OBDII "Not Ready" for SMOG TEST

[bsmall2800]

I have a 2020 GMC 3500 Duramax and went to get it smog check. The guy said that my OBDII is "NOT READY" . He asked if the batteries or any work done on the truck lately. No to both. He said drive it around for about 100 miles and hopefully things will reset and able to complete the Smog Test. I drove is for about 50 miles and he checked and said its still Not Ready to complete the Smog Test.
I was just wondering if anyone else has experienced the same issues and what you did to make the engine ready for the Smog Check.
Thanks in advance!

 

[darkness]

Check your cigarette lighter fuse. I don’t know if they still get power for the obd2 plug from there. If they even have those anymore.

 

[455buick]

I'm assuming he's meaning that the emissions systems readiness monitors aren't "ready". Some of those monitors take a very long time to meet their criteria to be "ready". I think the line for that smog test would be miles long if they require the vehicle to have every readiness monitor "ready", but if the line were that long some of the readiness monitors would not be "ready" by the time of the test. Depending on application, some people don't ever hit some systems to "ready". Just my speculation though.

 

[2004LB7]

I'm guessing at least one monitor not ready too. If I remember correctly, I think one of them is actually call OBD monitor. Each monitor has it's own requirements for passing. Some require one or more "cold" starts while others need to see specific driving conditions.

The typical GM drive cycle that will clear most readiness monitors if nothing is wrong:

Start the vehicle from a cold start. The time to do this is if you have not driven the vehicle for a few hours and the engine coolant temperature is less than 50 degrees F.
Let the engine run on idle. Turn the A/C and rear defroster on. You are trying to apply electrical load to the system.
Accelerate to 55 mph.
Hold a steady speed of 55 mph for 3 minutes
Let go of the accelerator and coast until the vehicle hits 20mph. Don’t apply brakes to slow down.
Accelerate again until 60 mph.
Hold steady for 5 minutes at 60mph for 5 minutes.
Decellerate (coast to slow down).
You may need to repeat steps 3-8 a few times

 

[bsmall2800]

I will try that procedure to see if it will clear the Not Ready when they do the Smog Check again. Thanks so much for your help.

 

[2004LB7]

I think on the newer rigs, Nox sensors and oxygen sensors are the biggest reason for readiness monitor issues. And they don't always set codes until they get bad enough

 

[Ron Nielson]

https://www.gm-trucks.com/forums/topic/247108-ckp-replacement/
Scroll to near the bottom and look for info on getting the drive cycles completed

 

[bsmall2800]

After 3400 miles of driving and completing the drive cycle still "Not Ready" shows up when the Smog Station plugs in the OBD monitor. This is so frustrating for a 4 year old vehicle. The Chev dealership says another Duramax came in with the same issue and the technician plugged all his equipment in and took it out for a drive while being able to monitor everything. He said he was able to get it in the Ready state. So now all I have to do is get my truck up there and have the same procedure completed. Hopefully it'll work for my truck.
The cost is about 150.00 of course this all depends on just how long it takes the technician to complete the status change.
I'll keep posting updates!