Getting your vehicle ready for a smog check can be stressful, especially when you encounter the dreaded “OBD2 Not Ready” status. This means your car’s onboard diagnostic system hasn’t completed all the necessary self-tests, and it will fail the smog check, even if your car seems to be running fine. Let’s dive into what this means and what you can do about it.
When your car displays an “OBD2 Not Ready” message during a smog test, it indicates that one or more of your vehicle’s emission monitors are not in a “ready” or “complete” state. These monitors are crucial because they continuously check various emission control systems to ensure they are functioning correctly. Common culprits for a “Not Ready” status include the Catalyst Monitor and the Evaporative System (EVAP) Monitor. If these, or other monitors, haven’t completed their tests, your car will not pass the smog check.
One common reason for monitors to be “not ready” is a recent battery disconnection or car repair that involved disconnecting the battery. When the battery is disconnected, the car’s computer memory is reset, and the monitors reset to an “incomplete” state. They need to run specific drive cycles to perform their self-tests and switch back to “ready.”
So, what’s a drive cycle? A drive cycle is a specific set of driving conditions designed to allow your car’s onboard computer to run all the emission system tests. Different car manufacturers and models may have slightly different drive cycle procedures. For example, here’s a drive cycle suggested for a Toyota MR2 with a 2AZ-FE engine which can help reset monitors:
- Start the engine and let it idle for at least 10 minutes.
- Drive at a steady speed between 43-56 mph for 3 to 5 minutes, keeping the engine speed between 900 and 3,200 rpm.
- Stop and idle for 3 to 5 minutes.
- Repeat the drive and idle steps once more.
- Drive at 40-55 mph for 3 minutes.
- Drive at 35-45 mph for 7 minutes.
- Stop, turn off the engine, and release fuel tank pressure by briefly removing and reinstalling the gas cap.
- Restart and drive at approximately 45 mph for 5 minutes.
- Drive at around 25 mph for 15 minutes, including at least two 30-second stops.
- Stop and idle for 2 minutes.
- Drive at 25 mph or more for at least 50 seconds, ensuring engine speed is above 900 rpm.
- Stop and idle for at least 40 seconds.
- Repeat the previous two steps (“K” and “L”) ten times.
If, after performing a drive cycle, your monitors are still not ready, ensure all basic preconditions for your vehicle’s drive cycle are met. Then, turn the ignition off and repeat the entire procedure.
To check your OBD2 monitor status yourself, you might consider using an OBD2 scanner. These tools plug into your car’s OBD2 port and can read diagnostic information, including the readiness status of your monitors. A basic scanner, like the Autel MS309, can be an affordable option to check if your car is ready for a smog test, potentially saving you a trip to the testing station and back.
In conclusion, if you’re facing an “OBD2 Not Ready” for your smog check, don’t panic. Understanding drive cycles and using an OBD2 scanner can be valuable tools. However, if the “not ready” status persists even after trying these steps, it might indicate an underlying issue with your vehicle’s emission system that requires professional diagnosis.
