Is your vehicle "READY" for its Air Care inspection? "Readiness Monitors" Explained

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What is a “Readiness Monitor"?

Most light-duty 1998-and-newer model year vehicles are equipped with an electronic emission control monitoring system known as On-Board Diagnostic (OBD). This system continuously monitors, tracks and stores information about the emission control devices and emission-related engine components on a vehicle. These self checks are referred to as "Readiness Monitors."

Most vehicles have between seven and 11 monitors, or self checks, that the computer system performs. The computer looks for specific speeds, temperatures, levels, and pressures from various sensors. When the vehicle’s computer receives the a signal from a particular sensor, it runs the readiness monitor check. Once the vehicle’s computer completes the check of a monitor, the readiness system status is set to “Complete” or “Ready." If the vehicle has not completed the self check, the status is reported by the computer as “Not Complete” or “Not Ready."

When a vehicle's emissions are inspected at an Air Care Colorado emissions inspection station, the vehicle's readiness monitors must be set to "Ready."

What causes a vehicle to be “Not Ready”?

Unset readiness monitors do not necessarily mean that anything is wrong with the vehicle. It simply means that the vehicle has not had a chance to complete all of its self checks to confirm that the vehicle is operating properly. There are several reasons why a vehicle may be “Not Ready." The most common are:

  • Recent vehicle repairs or maintenance in which diagnostic trouble codes have been cleared with an OBD scan tool
  • A recently disconnected or replaced battery
  • Pending problem that has not yet illuminated the "Check Engine" or Malfunction Indicator Light (MIL)

What happens if a vehicle is presented for an inspection and it is "Not Ready"?

If monitors are not "Ready," it is impossible to know if a vehicle is operating properly because the self checks have not been completed.

Vehicles between eight and 11 model years old require an OBD inspection. If a vehicle computer displays "Not Ready" codes during its initial inspection, the vehicle will either:

  • Automatically be inspected with an alternate I/M 240 dynamometer test, or;
  • If the vehicle cannot be tested on a dynamometer, due to size or other restrictions, it will be rejected from testing and sent away until more driving is completed and the monitors are set to "Ready."

If a vehicle returns for a reinspection, after a failed test, and the Readiness Monitors are set to "Not Ready," the vehicle will be sent away until more driving can be completed and the monitors are set to "Ready."

How does a vehicle become "Ready"?

Vehicles perform self checks during normal courses of driving. Vehicle drive cycles differ, but generally driving for a week, give or take a few days, should be sufficient for the computer to conduct all of the necessary self checks. However, to be certain, contact your dealership or repair shop to determine the manufacture's specific drive cycle for your vehicle.