2001 TJ wont pass smog inspection

Clarythedrill

Clarythedrill

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Ft. Worth, Texas
I have a 2001 TJ with the 4.0 engine. I got a code about a month ago of P0456, small evap leak or something like that. I did just a little research and decided to change out the gas cap to see if that will fix it. I put on the new gas cap and then disconnected the battery for while and reconnected. I then drove it for about 50 miles and went to get it inspected. It failed for evap not ready, so no really a failure, but the system was not reporting since it did not have enough drive time.

I put my own OBD scanner on it and drove for another 75 miles, but it is still saying not ready. How many miles does it usually take to report, pass or fail? Is there something else I need to check? Thanks for any help.
 
The ECM runs a set of "Monitors" which take a while to complete, with specific driving conditions. Your OBD scanner should be able to show you which "Monitor Tests" have not yet completed (in case there are other incomplete ones besides the Evap). Some monitors need to complete before others can run. Check which monitors are not yet complete. I don't know about your '01, but my '05 has 7 of the 11 possible OBD monitors.

There is a generic OBD Drive Cycle which is supposed to get all of the monitors completed, but it is complex and sometimes impossible to do. Instead, Chrysler has simpler individual drive cycles you can run to get specific monitors to complete. The attached PDF file will tell you how to run the Evap drive cycle, along with all the others.
 

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if i remember correctly that system performs it test between a full tank and 3/4 tank of gas. fill it up then drive it and it should complete the check !
 
OldBuzzard said:
The ECM runs a set of "Monitors" which take a while to complete, with specific driving conditions. Your OBD scanner should be able to show you which "Monitor Tests" have not yet completed (in case there are other incomplete ones besides the Evap). Some monitors need to complete before others can run. Check which monitors are not yet complete. I don't know about your '01, but my '05 has 7 of the 11 possible OBD monitors.

There is a generic OBD Drive Cycle which is supposed to get all of the monitors completed, but it is complex and sometimes impossible to do. Instead, Chrysler has simpler individual drive cycles you can run to get specific monitors to complete. The attached PDF file will tell you how to run the Evap drive cycle, along with all the others.
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Yes, my OBD ready lists about 11 things that are monitored, and all check out fine except the evap. It doesnt say it passes or fails, just that it isnt ready. I think I will just do alot more driving and keep checking. Thanks.
 
You can't inspect in a different county than you register in TX. Well, you probably can but it will bite you when you go to get your sticker.

You may have your own opinions on this sort of thing, but I know in Collin County there are some inspection places that have an off the menu option for about $100 to "fix the issue." I have a friend in an XJ with a computer that won't communicate on the OBDII port, so it won't pass. That one required a $75 "tax stamp" to correct.

The whole thing is just silly. If you want to know about my emissions, then put a sniffer on my exhaust and measure them. I realize O2 sensors and all that are there to control emissions, but if my car runs clean the computer transmitting data shouldn't be a limiting factor. But it's not about emissions, it's about a revenue stream.
 
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The system only checks on cold start and the tank has to be somewhere between 3/4 and 1/4, I forget the exact numbers but your situation would have never done the test.
this was from another thread here.
 
@tr21triton is correct, the system will check on cold start and if the test passes the light will immediately go out, no drive is required. If the cap doesn't solve the issue the next easy step is checking the vacuum lines under the hood. Especially the elbows at the intake manifold and purge solenoid if an 01 has them.
 
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pagrey said:
@tr21triton is correct, the system will check on cold start and if the test passes the light will immediately go out, no drive is required. If the cap doesn't solve the issue the next easy step is checking the vacuum lines under the hood. Especially the elbows at the intake manifold and purge solenoid if an 01 has them.
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Once I replaced the gas cap and cleared the code, the check engine light has not come back on. My issue is the evap shows "not ready" when you scan the vehicle. It does not either pass nor fail, just shows no ready, which will fail you when being inspected. I will continue to drive and see if it either shows good or the check engine light comes back on.
 
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If evap isn't ready and there is no check engine light that means you cleared the codes and you haven't met the conditions required to do a single test described by @tr21triton. It's totally normal. After you have 1/4-3/4 tank and do a cold start you'll either be good to go or get a check engine light and be not good to go. If the Jeep doesn't do the test under the conditions described you have a PCM issue and no amount of driving will fix it.
 
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Clarythedrill said:
Once I replaced the gas cap and cleared the code, the check engine light has not come back on. My issue is the evap shows "not ready" when you scan the vehicle. It does not either pass nor fail, just shows no ready, which will fail you when being inspected. I will continue to drive and see if it either shows good or the check engine light comes back on.
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yea, I think your PCM has failed ! contact @Wranglerfix for a replacement .
 
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lulzpwndyah said:
I registered in a no smog county in Ca. Now i'm just afraid of being pulled over and them saying something about the address being 200 miles from my residence
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You'd think California would have bigger issues to concern themselves with... but you're right, they would absolutely love to "tax" you some more!
 
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Yep, I hate it. It's literally just taxing for the heck of it at this point. Would be easy to use a sniffer and be like yep this guy is well within emissions. I have a new engine, new cats, new pcm, new 02s but one stupid code that I can't figure out and it's an automatic fail
 
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To use a sniffer properly requires somebody that actually knows how things work. Back in the 90's I had a California smog license and it required a week of classroom instruction and a fairly comprehensive test to get.
If all you have to do is hook up a scanner and read a list that says done or not done, you can hire the pasty-faced kid that just got canned from AutoZone for smoking weed in the back room. Economics.
 
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Clarythedrill said:
Once I replaced the gas cap and cleared the code, the check engine light has not come back on. My issue is the evap shows "not ready" when you scan the vehicle. It does not either pass nor fail, just shows no ready, which will fail you when being inspected. I will continue to drive and see if it either shows good or the check engine light comes back on.
Click to expand...
so did it ever get fixed ?
 
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