OBD II Readiness Flags?

Retrieved From; http://www.smogtips.com/frequentlyaskedquestions.cfm

Depending on the year make and model of vehicle you own, this system is
different. If you own a 1996 or newer vehicle you more then likely own
a vehicle which is equipped with an On-Board Diagnostics system called
OBD II, as opposed to an OBD I system which older vehicles were
equipped with. The OBD II Diagnostic system is designed to monitor all
aspects of your engine's emission conditions and report this
information to a central database within it's computer. This
information is processed and checked against the computers
pre-determined values for various inputs levels and performance
patterns. If any problems are found, the computer will determine
whether to alert the driver or not. If a decision has been made to
alert the driver of an emissions problem, the "Check Engine" or "Engine
Malfunction" light will illuminate on the vehicle's dashboard. In more
serious emission conditions the computer may even begin to rapidly
flash the "Check Engine/Malfunction" light indicating to the driver,
that the vehicle needs immediate diagnosis/repair attention.

Now here's what the smog test has to do with the OBD II system...Your
vehicle is equipped with an OBD II computer AND a link to connect the
OBD II computer to a Smog Check Analyzer or Data Scan Tool (available
at most auto part stores). The OBD II link relays all "Check Engine"
conditions along with stored Trouble Codes with in the center database,
to the smog machine during the time of the smog inspection. If any
codes are present which cause the Check Engine light to illuminate
either regularly or intermittently, the vehicle fails the smog
inspection. Here's the tricky part, not all computer codes illuminate
the Check Engine light.

In fact I can say there are two types of codes, bad codes and good
codes. The good codes are the "Readiness Flags". These Readiness Flags
indicate that certain emissions systems which the OBD II computer has
been monitoring have PASSED the test, indicating that those systems are
working properly. Then there are the bad codes. The bad codes are
actual "Trouble Code". These codes indicate that the OBD II computer
has detected a problem with in the emissions system. The Trouble Code
will specifically indicate the component and problem which was found.
Newer vehicle's have very complex codes in the thousands.

A vehicle will fail the smog inspection if the proper "Readiness Flags"
are not set. A vehicle will also fail the smog inspection if any
"Trouble Codes" are present. So it is possible for a vehicle to fail
the smog inspection without the "Check Engine" light on. "Readiness
Flags" do not cause the "Check Engine" light to illuminate, but may
cause a vehicle to fail the smog test.

Now here's the fix... in order to set all the proper "Readiness Flags"
the OBDII system must complete at least one drive cycle (in some cases
two or three). A drive cycle is a sequence of internal tests which the
OBDII computer runs while your vehicle is being driven. This insures
all emissions systems are functioning properly. Only then will your
vehicle pass the smog inspection. A drive cycle usually requires one
week of driving.

I hope this information is helpful to you. If there is anything I can
help with in the future, don't hesitate to e-mail.

For more information you may want to locate a reputable smog service
center in your area by simply typing in your zip code in the Smog Shop
Locator search section at www.smogtips.com

Sincerely,
Alec - SmogTips Support http://www.smogtips.com






RottenRocky wrote:
> Hey all!
>
> Can anyone point me toward some info on OBD II readiness info? We are
> implementing OBD II testing on 96 and newer vehicles in our I/M
Program. I
> would really like the enable criteria or drive cycle to have the
readiness
> flags cleared. Also any makes & models that may have problems. Any
info
> would be appreciated.
>
> Thanks,
>
> Tracy Hammond

On 31 Jan 2005 15:19:43 -0800, "TheSmogTech"
> wrote:


As a footnote, you can go into I/M Mode on some scantools, e.g. Actron
9145, and watch all the flags as they set to OK, Ready, Passed. Then
you just drive into the inspection bay with a _guarantee_ you're going
to get validated.

Lg


>Retrieved From; http://www.smogtips.com/frequentlyaskedquestions.cfm
>
>Depending on the year make and model of vehicle you own, this system is
>different. If you own a 1996 or newer vehicle you more then likely own
>a vehicle which is equipped with an On-Board Diagnostics system called
>OBD II, as opposed to an OBD I system which older vehicles were
>equipped with. The OBD II Diagnostic system is designed to monitor all
>aspects of your engine's emission conditions and report this
>information to a central database within it's computer. This
>information is processed and checked against the computers
>pre-determined values for various inputs levels and performance
>patterns. If any problems are found, the computer will determine
>whether to alert the driver or not. If a decision has been made to
>alert the driver of an emissions problem, the "Check Engine" or "Engine
>Malfunction" light will illuminate on the vehicle's dashboard. In more
>serious emission conditions the computer may even begin to rapidly
>flash the "Check Engine/Malfunction" light indicating to the driver,
>that the vehicle needs immediate diagnosis/repair attention.
>
>Now here's what the smog test has to do with the OBD II system...Your
>vehicle is equipped with an OBD II computer AND a link to connect the
>OBD II computer to a Smog Check Analyzer or Data Scan Tool (available
>at most auto part stores). The OBD II link relays all "Check Engine"
>conditions along with stored Trouble Codes with in the center database,
>to the smog machine during the time of the smog inspection. If any
>codes are present which cause the Check Engine light to illuminate
>either regularly or intermittently, the vehicle fails the smog
>inspection. Here's the tricky part, not all computer codes illuminate
>the Check Engine light.
>
>In fact I can say there are two types of codes, bad codes and good
>codes. The good codes are the "Readiness Flags". These Readiness Flags
>indicate that certain emissions systems which the OBD II computer has
>been monitoring have PASSED the test, indicating that those systems are
>working properly. Then there are the bad codes. The bad codes are
>actual "Trouble Code". These codes indicate that the OBD II computer
>has detected a problem with in the emissions system. The Trouble Code
>will specifically indicate the component and problem which was found.
>Newer vehicle's have very complex codes in the thousands.
>
>A vehicle will fail the smog inspection if the proper "Readiness Flags"
>are not set. A vehicle will also fail the smog inspection if any
>"Trouble Codes" are present. So it is possible for a vehicle to fail
>the smog inspection without the "Check Engine" light on. "Readiness
>Flags" do not cause the "Check Engine" light to illuminate, but may
>cause a vehicle to fail the smog test.
>
>Now here's the fix... in order to set all the proper "Readiness Flags"
>the OBDII system must complete at least one drive cycle (in some cases
>two or three). A drive cycle is a sequence of internal tests which the
>OBDII computer runs while your vehicle is being driven. This insures
>all emissions systems are functioning properly. Only then will your
>vehicle pass the smog inspection. A drive cycle usually requires one
>week of driving.
>
>I hope this information is helpful to you. If there is anything I can
>help with in the future, don't hesitate to e-mail.
>
>For more information you may want to locate a reputable smog service
>center in your area by simply typing in your zip code in the Smog Shop
>Locator search section at www.smogtips.com
>
>Sincerely,
>Alec - SmogTips Support http://www.smogtips.com
>
>
>
>
>
>
>RottenRocky wrote:
>> Hey all!
>>
>> Can anyone point me toward some info on OBD II readiness info? We are
>> implementing OBD II testing on 96 and newer vehicles in our I/M
>Program. I
>> would really like the enable criteria or drive cycle to have the
>readiness
>> flags cleared. Also any makes & models that may have problems. Any
>info
>> would be appreciated.
>>
>> Thanks,
>>
>> Tracy Hammond