service engine soon light

[nflxterra]

hello all,
i have a 2001 xterra xe 4x4 with all three pkgs,,, i've owner her since she had 3 miles on her. today is the third time i have had the "service engine soon" light come on, i have 34k. 1st time it happened after i filled up with gas for the first time. 2nd time after cleaning the engine "with engine running" and dist. and a few wires covered. it appeared the next day, but i filled up with gas that day too. that was 15k miles ago and the last time i saw it. both times i took it too the dealership and they said 1st time " there is a bad sensor in the fuel system we need to replace the fuel tank" i said reset the sensor and we'll think about it. to me i'm thinking the dealership wants some money from nissan. 2nd time they said "the gas cap wasnt closed tightly enough" now this i could believe. today i didn't fill up with gas but had washed the outside of the truck, not under the hood, i disconnected the battery, after noticing the light come on, for about an hour checked the gas cap opened it and put it back on till it clicked, connected battery, and miracle of miracles the light was gone. does anybody have any clue about this, has it happened to anyone you know. my x seems to run fine nothing different. thanks

[Schludwiller]

There is a problem with the fuel sending unit wires corroding on some Xterras (so much they're on national backorder apprently). However you don't need to replace the gas tank. The unit is under your passenger rear seat (under a metal flap), so it's accessible. Some people have done the repair themselves if you're comfortable with that.

If you disconnect the battery you're going to clear ALL warning lights regardless, so it would clear a code that's related to your sending unit as well.

Your truck might be running right, but be aware if the sending unit is malfunctioning, there is a good possibility that in the near future it will stop running until the unit is replaced.

I would be warry of a dealer who says you need to replace the whole tank though.

[aero_steve]

I've had bad luck with check engine light, at least a dozen occurances in the 14 months I've had my 2002. The first couple I took it in, I been ignoring it since and the light has always gone away by itself or after diconnecting the battery. To me it engine generates faults way too easily.

1) Loose vacuum hose on way home from dealer
2) Purge Control Valve from over filling the tank first month
3) Mud someplace it shouldn't have been, cleared itself (3 times)
4) Air intake came off MAF sensor after engine mount broke and engine went into failsafe. Cleared itself once everything was put back together
5) Tree took out backup lights and the light came on. I had done a lazy wiring job and it blew the A/T Cont fuse whenever it was put in reverse. Without this fuse the truck wouldn't start.
6) Almost every time I wash under the hood I get the light. I wait a couple days and disconnect the battery to clear it. The code has been for an O2 sensor when I've checked it. (every couple of months)

[aero_steve]

Originally posted by Schludwiller
I would be warry of a dealer who says you need to replace the whole tank though.

I think that was the common fix for the purge control valve fault code. In 2002 the tank design was changed so that the valve could be replaced without replacing the whole tank.

[nflxterra]

thanks for the heads up on the fuel sending unit, i'll ask a different dealer here in town, see what they have to say. this was my first post im sorry i did not realize i put it in the owner's rig section, sorry about that. yeah i was a little aprehensive to having them replace a whole fuel tank on the truck for just a warning light coming on? four people that i know have an xterra but none a 4 wheel drive so i didn't know if there was some other reason, ill be asking this saturday.

[Schludwiller]

Here's a good thread on some of the problem. Should help you when you talk to the dealer.

http://voy.com/14174/3/

[ChuckH]

I don't think the actual fuel sending unit has anything to do with the light. The light is strictly emissions related and all the fuel sending unit does is operate the fuel guage and work as a wiring harness for the fuel pump.

Not only that, but when the fuel sending unit bites it there is no warning.

THe light could come on if the fuel tank has some sort of pressure problem, or lack thereof, or it could be the gas cap or an oxygen sensor, or some other emissions related item. Bad gas and/or a misfire, or a disconnected spark plug can cause it too.

[nflxterra]

i'm going with the gas cap and pressure theory, plugs are snug engine idles nice no wires disconnected that i can see no vacumn lines either matter of fact the only thing wrong was that light coming on. oh well. i don't know about the corrosion, the first time it came on was the first time i actually filled it up, truck was made in june 2001, i bought it in july 2001 so i don't think it would corrode that quick, but you never know.

[X-Factor]

I bought an 03 X and have taken it back to the dealer 3 times for the SES light on. The first time the sensor told them that the engine was starting to run hot. Coolant level and in dash guages were fine. We reset and left the lot. The second and third times were for the gas cap, (some sort of pressure deal). They replaced the gas cap and that is where we are now. Both warnings for the gas cap came after we burned over a half tank of gas. (5-6 days easy driving to work and back) We only have 730 miles on it and frustrated is not the word to use. Anyone else with an 03 X having the same problems early on.

[nflxterra]

have the 01 but had this problem several times, all i can say is make sure you tighten the gas cap till it clicks about 3 times or so and if it does happen again instead of going to the dealer, remove your positive battery cable and wrap it in a rag or towel or something set it aside for about an hour or so then reconnect it, the light should be reset. if not then i would go to the dealer. i also have noticed that it would come on more frequently by getting gas a particular gas station, coincidence maybe? but 5 out of the 8 times it was with Gate gas stations down here in Florida all i could think of was the octane was lower than what was posted, but it seems to have gone away now. good luck and try to write down a list of where you got gas, did you tighten the cap, how much gas was left in tank when you filled up, etc.

[Schludwiller]

I buy Chevron. Texaco in a pinch. There is some really crap gas out there. Arco is one, and any bubba gas station you don't recognize.

[nflxterra]

see that's what i'm starting to think, that is this sensor being tripped by octane levels lower than the posted 87 like maybe 83-86 or is there water in the gas. anyways that's about all i can think of to trip this sensor at a certain gas station.

[msxterra]

I'm not too sure if the fuel system has anything to do with the light coming on. This past February, I had to replace my fuel sending unit and the service engine light "NEVER" came on. After the unit was replaced, about 4 or 5 days later the light then came on because of my gas tank cap not being tight. Then light goes away. Now, here it is June, the light is back on and I took it in and they couldn't find anything :confused

You might be right about the fuel. I did fuel up at a different station than I use to. Hmmm. Interest. I will keep a close watch on that.

[hobbes69]

Is there a way to check this code without a code reader? All I needed was a paperclip for my past to trucks, (85 GMC S15, 89 Chevy S-10 Blazer).

As far as water in the gas tank, I have been using the silver bottle STP stuff for years. It removes water and cleans the fuel system/injectors. I just measured my mileage a few tanks after using the STP stuff with a mixture of city/hwy, and its up to 17.5 MPG, the highest its ever been for me.

Richard