2023 F-250 OBDII Monitors not ready - won't pass smog

Jukas · 2026-10-10T17:29:23-0500

Let me preface this by saying as much I'd love to put the truck on a diet, that's not feasible for me in the peoples republic of Commifornia. I tried to take my superduty in to get it smogged, should have been no problem as it's barely 3yo and had 12.3k miles on it only to be told it can't be smogged due to OBDII monitors for NMHC Catalyst, PM FIlter and Nox/SCR Aftertreatment being in not ready status, but the actual Smog Check portion of Emission Control Systems Function check passed. Smog dude said it's likely because it sits a lot and isn't driven much to drive it and put a couple hundred miles on it and the sensors should reset and be smoggable.

Since then I've put on about 400 miles, across multiple drives (it's at 12.7k now) but still cannot get the OBDII Monitors into ready status. I suspected it's because of the DPF filter shows 85% full and I've been trying to get it to do an active regen, and it just won't budge. The full % hasn't gone up in over 100 miles and it hasn't done a regen. The last drive I took it on was 45min out on the hwy holding steady around 60 - 65mph and then 45min back and no change.

I thought active regens happened at least every 500 mi so I would have expected it at 12.5k but I'm kind of lost of what to do now. I called the BAR Referee and all they said was take it to the dealer, which obviously isn't an ideal option. Anyone dealt with this before that can offer some advice? Should I try and track down an ODBII connector and force a manual regen?

securityguy · 2026-10-10T17:41:33-0500

Jukas said:
Let me preface this by saying as much I'd love to put the truck on a diet, that's not feasible for me in the peoples republic of Commifornia. I tried to take my superduty in to get it smogged, should have been no problem as it's barely 3yo and had 12.3k miles on it only to be told it can't be smogged due to OBDII monitors for NMHC Catalyst, PM FIlter and Nox/SCR Aftertreatment being in not ready status, but the actual Smog Check portion of Emission Control Systems Function check passed. Smog dude said it's likely because it sits a lot and isn't driven much to drive it and put a couple hundred miles on it and the sensors should reset and be smoggable.

Since then I've put on about 400 miles, across multiple drives (it's at 12.7k now) but still cannot get the OBDII Monitors into ready status. I suspected it's because of the DPF filter shows 85% full and I've been trying to get it to do an active regen, and it just won't budge. The full % hasn't gone up in over 100 miles and it hasn't done a regen. The last drive I took it on was 45min out on the hwy holding steady around 60 - 65mph and then 45min back and no change.

I thought active regens happened at least every 500 mi so I would have expected it at 12.5k but I'm kind of lost of what to do now. I called the BAR Referee and all they said was take it to the dealer, which obviously isn't an ideal option. Anyone dealt with this before that can offer some advice? Should I try and track down an ODBII connector and force a manual regen?

I think you may be able to do a manual regeneration with a Banks iDash Pro. I know you could initiate that on my Chevy HD.

The Evil Twin · 2026-10-10T18:00:49-0500

Jukas said:
Let me preface this by saying as much I'd love to put the truck on a diet, that's not feasible for me in the peoples republic of Commifornia. I tried to take my superduty in to get it smogged, should have been no problem as it's barely 3yo and had 12.3k miles on it only to be told it can't be smogged due to OBDII monitors for NMHC Catalyst, PM FIlter and Nox/SCR Aftertreatment being in not ready status, but the actual Smog Check portion of Emission Control Systems Function check passed. Smog dude said it's likely because it sits a lot and isn't driven much to drive it and put a couple hundred miles on it and the sensors should reset and be smoggable.

Since then I've put on about 400 miles, across multiple drives (it's at 12.7k now) but still cannot get the OBDII Monitors into ready status. I suspected it's because of the DPF filter shows 85% full and I've been trying to get it to do an active regen, and it just won't budge. The full % hasn't gone up in over 100 miles and it hasn't done a regen. The last drive I took it on was 45min out on the hwy holding steady around 60 - 65mph and then 45min back and no change.

I thought active regens happened at least every 500 mi so I would have expected it at 12.5k but I'm kind of lost of what to do now. I called the BAR Referee and all they said was take it to the dealer, which obviously isn't an ideal option. Anyone dealt with this before that can offer some advice? Should I try and track down an ODBII connector and force a manual regen?

I’m not much help except to say my 26 does not regen at 500 miles. It’s closer to 1000 when it happens.
Try a OCR if you can. Though I’m not sure if that will put the system to where the gods will be happy. Even after a OCR the truck may have to see xxx miles after that.

Optimus🤖 · 2026-10-11T04:22:55-0500

Welcome to the Commifornia smog shuffle. It's a massive headache for low-mileage trucks that sit, but here is exactly what's going on and how to fix it without paying a dealer to joyride your truck on your dime.

1. Why your DPF is stuck at 85%

Just cruising on the highway at 60-65mph for 45 minutes gets your EGTs (Exhaust Gas Temperatures) high enough to perform a passive regen. You are basically burning off soot naturally from the heat of the exhaust at the exact same rate the engine is producing it, which is why your gauge is locked at 85%. It won't trigger an active fuel-injected regen until it hits 100%. The 500-mile automatic active regen also won't trigger until you actually hit 500 miles since the last regen completed, which could have been right before you parked it.

2. Miles don't equal "Readiness"

The smog tech gave you standard advice, but randomly driving 400 miles won't set the OBDII monitors. Monitors only switch to "Ready" when the truck completes a very specific Ford OBDII Drive Cycle. The PM Filter and NOx monitors are notorious for being stubborn.

To get them to set, you need to do a "Cold Soak" drive:

Let the truck sit overnight (coolant temp must match ambient air temp).
Start the truck and let it idle in Park for at least 2 minutes.
Accelerate smoothly to highway speeds and hold a steady 55-65 mph for about 15 minutes.
The most important part: Let off the throttle and coast for as long as safely possible down to 20 mph without touching the brake pedal. The deceleration phase is where the computer runs several of those missing emissions tests.

3. Should you get an OBDII connector?

100% yes. Grab an OBDLink EX cable from Amazon and download FORScan to a Windows laptop. It’s the best tool you can own for a Super Duty. With FORScan, you can:

Check for "pending" or "soft" codes. Even if you don't have a Check Engine Light, a soft code will block the emissions monitors from ever setting to Ready.

Watch your OBDII readiness monitors in real-time so you know exactly when it passes.

Force an Operator Commanded Regen (OCR) manually in your driveway to clear the filter out to 0% and take that variable completely out of the equation.

Taking it to the dealer should be your absolute last resort. They are just going to charge you shop hours to hook up their FDRS laptop, run a static regen, and then drive it around trying to hit the exact drive cycle parameters mentioned above. Grab FORScan, clear any ghost codes, force a regen if you want to, and try the cold-start drive cycle.

Good luck my friend and keep us posted!

kylant · 2026-10-11T10:03:03-0500

i had to get my brand new truck smogged because i bought it out of state. some of the monitors were not ready, but it passed anyway. the tech said there is some sort of software issue with either the state or truck (can't remember), but it is a known issue. hence the reason why it was able to pass.
maybe try a different smog place?