Long story short, I've been failing multiple smog checks for the past 3 months because my monitors aren't ready. A little background - the truck was desmogged for about 1.5 years and recently put everything back on. Failed the first smog check back in November right after all the original equipment was reinstalled because of monitors so I gave it another month or so and 500+ miles. Same thing happened again after an additional 1000 miles and 2 months. No error codes, etc.

It seems to be different monitors not being ready at each smog check.

The only suspicion I have is that one of the sensors was damaged while I had the DPF equipment in storage (the thing weighs over 100 lbs and I had to drag it out of my crawlspace).

Any help would be greatly appreciated.

 

Did you reprogram the computer back to OEM? Most deletes have a tuner program to stop cel's.

 

If everything is functional, there's a drive cycle procedure to get the emission readiness monitors set. It took me quite a while and a lot of miles to get mine to set so I could pass emissions. Mine happened when I removed my batteries since it resets all the monitors.
Here's a snip from the manual on how to do it. It's on page 394 in the owners manual.

The OBD-II system is designed to check the emission control system
during normal driving. A complete check may take several days. If the
vehicle is not ready for I/M testing, the following driving cycle consisting
of mixed city and highway driving may be performed:
15 minutes of steady driving on an expressway/highway followed by
20 minutes of stop-and-go driving with at least four 30-second idle
periods.

If there's a bad sensor, you'll need to do this after you get it fixed to get it ready for I/M. It is a pain to get them to set.
You can also use Torque Pro to monitor them so you know when they are ready. Which is what I did.

 

Yes, everything is back to stock. My mechanic has also checked for codes multiple times. We even tried a few forced regen cycles at various points over the last few months.

 

Unfortunately I've tried this several times with hundreds of miles in between each attempt. I'll give the OBD2 reader a try.

If a sensor is bad, wouldn't there be a CEL of some sort?

 

 

Take it to a different smog shop.
Also the truck needs to be completely warmed up. That means transmission and everything. You need to drive the truck for at least 30 minuets to make sure the truck is hot. If a sensor isn't reading a CEL will occur. Sounds like your is just fine and the smog equipment has a problem.

 

Are they failing you based on the data the truck is reporting or are they sticking a probe in the tailpipe? Does any state still stick a probe in the tailpipe.

 

No probes in the tailpipe in CA as far as i know - all based off the computer. They arent even running the test because the monitors are not reporting as being ready.

 

Have you returned the stock tune in the truck? Tuners shut the sensors off when they remove all this stuff. They may be still there but the tune overrode them.

 

Would love to know what the end result here. I am in the same exact situation as you in CA and can’t get the catalyst and pm filter monitors to set.

 

You have to drive the truck on the highway and in town for about 50 miles. There is a exact procedure but I just go out and drive my car till all the sensors turn back on.

 

I’ve driven 300 miles and the catalyst and pm filter monitor won’t go through

 

Have you checked to make sure the sensors are plugged in. I would unplug them and do it again.

 

I thought diesels 07 and newer could pass smog with 2 incomplete readiness monitors (no more than 2).



From the www.bar.ca.gov website