Honda Civic Owners Manual: Emissions Testing

Testing of Readiness Codes

Your vehicle has readiness codes as part of the onboard self diagnostic system.

Some States use these codes for testing to verify whether your vehicle's emissions components are working properly.

The codes may not be read properly if testing is performed just after the battery has gone dead or been disconnected.

To check if they are set, turn the ignition switch to ON *1, without starting the engine. The malfunction indicator lamp will come on for several seconds. If it then goes off, the readiness codes are set. If it blinks five times, the readiness codes are not set.

If you are required to have your vehicle tested before the readiness codes are ready, prepare the vehicle for retesting by doing the following:

1.  Fill the gas tank to approximately 3/4 full.
2.  Park the vehicle and leave the engine off for 6 hours or more.
3.  Make sure the ambient temperature is between 40F and 95F (4C and 35C).
4.  Start the engine without touching the accelerator pedal, and let it idle for 20 seconds.
5.  Keep the vehicle in P (continuously variable transmission) or N (manual transmission). Increase the engine speed to 2,000 rpm, and hold it there for about 3 minutes.
6.  Let the engine idle with your foot off the accelerator for 20 seconds.

*1: Models with the smart entry system have an ENGINE START/STOP button instead of an ignition switch.

7. Select a nearby, lightly traveled major highway where you can maintain a speed of 50 to 60 mph (80 to 97 km/h) for at least 20 minutes. Drive on the highway in D (continuously variable transmission) or 5th (manual). Do not use cruise control. When traffic allows, drive for 90 seconds without moving the accelerator pedal. (Vehicle speed may vary slightly; this is okay.) If you cannot do this for a continuous 90 seconds because of traffic conditions, drive for at least 30 seconds, then repeat it two more times (for a total of 90 seconds).
8.  Drive in city or suburban traffic for at least 10 minutes. When traffic conditions allow, let the vehicle coast for several seconds without using the accelerator pedal or the brake pedal.
9.  Park the vehicle and leave the engine off for 30 minutes.