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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 |
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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 |
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