OBDII (On-Board Diagnostics II) not ready codes indicate that one or more of your vehicle’s emissions systems have not completed their self-diagnostic tests. These codes, often seen during smog or emissions inspections, can prevent your car from passing. This article explains what causes these codes and provides a potential solution for a Toyota MR2 with a 2AZ-FE engine.
What Causes OBDII Not Ready Codes?
Several factors can trigger Obdii Not Ready Codes, including:
- Recently Disconnected Battery: Disconnecting the battery resets the vehicle’s computer, clearing the diagnostic data.
- Cleared Diagnostic Trouble Codes (DTCs): Erasing DTCs also resets the system and requires the monitors to run again.
- Faulty Components: A malfunctioning sensor or part in the emissions system can prevent a monitor from completing its test.
- Incomplete Drive Cycle: Each monitor requires specific driving conditions to run its tests. An incomplete drive cycle prevents the monitors from completing.
Toyota MR2 (2AZ-FE Engine) Drive Cycle
A specific drive cycle is often needed to clear not ready codes. Here’s a potential drive cycle for a Toyota MR2 with a 2AZ-FE engine:
- Initial Idle: Start the engine and let it idle for 10+ minutes.
- Highway Driving: Drive at 43-56 mph for 3-5 minutes, maintaining engine speed between 900-3200 RPM.
- Idle: Stop and idle for 3-5 minutes.
- Repeat: Repeat steps 2 and 3 once.
- Moderate Driving: Drive at 40-55 mph for 3 minutes.
- City Driving: Drive at 35-45 mph for 7 minutes.
- Engine Off and Fuel Cap Release: Stop, turn off the engine, and release fuel tank pressure by removing and reinstalling the fuel cap.
- Immediate Driving: Start the engine and immediately drive at approximately 45 mph for 5 minutes.
- Stop-and-Go Driving: Drive at approximately 25 mph for 15 minutes, including at least two 30-second stops.
- Idle: Stop and idle for 2 minutes.
- Short Burst Driving: Drive at 25+ mph for at least 50 seconds, ensuring engine speed is above 900 RPM.
- Short Idle: Stop and idle for 40+ seconds.
- Repetitive Driving: Repeat steps 11 and 12 ten times.
If the readiness status remains incomplete, ensure all preconditions are met, turn the ignition off, and repeat the entire cycle.
Clearing OBDII Not Ready Codes
Completing the correct drive cycle often resolves not ready codes. However, if the codes persist, a diagnostic scanner, like the Autel MS309, can help identify the underlying issue.
By understanding the causes of OBDII not ready codes and utilizing the appropriate drive cycle, you can address this issue and ensure your vehicle passes emissions testing. Remember that persistent issues may require professional diagnosis and repair.
