Testing of Readiness Codes

If you take your vehicle for an emissions test shortly after the battery has been disconnected or gone dead, it may not pass the test.

This is because of certain ‘‘readiness codes’’ that must be set in the onboard diagnostics for the emissions systems. These codes are erased when the battery is disconnected, and set again only after several days of driving under a variety of conditions.

If the testing facility determines that the readiness codes are not set, you will be requested to return at a later date to complete the test. If you must get the vehicle retested within the next two or three days, you can condition the vehicle for retesting by doing the following.

1. Make sure the gas tank is nearly, but not completely, full (around 3/4).

2. Make sure the vehicle has been parked with the engine off for 6 hours or more.

3. Make sure the ambient temperature is between 40° and 95°F (4° and 35°C).

4. Without touching the accelerator pedal, start the engine, and let it idle for 20 seconds.

5. Keep the vehicle in Park. Increase the engine speed to 2,000 rpm, and hold it there until the temperature gauge rises to at least 1/4 of the scale (about 3 minutes).

6. Without touching the accelerator pedal, let the engine idle for 20 seconds.

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. Do not use the 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. Then drive in city/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. Make sure the vehicle has been parked with the engine off for 30 minutes.

If the testing facility determines the readiness codes are still not set, see your dealer.