Catalytic Converter Monitor (P0421)

Test requirements and procedure

1. All of the following requirements should be met when carrying out a drive test.
   1. Atmospheric temperature: -10°C (14°F) or more
   2. Condition of A/T: Selector lever position: D range
   3. A/C switch: OFF
2. One trip monitor will be completed by driving according to the steps below (from start to switch off). It will take 20 minutes.
   1. Start the engine, and accelerate gradually to 72 km/h (45 mph) or more.
   2. Preparation period; continue driving between 72 and 97 km/h (45 and 60 mph) for 300 seconds. Brake may be applied for this period if it continues for only a few seconds.
   3. Decelerate to 56 - 64 km/h (35 - 40 mph).
   4. Drive between 56 and 64 km/h (35 and 40 mph) at a constant throttle angle (by not moving the throttle pedal as much as possible) for 90 seconds or more during monitor.
   5. Decelerate with the throttle valve fully closed (Brake may be applied for this period). After the vehicle is being decelerated for ten seconds, accelerate gradually to 56 - 64 km/h (35 - 40 mph).
   6. Decelerate and stop the vehicle. Then turn off the ignition switch.