Ready or Not
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 (DTC's). 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
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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's 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's will cause the vehicle to fail.
|Emissions Test Results
|MIL CMND Status: OFF
||02 Sensor Htr:
|MIL Engine On: PASS
|MIL Engine Off: PASS
|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 DTC's 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 DTC's (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.
Automobile repair technicians need to check for service and recall bulletins that may apply to certain vehicles with readiness issues.
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