Dealing with a failed smog check can be frustrating, especially when the report indicates “OBD2 Not Ready.” This often means your vehicle’s onboard diagnostic system hasn’t completed its self-tests, specifically for crucial emissions components like the Catalyst and Evaporative (Evap) System. But what does this actually mean, and more importantly, how can you fix it to pass your smog test?
To ensure your vehicle is accurately assessed for emissions, the OBD2 system runs various monitors. These monitors need to complete their cycles to confirm that all emission control systems are functioning correctly. If these monitors, particularly the Catalyst and Evap monitors, are not in a “ready” state, your vehicle will fail the smog check, even if there are no apparent issues.
One common reason for “not ready” monitors is a recently cleared trouble code or a disconnected battery. When the OBD2 system’s memory is erased, these monitors reset and need to run through a specific “drive cycle” to become ready again. A drive cycle is a predetermined set of driving conditions that allows the vehicle to perform these self-tests.
If you’re driving a Toyota MR2 with a 2AZ-FE engine and facing a “not ready” status for your Catalyst and Evap monitors, a specific drive cycle might help. Here’s a drive cycle procedure that could be effective:
- A. Start your Toyota MR2 and let it idle for at least 10 minutes.
- B. Drive at a steady speed between 43-56 mph for 3 to 5 minutes, ensuring the engine speed stays between 900 and 3,200 rpm.
- C. Stop the vehicle and idle for 3 to 5 minutes.
- D. Repeat steps B and C once more.
- E. Drive at 40 mph to 55 mph for 3 minutes.
- F. Drive at 35 mph to 45 mph for 7 minutes.
- G. Stop, turn off the engine, and relieve fuel tank pressure by briefly removing and reinstalling the fuel cap.
- H. Restart the engine and drive at approximately 45 mph for 5 minutes as soon as it’s safe to do so.
- I. Drive at about 25 mph for 15 minutes, including at least two 30-second stops.
- J. Stop and idle for 2 minutes.
- K. Drive at 25 mph or more for at least 50 seconds, keeping engine speed above 900 rpm.
- L. Stop and idle for 40 seconds or more.
- M. Repeat steps K and L ten times.
A close up image of the Autel MS309 OBD2 Scanner screen displaying diagnostic trouble codes, highlighting its functionality for reading and interpreting vehicle fault codes.
If, after completing this drive cycle, your monitors still show as “not ready,” double-check that all preconditions for the monitors to run are met. Then, turn off the ignition and repeat the entire drive cycle from step A to M.
For vehicle owners and DIY mechanics, having an OBD2 scanner can be incredibly helpful. These tools allow you to check your vehicle’s readiness monitor status yourself, read diagnostic trouble codes, and even clear codes after repairs. This can save you time and money by allowing you to confirm monitor readiness before heading to the smog check station.
By understanding the “OBD2 Not Ready” status and utilizing tools like OBD2 scanners and specific drive cycles, you can effectively address these issues and ensure your vehicle is ready to pass its next smog inspection.
