2001 TJ wont pass smog inspection

tr21triton said:
so did it ever get fixed ?
Click to expand...
No, I havent driven it much in the last couple of days. I will be driving it today about 100 miles, so that along with the miles already on it should give it enough time to finish any checks. I hope so anyway, since my 14 day grace period for not paying again is almost up.
 
This cycle will run the evap monitor:
Like others mentioned 3/4 to full tank
From 6-8 hours of the vehicle being off (cold soak), idle for 5 minutes
Drive in city traffic naturally with stops and acceleration for 5 minutes.
Stop. Idle vehicle for 4 minutes.
 
This cycle should run the evap monitor. Like others mentioned 3/4 to full tank
Trace 2: Leak Detection Pump
From 6-8 hours of the vehicle being off (cold soak), idle for 5 minutes
Drive in city traffic naturally with stops and acceleration for 5 minutes.
Stop. Idle vehicle for 4 minutes.
 
Honeybadger said:
This cycle will run the evap monitor:
Like others mentioned 3/4 to full tank
From 6-8 hours of the vehicle being off (cold soak), idle for 5 minutes
Drive in city traffic naturally with stops and acceleration for 5 minutes.
Stop. Idle vehicle for 4 minutes.
Click to expand...
Thank you for this info. I will do that tomorrow after driving today, just to make sure.
 
Clarythedrill said:
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.
Click to expand...
Take a resistor pull +- batt cables put resistor( + Res -) between resistor for a minute, it will discharge Capacitors resetting to factory default and clear code
 
Clarythedrill said:
No, I havent driven it much in the last couple of days. I will be driving it today about 100 miles, so that along with the miles already on it should give it enough time to finish any checks. I hope so anyway, since my 14 day grace period for not paying again is almost up.
Click to expand...
Oklahoma has no smog test just get mail box plus box you can use box # as Apartment # not at USPS Office that won't work. I did that in Fl till NC stopped smog.
 
CharlesHS said:
Generally takes up to 5 drive cycles and as much as 200 miles for ALL to set.
Click to expand...
evap system test will not show ready until the condition explained in posts # 3, 9, 12 and 14 are meet ! the computer only runs the evap sys. test when the gas tank is between 3/4 and a 1/2 tank if I remember and from a cold start up. and I recommend if you have to replace parts replace both the evap cannister and purge valve because most of the time the charcoal leaks in the cannister and screws up the purge valve, so if you just replace the valve it will just screw up the new valve in short time.....also blow out the hoses to remove charcoal remaining in them....
 
Clarythedrill said:
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.
Click to expand...
It's not just the # of miles driven for it to be considered ready, it's the number of full cold-warm cycles and perhaps a couple other requirements like being between 1/4 an 3/4 tank of gas and driving various speeds. My Genesis has an 18 step cycle that has to be done before it will consider everything ready.
 
  • Like
Reactions: tr21triton
b. Evap sensor - does not need any driving at all. The vehicle does not need to be on jack stands. Extremely sensitive to air temperature, so if you are in Texas in the summer, you have a problem. Mine is equipped with Leak detection Pump, so it is applicable for it.
From the factory manual:
Page 4 in general information section - This monitor requires a cold start, usually an overnight soak or parked for at least 8 hours without the engine running. The engine coolant temperature must be within 10 degrees of ambient/battery temperature, and the sensed Ambient (outside) Temperature must be be- tween approximately 40° F and 90° F.
Page 7 in general information section- Conditions on Evap monitor running - Cold start: with ambient temperature (obtained from modeling the inlet air temperature sensor on passenger vehicles and the battery temperature sensor on Jeep & truck vehicles) between 4°C (40°F) and 32°C (90°F) for 0.040 leak. Be- tween 4°C (40°F) and 29°C (85°F) for 0.020 leak. Engine coolant temperature within: -12° to -8°C (10° to 18°F) of battery/ambient. Battery voltage between 10 and 15 volts. If battery voltage drops below 10 volts for more than 5 seconds during engine cranking, the EVAP leak detection test will not run. Low fuel warning light off (fuel level must be between 15% and 85%). MAP sensor reading 22 in Hg or above (This is the manifold absolute pressure, not vacuum). No engine stall during test.

The procedure:
1. Make sure the gas tank is slightly under 75% full and slighly above 50% full. It possible that it will work fine with other gas tank levels, but i did not experiment with them.
2. Let the vehicle cool down for at least 10 hours, so that the engine temperatures will get into the 10 degree delta from the ambient air temperature.
3. Make sure that the ambient air temperature is around 75 degrees (which is a problem here in Texas in summer). It is possible that it will run with higher temperatures, but it did not work well for me. I had to put it outside of the garage, and wait 3-4 days till the air temperature was low enough at around 1AM (reached 75 degrees). I tried it every night, and it failed, till the coldest (I mean like Texas coldest) night with 75 degree at 1AM, where it worked. It is possible that the upper thermal boundary depends on tear and wear on the system, so it might work for you at 85C as well, if it is in much better shape.
4. Start the engine in when transmission in Park, and just idle for 5 minutes. Keep AC, lights and everything else off. Don't use steering wheel as well.
5. Shut the engine, remove the key.
6. Leave it it alone for 20 minutes
7. Come back and run the scan with scan tool, and verify that the monitor is ready.
 
As of right now air temperature is beyond 90F, so it it will be very hard to clear the evap. I cleared by waiting for colder night, and following the precise procedure above.
 
Top Bottom
Back