If your OBD2 scanner shows “not ready” for Catalyst or Evap System, it means your car hasn’t completed its drive cycle. This often happens after a battery disconnect or a recent repair. Completing a drive cycle allows your car’s computer to monitor these systems and ensure they’re functioning correctly. Here’s a step-by-step guide to completing a Toyota MR2 drive cycle (Engine Class 2AZ-FE), which may apply to other Toyota models as well:
Understanding the OBD2 Drive Cycle
A drive cycle is a specific series of driving conditions that allow the vehicle’s On-Board Diagnostics (OBD2) system to monitor emissions-related components. A “not ready” status indicates incomplete monitoring, preventing a smog inspection pass. Each vehicle and system has unique drive cycle requirements.
Toyota MR2 Drive Cycle Procedure (2AZ-FE Engine)
This procedure should be followed precisely to ensure accurate monitoring:
A. Initial Idle: Start the engine and let it idle for at least 10 minutes. This warms up the catalytic converter and other components.
B. Highway Driving: Drive at a consistent speed between 43-56 mph for 3-5 minutes. Maintain the engine speed between 900 and 3,200 rpm. This allows the system to monitor the catalytic converter under load.
C. Idle After Highway Driving: Stop and let the engine idle for 3-5 minutes. This allows the system to stabilize after highway driving.
D. Repeat Highway Driving and Idle: Repeat steps B and C once more.
E. Moderate Speed Driving: Drive at 40-55 mph for 3 minutes. This tests the system at different speeds.
F. City Driving Simulation: Drive at 35-45 mph for 7 minutes. This simulates typical city driving conditions.
G. Engine Off and Fuel Cap Reset: Stop the vehicle and turn off the engine. Release pressure in the fuel tank by removing and reinstalling the fuel cap. This resets the evaporative system monitoring.
H. Immediate Driving After Restart: Start the engine and immediately begin driving at approximately 45 mph for 5 minutes.
I. Low Speed with Stops: Drive at approximately 25 mph for 15 minutes, including at least two 30-second stops. This further tests the evaporative system.
J. Extended Idle: Stop and let the engine idle for 2 minutes.
K. Short Drive and Idle Repetition: Drive at 25 mph or more for at least 50 seconds, keeping the engine speed above 900 rpm. Then, stop and let the engine idle for at least 40 seconds.
L. Repeat Short Drive and Idle: Repeat steps K and L ten times. This allows for thorough system monitoring.
If the OBD2 Still Shows “Not Ready”
If the monitors haven’t switched to “complete” after this cycle, ensure all preconditions are met (no check engine light, proper fuel level). Turn the ignition off, and repeat the entire drive cycle (steps A through L).
Using an OBD2 Scanner
An OBD2 scanner can confirm the “not ready” status and verify completion of the drive cycle. Autel MS309 is a popular and affordable option for checking readiness status.
Conclusion
Completing a drive cycle is crucial for passing emissions tests. Following the correct procedure for your specific vehicle is essential. If you continue to experience issues, consult a qualified mechanic for diagnosis and repair.
