Encountering a “not ready” status during a smog check can be frustrating. If your smog inspection report indicates that your car is “not ready,” specifically mentioning the Catalyst and Evap System monitors, it means your vehicle’s On-Board Diagnostic System (OBDII) hasn’t completed its self-tests for these crucial emissions control components. This incomplete status will prevent you from passing the smog test, even if there isn’t a major underlying issue.
These “readiness monitors” are essentially checks the car’s computer performs to ensure emission control systems are functioning correctly. The Catalyst monitor evaluates the efficiency of your catalytic converter, while the Evaporative System (Evap) monitor checks for fuel vapor leaks in your fuel system. If these monitors haven’t run and completed their tests, they will show as “not ready.”
One common method to set these monitors to “ready” is to perform a “drive cycle.” A drive cycle is a specific series of driving conditions that can trigger the OBDII system to run its diagnostic tests. For example, a Toyota MR2 with a 2AZ-FE engine might respond to the following drive cycle to reset its monitors:
- Start the engine and idle for 10+ minutes.
- Drive at 43-56 mph (900-3,200 rpm) for 3-5 minutes.
- Idle for 3-5 minutes.
- Repeat the previous two steps once.
- Drive at 40-55 mph for 3 minutes.
- Drive at 35-45 mph for 7 minutes.
- Stop, turn off engine, release fuel tank pressure by briefly removing the fuel cap.
- Restart and drive at 45 mph for 5 minutes.
- Drive at 25 mph for 15 minutes (with two 30-second stops).
- Idle for 2 minutes.
- Drive at 25+ mph (above 900 rpm) for 50+ seconds.
- Idle for 40+ seconds.
- Repeat the last two steps ten times.
If, after attempting a drive cycle like this, your monitors are still “not ready,” it’s crucial to ensure all preconditions for the monitors to run are met. If issues persist, further diagnosis with an OBDII scanner may be necessary to identify potential underlying problems preventing the monitors from completing. Tools like the Autel MS309 can be helpful for reading readiness monitor status and checking for diagnostic trouble codes that could shed light on why your car is not ready for a smog test.
