Emissions Irony

"subexpression" (subexpression) 08/21/2020 at 21:58 • Filed to: None

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Thanks to not driving much over the past several months, my emissions sensors were not in “ready” state when I needed my emissions test for new plates and the vehicle needed to be driven . Then some other work I needed (not related to emissions) reset all the sensor data , so go through it all again. Nobody seemed to know the drive cycle for some of these sensors - not the dealership service department , not the internet and Google, and if none of them have it then it’s probably locked in a secret vault somewhere near Detroit .

So today I’m gathering up all the paperwork to put it in my filing cabinet, and I can’t help but look at the mileage on the first and last forms. I’m not really driving much right now because COVID-19 means I’ve reduced my outings and a lot of what I would do is closed anyway, so I was doing a   loop around the nearby highways when I was out for something else or when I felt like it in the morning or evening . Plus I gave the mechanics permission to do some extra driving to try to get it done for me. I also gave it a few extra miles because I wanted to make sure all the sensors showed good even though I didn’t need the last one to pass the test - if I’m going to this much trouble, I want to fix everything that needs fixing and have it over and done with .

Even if I factor out a rough estimate of the trips I would have made anyway, the drives to/from the dealership, a reasonable number of miles for road testing after work was done, etc., the total driving done by the mechanics and me for the first test and the second has to be close to 1000 miles. 1000 miles worth of exhaust from a 5000+ lb   SUV for the sole purpose of passing an emissions test that is based entirely on plugging in to the OBDII port . I’m not sure that’s a win for anybody.

dogisbadob > subexpression 08/21/2020 at 22:51

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can you do the drive cycle on jack stands?

What kind of car is it?

For cars 2001 and newer, you can have one monitor not ready and still pass. For cars 1996-2000, you can have 2 monitors not ready

subexpression > dogisbadob 08/21/2020 at 23:21

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You might be able to do it on 4 jack stands... if you knew what it needed.

It’s a Grand Cherokee with the 3.0L diesel. I can pass emissions with one sensor not ready. The two that took the longest were related to the SCR and DPF systems, which are a pain in the ass just in general . I’m pretty sure getting those sensors to go ready requires that the engine be hot and running at speed, so highway runs after the engine is already warmed up are probably the only thing that counts toward readiness .

smobgirl > subexpression 08/22/2020 at 00:39

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I somehow passed with mine not ready - and they weren’t ready specifically because I unplugged the battery to get the check engine light to turn off. Hoping I can get a roadside reading before the next emissions test is due  and pass that way.

Eury - AFRICA TWIN!!!!!!! > subexpression 08/22/2020 at 06:59

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What a pain. I rescued a rotting TJ from a field a few years ago and went through the same thing. It ended up taking almost 800mi to  get everything going. In a TJ, with no doors, in winter l, in NH. So stupid. 

Long_Voyager94 > dogisbadob 08/22/2020 at 07:25

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Even on jackstands it’s still running and producing emissions......

Taylor Martin > subexpression 08/22/2020 at 19:38

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This just reminded  me that I need to go get my car tested. Just expired this month. Thank you. You’re my hero.

atfsgeoff > subexpression 08/22/2020 at 20:11

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Jesus, I’ve never heard of an emissions ready drive cycle that long. Most I’ve ever heard of is about a hundred miles.