Experiencing issues with your Honda Civic 2012 failing a smog test due to “readiness monitors not ready”? This is a common problem that can often be resolved with an OBD-II drive cycle. Modern vehicles like the Honda Civic 2012 utilize an On-Board Diagnostic system (OBD-II) to monitor various emissions-related systems. These systems have “readiness monitors” that need to be in a “ready” state to pass a smog test. If these monitors are not set, it often indicates that the car’s computer hasn’t fully evaluated these systems since the last time the codes were cleared or the battery was disconnected.
This article will guide you through the OBD-II drive cycle specifically designed to help your Honda Civic 2012 reset these readiness monitors, increasing your chances of passing your emissions test.
Understanding the OBD-II Drive Cycle
The OBD-II drive cycle is a specific set of driving conditions that prompts your Honda Civic 2012’s computer to run diagnostics on its emission control systems. By completing this cycle, you allow the system to test components like oxygen sensors, the catalytic converter, EVAP system, and EGR system, setting their respective readiness monitors to “ready”.
Important Pre-Conditions for Starting the Drive Cycle:
Before you begin the drive cycle, ensure the following conditions are met:
- Cold Start: The engine must be completely cold. Coolant temperature should be below 122 degrees Fahrenheit (50 degrees Celsius), and the ambient air temperature and coolant temperature sensors should be within 11 degrees Fahrenheit (6 degrees Celsius) of each other. A cold start is typically after the vehicle has sat for several hours, ideally overnight.
- Key Position: Do not turn the ignition key to the “ON” position before starting the engine. Doing so might prevent the heated oxygen sensor diagnostic from running correctly.
Honda Civic 2012 OBD-II Drive Cycle Steps:
Follow these steps precisely to complete the OBD-II drive cycle for your Honda Civic 2012:
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Initial Idle: Start the engine and immediately put the vehicle in “Drive” (for automatic transmissions) or in gear (for manual transmissions). Idle the engine for two and a half minutes (150 seconds). During this step, turn on the air conditioning (A/C) and the rear defroster to increase the engine load. This allows the OBD-II system to check the oxygen sensor heater circuits, air pump (if equipped), and EVAP purge system.
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Warm-up and Cruise: Turn off the A/C and rear defroster. Accelerate smoothly to 55 mph (88 km/h) using approximately half throttle. This allows the OBD-II system to check for ignition misfires, fuel trim adjustments, and canister purge functions. Maintain a steady speed of 55 mph for three minutes. During this constant speed phase, the system monitors the EGR system, air pump, oxygen sensors, and canister purge system more thoroughly.
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Deceleration: Safely decelerate (coast down) from 55 mph to 20 mph (32 km/h) without applying the brakes or depressing the clutch (for manual transmissions). This step allows the OBD-II system to check the EGR and purge functions during deceleration.
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Second Cruise: Accelerate again to 55 to 60 mph (88-96 km/h) at half throttle. This is another opportunity for the OBD-II system to re-check for misfires, fuel trim, and purge system operation under acceleration.
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Extended Cruise: Hold a steady speed between 55 to 60 mph for five minutes. During this longer steady-state drive, the OBD-II system focuses on monitoring the catalytic converter efficiency, misfires, EGR system, fuel trim, oxygen sensors, and purge functions.
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Final Deceleration and Idle: Decelerate (coast down) to a complete stop without using the brakes. Once stopped, the OBD-II system performs a final check of the EGR and canister purge systems.
After the Drive Cycle:
After completing the drive cycle, you should check the status of your OBD-II readiness monitors using an OBD-II scan tool. If the drive cycle was successful, the monitors should now be set to “ready”. You can then take your Honda Civic 2012 for a smog test.
Important Notes:
- This drive cycle procedure is a general guideline and may vary slightly depending on the specific year and sub-model of your Honda Civic 2012. Consult your vehicle’s repair manual or a more specific Honda service document for potentially more precise instructions if needed.
- If your readiness monitors are still not setting after multiple drive cycle attempts, there may be an underlying mechanical or electrical issue with your vehicle that is preventing the monitors from completing their diagnostic checks. In such cases, it is recommended to have your Honda Civic 2012 diagnosed by a qualified automotive technician.
- Always perform the drive cycle in a safe driving environment, obeying all traffic laws and speed limits.
By following these steps, you can effectively perform an OBD-II drive cycle on your Honda Civic 2012 and increase your chances of passing your next smog test by resetting your vehicle’s readiness monitors.
