strex SP50 - OBD II Readiness Monitors Explained

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OBD II Readiness Monitors
Readiness Monitors are indicators used to nd out if all of the emissions components
have been evaluated by the OBD II system. They are running periodic tests on specic
systems and components to ensure that they are performing within allowable limits.
Currently, there are eleven OBD II Readiness Monitors (or I/M Monitors) dened by
the US Environmental Protection Agency (EPA). Not all monitors are supported by
all vehicles and the exact number of monitors in any vehicle depends on the motor
vehicle manufacturer’s emissions control strategy.
Continuous Monitors:
Some of the vehicle components or systems are continuously tested by the vehicle’s
OBD II system, while others are tested only under specic vehicle operating
conditions. The continuously monitored components listed below are always ready:
1. Misre
2. Fuel System
3. Comprehensive Components (CCM)
Once the vehicle is running, the OBD II system is continuously checking the above
components, monitors key engine sensors, watches for engine misre, and monitors
fuel demands.
Non-Continuous Monitors:
Unlike continuous monitors, many emissions and engine system components require
the vehicle to be operated under specic conditions before the monitor is ready.
These monitors are termed non- continuous monitors and are listed below:
1. EGR System - Exhaust Gas Recirculation for reducing greenhouse gases.
2. O2 Sensors - Monitor and adjust air/fuel mixture.
3. Catalyst - Reduces exhaust emissions.
4. Evaporative System - Monitors the integrity of the fuel tank system.
5. O2 Sensor Heater - Brings the O2 sensor to the correct operating temperature.
6. Secondary air - Reduces the exhaust emissions.
7. Heated Catalyst - Brings catalyst to correct the operating temperature.
8. NC system - Monitors the system for Freon leaks.