Readiness Monitors Overview

The purpose of readiness monitors in a car is to self-test the car’s emission systems. Readiness monitors are self check routines that observe the performance of specific vehicle emissions control systems. Cars may perform up to 11 system tests; these are so called readiness monitors. The output of readiness monitors identifies whether the car’s computer has completed the required tests while the car is being driven. 

There are two different types of monitors: continuous and non-continuous. Continuous monitors are different in design from the non-continuous monitors. Continuous monitors are being constantly tested and evaluated by the car’s computer while the car is running. Conversely, the non-continuous monitors require certain conditions to be met before a test or series of tests can be completed. The conditions necessary for the car to run these self-diagnostic tests vary. Some monitors require that the car follows a predefined “drive cycle” routine. Some require two drive cycles due to the need for cool down and warm up periods in between. 

The OBD system monitors some functions every time you drive your vehicle, but only checks other functions under certain driving or operating conditions. Some checks are “continuous” and are ongoing all the time. Although continuous monitors are not part of the (NYVIP2) pass/fail criteria, they include:

   Comprehensive Component Monitoring to detect any major faults in engine sensors that
    may cause emissions to increase.

   Misfire Monitoring to detect ignition and fuel related misfires that
    may cause emissions to increase and/or damage to the catalytic converter.

   Fuel System Monitoring to detect changes in fuel mixture that may cause emissions to increase.