What Diesel Drivers Need to Know About Smog Tests After Completing Recall 67A

If you’re required to complete smog or emissions testing in your area, you might be wondering how Emissions Recall 67A could impact your next test. When an update to the engine control module (ECM) is performed, OBD monitors are reset and will need a period of time to reinitialize. Many drivers choose to complete their smog tests before they proceed with Recall 67A. However, either option is acceptable. If you choose to complete the Recall first, your truck may need to be driven for a period of time before it is in a “ready state” to successfully pass the smog test. This is a normal part of how modern diesel engines work, and with some driving, your truck should be ready. Let’s break it down so you can stay on the road with confidence.

Understanding Smog Tests: What They Are and Why They Matter

A smog test, or emissions inspection, is a mandated check that ensures vehicles aren’t releasing excessive pollutants into the air. For diesel vehicles, they help verify that systems like your Diesel Exhaust Fluid (DEF) dosing and NOx sensors are functioning properly.

Smog test requirements can vary. To find out what’s required where you live, check with your state’s Department of Motor Vehicles (DMV) or environmental agency. Staying on top of your testing schedule ensures you’re always road ready.

How Smog Testing Works Today- and What It Means for Diesel Owners

Today’s smog tests focus less on what’s coming out of your exhaust and more on what your vehicle’s on-board diagnostic (OBD) system reports. This system continuously monitors critical emissions equipment — like your DEF injector, particulate filter and NOx sensors — ensuring everything functions properly.

For diesel owners, a successful smog test depends on two things: your emissions output and your OBD system’s ability to complete self-checks, known as readiness monitors. If that data isn’t available, the system might show as not ready, even when everything is operating correctly.

Smog Tests, Recall 67A and Your Cummins 6.7L Diesel Engine

Because Recall 67A updates the engine control module, specifically adjusting how your diesel exhaust fluid (DEF) system doses, the OBD system monitors are reset. If you attempt a smog test too soon after the update, it may return a “not ready” result. This is normal and does not indicate a defect or failure in your vehicle.

With some drive time, your vehicle will generate the necessary data to pass your smog test. In some cases, it takes a full drive cycle — a mix of city and highway driving. For this reason, completing Recall 67A about a month before any planned smog test is often sufficient to ensure the system is in a ready state.

Final Takeaway: It’s Rare; It’s Normal; and We’re Here to Help

Most trucks pass smog tests after Recall 67A without any additional action needed. However, because the update resets the OBD monitors, they will need time to reset and relearn before the vehicle is ready for testing. If you need help getting your truck into a ready state for a smog test, please contact your local Ram dealership.