Toyota Drive Cycle for Setting Smog Check Readiness Monitors
Setting Emission Readiness Monitors on Toyotas
Here is a drive cycle that works well on Toyotas when trying to set the readiness monitors to pass an emissions test. I developed this myself by trial and error.
- Fuel tank at 1/2.
- Engine cold start idle for 10 minutes.
- Drive at highway speed 55-60 mph with steady throttle for 16 minutes.
- Return to idle for three minutes with engine running in park.
- Drive again at medium speed 40 mph for eight minutes.
- Return to idle for three minutes.
- Repeat next day.
One monitor requires a minimum temperature of 40 °F. If your climate is below this temperature at night the evap monitor will not complete. You must park the vehicle in a heated garage above 40° F for 12 hours, with the key off and fuel tank at 1/2, to run the evap monitor.
If there are pending malfunctions that have not yet turned on the malfunction light, the monitors will not become ready. In this case you must continue the drive cycles until the malfunction shows up.
It's helpful to have your own scan tool to know the status of the readiness monitors. If you don't have one and don't want to buy one, some auto parts stores will rent them to you.
Some auto parts stores like AutoZone will scan the codes and check your monitors free of charge.