
> 
> ...


P0130 is the front heated O2 sensor malfunction. The most likely causes are the sensor itself or the electrical harness connector. A front heated O2 sensor can cost over $100. Call a Nissan dealer for a price then call some auto parts stores to get a price comparison.

P0400 is a problem in the EGR system. It could be one several items.
- EGR valve sticking
- Cracked hose(s)
- Bad EGR solenoid
- Electrical harness connectors


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