The test itself
Readiness monitors and “not ready” results
Updated Oct 7, 2026 · sources read Oct 7, 2026 · 2 official sources quoted
Short answer
A 2001 or newer vehicle may have one non-continuous monitor “not ready” and still pass; two or more fail. A 1996-2000 vehicle may have two; three or more fail. Monitors usually show “not ready” after the battery was disconnected or codes were cleared, and driving a drive cycle sets them again.
What a readiness monitor is
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.
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.
There are three (3) continuous monitors that are always Ready: Misfire, Fuel System, and Comprehensive Components.
How many may be not ready
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.
The Emissions Tests Results section of the VIR shows the status of each readiness monitor.
Why monitors reset
Disconnecting the battery is the most common reason why monitors are "Not Ready"
DPS names these common reasons for disconnecting a battery:
Tune-ups and other engine repairs Dead battery replacement Car radio installations Car alarm installations
These non-continuous monitors are considered Ready until either DTC's have been cleared with a scan tool or if battery power has been disconnected, then the monitors will reset back to Not Ready
If you've cleared the DTCs (using a scan tool or disconnecting the battery), monitors will reset to "Not Ready".
Reading DPS’s sample report
DPS’s readiness page prints a sample “Emissions Test Results” section. The check-engine light is not commanded on, yet three non-continuous monitors (oxygen sensor, EGR system and catalyst) read “Not Ready”, and the overall result is a fail. Three is too many for any model year: a 2001 or newer vehicle may have one monitor not ready and a 1996-2000 vehicle two. With no trouble code stored, the usual next step is to drive the vehicle through a drive cycle, since “Not Ready” only means the system has not been checked yet.
MIL CMND Status: OFF
02Sensor Not Ready
EGR Sys: Not Ready
Catalyst: Not Ready
Overall Result - FAIL
Getting them back to ready
In order to get the monitors set back to Ready, the vehicle must be driven through a drive cycle, which is a combination of city/highway driving for a set period of time.
DPS says the drive cycle for a vehicle should be available from a qualified service technician or a dealership, and that a generic OBD II scan tool shows the monitor status before you go back to the station.
If you don't have access to drive cycles/drive traces, they should be available from a qualified service technician or dealership.
The vehicle will need repairs to correct the malfunction before it will pass the OBDII inspection.
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.
Clearing codes right before a test does not help: it resets the monitors to “not ready”, which can fail the test on its own.
A sensible order after a battery change or a repair: drive the vehicle through a drive cycle of city and highway driving (a technician or dealership can tell you the cycle for your vehicle); if you or a shop have a generic OBD II scan tool, check that the monitors read “Ready” (or at most one “Not Ready” on a 2001 or newer vehicle); then go to the station. If a monitor never sets, a technician should check for service and recall bulletins, which DPS says can apply to some vehicles with readiness issues.
Automobile repair technicians need to check for service and recall bulletins that may apply to certain vehicles with readiness issues.
Questions
How many monitors can be “not ready” on a 2001 or newer car?
One non-continuous monitor. Two or more not ready fails the test.
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.
I just replaced my battery. Will my car fail?
It may, if you test right away: disconnecting the battery resets the monitors to not ready. Drive it through a drive cycle first so the monitors set again.
Sources
- Texas DPS, Ready or Not (FAQ on readiness monitors)page as published Apr 19, 2026 (archived copy), read Oct 7, 2026
- Texas DPS, Emissions Testing (FAQ)page as published Sep 10, 2026 (archived copy), read Oct 7, 2026
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