To pass a Clean Truck Check emissions test, your truck’s OBD (On-Board Diagnostics) system needs to meet certain conditions.
Here’s what that means in simple terms:
Your truck must have no active or permanent trouble codes (these are issues the OBD system detects).
It must also meet one of these:
Completed at least 5 warm-up cycles (a warm-up cycle is when the engine starts cold and warms up to normal temperature).
Driven at least 200 miles.
Run for at least 400 minutes (about 6.5 hours of engine time).
Have no more than 2 incomplete OBD monitors (these are systems the truck checks, like emissions or fuel systems).
If your truck has a permanent trouble code, it can still pass, but the requirements are stricter.
The code will be ignored if your truck meets one of these:
Completed at least 15 warm-up cycles.
Driven at least 400 miles.
Run for at least 800 minutes (about 13 hours of engine time).
Have no more than 1 incomplete OBD monitor.
If your truck doesn’t meet these requirements, it will get a “Not Ready” result and won’t pass the emissions test.
If this happens, keep driving the truck as you normally would for a few days, then have it retested.