Ready or Not

September 4, 2020

Setting The Record Straight On Readiness Monitors And On-Board Diagnostics (OBDII) Inspections

Readiness Monitor Status

Readiness Monitor Status is NOT the same as Diagnostic Trouble Codes (DTCs). Readiness represents whether or not the emissions control system in question has been evaluated. This evaluation tests for system functionality and, if a problem is detected, a DTC will be stored in the on-board computer.

What does "Ready" vs. "Not Ready" status mean?

  • Ready - the OBDII system has checked this emissions control system.

  • Not Ready - the OBDII system has NOT checked this emissions control system.

  • N/A or N/S - the OBDII system is not required to check this emissions control system.

Disconnecting the battery is the most common reason why monitors are "Not Ready"

Some reasons for disconnecting the battery are:

  • Tune-ups and other engine repairs

  • Dead battery replacement

  • Car radio installations

  • Car alarm installations

Where is Readiness Monitor Status on the Vehicle Inspection Report (VIR)?

The Emissions Tests Results section of the VIR shows the status of each readiness monitor.

Remember Effective October 15, 2008:
For vehicles year model 2001 and newer,  we allow one (1) non-continuous monitor to be "Not Ready" and still pass the test, but two (2) or more "Not Ready" readings will cause the vehicle to fail.

For vehicles year model 1996 – 2000, we allow two (2) non-continuous monitors to be "Not Ready" and still pass the test, but three (3) or more "Not Ready" readings will cause the vehicle to fail.

Emissions Test Results
MIL CMND Status: OFF Misfire: Ready Heated Cat: N/S 02Sensor Not Ready
  Fuel Sys: Ready Evap: Ready 02 Sensor Htr: Ready
MIL Engine On: PASS Comp Cmpnt: Ready 2nd Sys: Ready EGR Sys: Not Ready
MIL Engine Off: PASS Catalyst: Not Ready Air Cond: N/S    
Overall Result - FAIL            

Changing the monitor(s) to "Ready"

  • In order to get the OBDII system to set the monitors to "Ready," the vehicle needs to be driven through a drive cycle/drive trace.

  • If you don't have access to drive cycles/drive traces, they should be available from a qualified service technician or dealership.

  • With a generic OBDII scan tool*, verify the monitors are "Ready" before returning the vehicle to the customer.

*Vehicle manufacturer specific scan tools must be in the global OBDII or generic OBDII mode to display readiness monitor status.

If the vehicle has DTCs stored, and the MIL is commanded on:

  • The vehicle will need repairs to correct the malfunction before it will pass the OBDII inspection.

  • If you've cleared the DTCs (using a scan tool or disconnecting the battery), monitors will reset to "Not Ready".

  • Driving the vehicle through the drive cycle/drive trace will set the monitors back to "Ready" and verify that the repairs were effective.

  • With a generic OBDII scan tool, verify the monitors are "Ready" before returning the vehicle to the customer.

IMPORTANT!!!

Automobile repair technicians need to check for service and recall bulletins that may apply to certain vehicles with readiness issues.