Emissions Not Ready, another thread
10-19-2020, 10:37 AM
#1
JK Enthusiast
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Emissions Not Ready, another thread
Back story on my Jeep - 2008 JKU, approx 170k on the odometer. Has been lifted, regeared, and modified with a tuner. In 2018 my PCM went bad - I was having misfires that resolved once the PC was replaced. Since then I have repeatedly been unable to pass inspection, it has been Not Ready the entire time.
At the direction of my local shop I replaced the cats and all 4 O2 sensors, as their readings were not normal according to their scan when they drove it. After that, the EGR valve caused a CEL, which I replaced and it resolved, then another CEL developed pertaining to 2 of the new O2 sensors. Those were replaced by my shop and that CEL cleared as well.
I currently have no open CELs and no abnormal codes when I scan it, but it still reads as not ready particularly the Catalyst and Oxygen Sensors. Nothing I have done has helped. I have reverted it back to stock with my tuner and driven hundreds of miles since then with no change. I had the PCM reflashed by the dealer as well with no difference.
Could this be a bad PCM??? I'm probably $2k into trying to get this fixed and I'd really like to get it to pass inspection so I can update my registration, which expired way back in 2018...
At the direction of my local shop I replaced the cats and all 4 O2 sensors, as their readings were not normal according to their scan when they drove it. After that, the EGR valve caused a CEL, which I replaced and it resolved, then another CEL developed pertaining to 2 of the new O2 sensors. Those were replaced by my shop and that CEL cleared as well.
I currently have no open CELs and no abnormal codes when I scan it, but it still reads as not ready particularly the Catalyst and Oxygen Sensors. Nothing I have done has helped. I have reverted it back to stock with my tuner and driven hundreds of miles since then with no change. I had the PCM reflashed by the dealer as well with no difference.
Could this be a bad PCM??? I'm probably $2k into trying to get this fixed and I'd really like to get it to pass inspection so I can update my registration, which expired way back in 2018...
10-19-2020, 05:52 PM
#3
JK Junkie
Two possibilities come to mind: The tuner did something that was not reversed when going back to stock (doubtful with a dealer re-flash), or your driving doesn't normally include the type of driving necessary to complete the test. My experience is that the O2 and Cat will be complete testing after ~15 min of mostly ~2000 RPM and ~45 MPH at cruise throttle (level ground, warm engine, with as steady RPM as possible). If you can graph the O2 sensors, they should look like this example at idle (steady speed driving is similar, but with a faster cycle for the upstream sensors):
Last edited by Mr.T; 10-19-2020 at 06:01 PM.
10-20-2020, 12:24 PM
#4
JK Freak
In many states (GA I know) you can still get a registration by simply proving you have invested a xx dollars in the attempt to resolve the problem. I know that will add up but at least you can get the registration and that gives you a year to resolve it. Just a thought to check on.