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Discussion Starter · #1 ·
About three days ago, I hopped into our 2006 LJ Rubi and noticed the engine light came in as soon as I started her up. My husband said it was not there a few hours prior. I listened carefully, revved the engine, drove around the block and everything seemed normal. My hubby's stepdad (mechanic) said to start with basic possibilities: 1) check to make sure the gas cover is on correctly. He said it can commonly cause the engine light to light up if it isn't in place on a Jeep. 2) It may have to do with emissions. He suggested using Seafoam in the gas tank as well as the fuel line.

We drove the LJ for two days with the engine light on (it's our only vehicle right now). And without using the Seafoam we bought, it went away. Haven't seen it all day. Any ideas as to what may have caused it? Has anyone else encountered this gas cover issue before? We're thinking that may have been the issue, as we did fill up the tank yesterday (thereby removing and replacing the cover), but I'd like to hear from the Wrangler community about common problems you've encountered. Thanks!
 

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Gas cap would do it. i have had the same on mine, when I lived in NJ, you can't pump your own gas. The attendants wouldn't put the cap on right and in a couple of hours I would get the light. Crank it down...:thumb:
 

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ParaRigger said:
Gas cap would do it. i have had the same on mine, when I lived in NJ, you can't pump your own gas. The attendants wouldn't put the cap on right and in a couple of hours I would get the light. Crank it down...:thumb:
X2 bad gas cap threw a CEL on my girlfriends car, around $12 later for a new gas cap problem solved
 

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My TJ does that when I get her wet. I believe it has something to do with the oxygen sensors?

If its raining hard enough and the puddles are big it'll come on then, but goes off on its own or if I erase the code.

Probably nothing to worry about.
 

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Discussion Starter · #5 ·
Good to know the gas cap issue isn't anything new then. Will take the time to make sure it goes on correctly from now on (or order the hubby to do it right, since he's almost always the one to do it).

Doubt our issue would have anything to do with water. We live in the desert and I have yet to see anything resembling rain for as long as I've lived here (nine months). My husband claimed it rained once several months ago, but I just laughed as it wasn't anything resembling the downpours/thunderstorms I grew up with.

Is it a good idea to use Seafoam anyway? It is a used Jeep, former Border Patrol that got the crud beat into it. I assume it wouldn't hurt?
 

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Jacqui said:
About three days ago, I hopped into our 2006 LJ Rubi and noticed the engine light came in as soon as I started her up. My husband said it was not there a few hours prior. I listened carefully, revved the engine, drove around the block and everything seemed normal. My hubby's stepdad (mechanic) said to start with basic possibilities: 1) check to make sure the gas cover is on correctly. He said it can commonly cause the engine light to light up if it isn't in place on a Jeep. 2) It may have to do with emissions. He suggested using Seafoam in the gas tank as well as the fuel line.

We drove the LJ for two days with the engine light on (it's our only vehicle right now). And without using the Seafoam we bought, it went away. Haven't seen it all day. Any ideas as to what may have caused it? Has anyone else encountered this gas cover issue before? We're thinking that may have been the issue, as we did fill up the tank yesterday (thereby removing and replacing the cover), but I'd like to hear from the Wrangler community about common problems you've encountered. Thanks!
There are codes stored in the ecm.stop at any autoparts store and have them scan it.some will erase it for u and some want.emission related more than likely but its good to know what it is.
 

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seafoam works great. ive used it 4 or 5 times on my 05tj. but if you put it in your oil youve got to change it, so plan around that. otherwise put a little in your gas tank and suck some through your vacuum line from the brake booster. made mine run like a cadillac.
 

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Also with the 02 sensors,they sample air around them for a base line.any time u submerge them they kick the cel on.it happens to me once a month,one of the holes on the trails is deep water.by the time I get to the end,cel is on for high voltage.
 

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Wait a minute. Before you do anything, get the code to tell you what is wrong before wasting your time and money. (no offence to the stepdad but that was poor advice).

You can get the code yourself. Turn the key OFF-ON-OFF-ON-OFF-ON and the code will display in the odometer window. Look op the code on the forum (or just google it)
 

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I had an intermittent engine light from a bad throttle position sensor. Found out by getting the code from the odometer as described above. you live in the desert, how is the air filter?
 

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Discussion Starter · #11 ·
Hmm. Can't get a code to show. I assume that's because the CEL turned off already? If the light comes on again, now I know how to get the code. Thanks for that. :)

No idea on the air filter. We've only had the LJ for one month. Before we got our hands on it, it was a Border Patrol vehicle in Texas. Got real dirty but I know enforcement departments maintain their vehicles well (as far as changing oil, filters, etc... They could care less about paint lol!) so I assume it's still okay. How do I check that myself?
 

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(don't start the engine, just go off to ignition on three times within 5 seconds time without cranking the starter :thumb: )

The owner's manual should show how to do the air filter in detail. Should be the big black, plastic box on the passenger side under the hood, with the fat air hose going to the top of the engine. Unclip the cover and you can see if the filter is plugged up with heavy dirt. You have to lift the filter out and look at both sides and put it back in the same way with the filter's metal screen, if any, on the downstream air side (toward the engine.)
I don't have the factory air box, so this is just from my bad memory.
 

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My 97 2.5L has the check engine light that comes one every now and again. Being a mechanic by trade i just keep a handheld scanner in the glove box to erase it haha If you can get it checked by a mechanic get them to tell you what code comes up. It should be a P0XXX code. I cant remember exactly what my code is, but if it comes on every now and again but with no noticable issues with engine performance I wouldnt worry about it. Talking to other mechanics and Jeep guys its almost like a phantom code, and the only way to fix it is to start throwing parts at it, starting with the throttle postitioning sensor on the throttle body, but this only might fix it. hope this helps
 

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Discussion Starter · #14 ·
(don't start the engine, just go off to ignition on three times within 5 seconds time without cranking the starter )
Ah haaa. I wasn't doing it quickly enough during my earlier attempt. Got the code today: P 0456
A quick peek at Google yielded some information for me. The most common reason this error code pops up seems to be the gas cap issue. Since ours went away after adjusting the gas cap, I'm guessing that was indeed the problem. Spiffy. Would replacing the gas cap itself eliminate the appearance of this error in the future? Appreciate all the help, guys. Thanks. :thumb:
 

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Jacqui said:
Ah haaa. I wasn't doing it quickly enough during my earlier attempt. Got the code today: P 0456
A quick peek at Google yielded some information for me. The most common reason this error code pops up seems to be the gas cap issue. Since ours went away after adjusting the gas cap, I'm guessing that was indeed the problem. Spiffy. Would replacing the gas cap itself eliminate the appearance of this error in the future? Appreciate all the help, guys. Thanks. :thumb:
My LJ throws that code all the time...have tried locking caps and regular...i just get used to it. It was mentioned to me that humidity plays a huge part in that code.
 

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Discussion Starter · #16 ·
My LJ throws that code all the time...have tried locking caps and regular...i just get used to it. It was mentioned to me that humidity plays a huge part in that code.
Humidity. That made me giggle. We're in the desert. People here don't even know what humidity is. :p Ah well. We'll learn to live with the quirk, whatever it's true cause may be. :)
 

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Yes the EVAP (or caused by the gas cap) code should be "self-erasing" after a few start and warm-up engine cycles once the cause is taken care of.
 
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