OBD II Monitor Readiness – Drive Cycle GM

The following is the recommended driving cycle for General Motors.

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

  1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
  2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge “No Flow”, Misfire and if closed loop is achieved, Fuel Trim.
  3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
  4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
  5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
  6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
  7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
  8. Decelerate. This will perform the same diagnostics as in step 5. Again, don’t press the clutch or brakes or shift gears.

Reprinted on OBDII web site courtesy of General Motors © GM

67 Replies to “OBD II Monitor Readiness – Drive Cycle GM”

  1. Seth

    Can I do the steps separate without having to do the full drive Cycle? Only the Cat and Evap are not ready and I live in the mountains. Also are other steps necessary for the evap and cat tests to run? Been going through hell trying to find a good straight flat road with no traffic and get the cold start while waiting 8 friggin’ hours each time.
    Thank you

    Reply
    • Julius

      The Bureau of Automotive Repair recognizes that competing the EVAP monitor can be difficult, so your 2003 Silverado will pass the OBD II portion of the smog inspection with an incomplete EVAP monitor if the “Check Engine” (MIL, Service Engine…, etc) is not commanded on, and all other monitors are complete.

      That said, yes, you can complete the steps separately as long as all other pre-requisites for completing the monitor have been met. For example, on a 2003 Chevy C1500 2WD truck with a 4.8L V8 – VIN V), the following conditions would have to be met before attempting to complete the catalyst monitor:

        – The barometric pressure more than 74 kPA
        – Engine coolant temperature 160-248F
        – Intake air temperature 5-167F
        – Engine in closed loop fuel control
        – engine has run for 6-8 minutes off idle in order to initiate test
        – battery voltage 11-18 volts

        Once criteria has been met:

        – Turn off all accessories, including the A/C and the blower fan.
        – Start the engine, and allow the engine to idle
        – Accelerate at part throttle to 55mph and maintain speed for 5 minutes
        – Decelerate to 0 mph
        – Idle for two minutes with the brake depressed, transmission in drive (Or on a manual transmission, in Neutral with the clutch pedal depressed

      Again, meeting all the above criteria can be a challenge. Depending on your engine size, a different procedure may apply.

      Reply
      • joaquin

        I have a hummer h2 no codes replaced all 4 o2 sensors with ac delco brand drove it for 100+ miles and still not ready what should I do now? just keep driving?

        Reply
        • dewok Post author

          Hi Joaquin,

          I’m assuming that the vehicle was in a “not ready” status prior to the repair. I would check if the vehicle’s firmware is up-to-date. We smog check a decent number of H2 Hummers. I don’t recall seeing a pattern of 02 monitor issues with Hummers.

          You can also try clearing all the adaptives via a scan tool and starting the drive cycle from scratch. We have found that this can work on stubborn vehicles sometimes.

          Reply
        • ponce

          thanks for the advise,, but I took the vehicle to the dealer to get a diagnostic report and dis the drive cycle a few times drove it about 500 miles and nothing, the evap 02 and the cats still incomplete, replaced the cats and had the dealer do a flash on the ecm drove it for another 400 miles and still nothing. At this point I don’t know what to do?? this are the parts a replaced so far without getting a code
          o2 sensors all 4
          camshaft sensor
          oil pressure sensor
          knock sensors and harness
          pedal sensor
          throtle body unit
          air filter
          fuel filter
          fuel pump
          exhaust manifold gaskets
          spark plugs
          battery
          motor oil and tranny
          all with oem parts ac delco is there anything else that I need to replace to help set my monitors??

          Reply
          • Jason

            In Illinois it’s legal for you to do all tests and if it still comes up as incomplete you can fill out a form. The form described as best I can is just stating you agree to have fixed the problems to do with the smog system and have to have spent atleast $450 on repairs. Either from a mechanic or you can do it yourself.

  2. Jim Musick

    I also live in the mountains but the only road to try to do the cold start is a major why so the coasting down to 20 mph is Almost impossible. any suggesting its a Chevy silverado 2005 5.3 vortex 4×4

    Reply
    • dewok Post author

      Hi Jim,

      You may need to drive in a different location. Beyond driving conditions, I have read that some vehicles have difficulty settings monitors at higher elevations.

      Reply
    • Staci

      That’s my exact dilemma.. 2004 Chev Tahoe OBD2 is not ready due to recent mechanical work that cleared the computer.. I can/did all the steps this weekend but I can only drive 55mph on the HWY and coasting down to 20 MPH is impossible not to mention a death trap on these LA freeways..

      Reply
    • dewok Post author

      Hi Ediwn,

      It depends on the particular vehicle. Some vehicles can set the oxygen sensor heater monitor simply by warming up in park from a cold start.

      Danny
      Just Smogs

      Reply
    • John

      Oxygen heater requires a cold start and the AC switch and rear defrost need to be on at the same time. It should go complete within 2.5 minutes.

      Reply
  3. john

    When doing GM s drive cycle I noiticed the cat didn’t complete until you really gun it up to 55 you know punch it… I guess it checks flow making sure it has no backpressure, as to, Its not plugged.. so during the test punch it up to 55

    Reply
  4. Robert

    I got the same thing ..cat “not ready”and “evap” not ready on my 03 GMC sierra. I’ve put$140.00 in fuel so far and drove it like there saying with atleast 5 drive cycles and still got nothing. I’m within 150 dollars of my registration costing me 2,000 dollars. This has to be one of the biggest jokes I’ve come across. I’ve got no check engine light on after 350 miles so what now???? I just keep paying until everything is replaced and then have my truck junked because of this

    Reply
  5. Chris Oliphant

    I have a 2010 GMC box truck (cutaway) that will not clear the EVAP module in the OBD11. No codes, no pending codes everything else has cleared and I’ve followed all the recommended procedures to clear the EVAP module. Truck has been driven over 600 miles. Of course the rules were changed on July 1st where all modules had to clear before the truck would pass smog. Prior to that if the EVAP had not cleared we were good to go.

    Any thoughts regarding this. Any help would be appreciated.

    Reply
    • dewok Post author

      Hi Chris,

      The only thing that has changes in regards to the California smog check is that California now fails vehicles that have a permanent DTC stored. As of right now (August 2019), your vehicle will still pass a smog check with the EVAP monitor incomplete (As long as all other monitors are complete and there are no stored permanent DTC(s).

      The only way to clear a PDTC is to fix the underlying problem with the vehicle that originally caused the PDTC and its corresponding DTC to set, and then allow the vehicle sufficient drive time to re-run the monitor that identified the problem in the first place. When the monitor runs without identifying a problem, the PDTC will clear itself.

      So if there is a permanent DTC, you just have to keep driving the vehicle until it clears itself.

      Reply
      • Chris Oliphant

        Ah, there’s the rub. As of July 1st ALL PDTC’s have to clear, including the EVAP module, before it will pass smog.

        After much trial and error (ambient temperature appears to plays a major role here) the EVAP finally cleared. It took me 720 miles but I believe I can shorten that if I do it better.

        It wouldn’t matter if it was my vehicle but I sell (we’re a licensed dealer) the off rental box trucks for Uhaul here in Fremont and of course I need a smog it before I can sell it within CA.

        I have one more coming up where the OBD codes have been erased after repairs. I just hope from what learnt doing this one I can save some time and gas getting everything to set.

        Thanks for your help

        Chris

        Reply
  6. Jack

    I have a 2005 Chev Tahoe 5.3 —I have no stored codes—-no lights—but cat monitor will not ready for test. Drive over 500mi—high octane gas—tried to follow procedures for readying monitor but no luck so far. Any help appreciated.

    Reply
    • dewok Post author

      Hi Jack,

      Chevys usually set the readiness monitors if you follow the drive cycle procedure. We have found that some GMs with thermostat/cooling system issues are unable to warm up properly and in turn will not complete the catalyst monitor. Other times the catalytic converter(s) are not “efficient” enough to set the monitor to ready but at the same time not bad enough to set a trouble code.

      Reply
  7. OSCAR. C.

    Will this drive cycle still work if the AC IS BROKEN? HEATER WORKS FINE!ALSO DOES THE VEHICLE NEED TO HAVE A CERTAIN AMOUNT OF FUEL FOR THE MONITORS TO BE ABLE TO BE RESET (EVAP,CATYLIST AND O2 HEATER) ? THE REST OF THE MONITORS ARE READY. ITS A 2000 1 TON 3500 4 DOOR CREW CAB truck.

    Reply
    • dewok Post author

      Hi Oscar,

      Most vehicles require between 1/4 and 3/4 of fuel for the EVAP monitor to complete. I don’t believe that the broken A/C system will prevent the readiness monitors from completing on your vehicle.

      Reply
  8. kathy lee

    I have a 2014 buick regal all readiness monitors are set except for the oxygen senor ( not the heated one) I like to do a seprated test I just dont know which one to do– can you let me know which one too do

    Reply
    • dewok Post author

      We have found that when running drive cycles on vehicles with manual transmissions, it is best to keep RPM under 2500 by driving easy and shifting often. This might not be true for all vehicles/drive cycles.

      Reply
        • dewok Post author

          Hi Kathy,

          The EVAP monitor may not complete with a fuel tank above 3/4s. Remember if all other monitors are complete except EVAP, your vehicle can still pass a California smog check.

          Reply
          • Kathy

            Thank you for your reply. It is my Secondary Air Monitor that is incomplete (and is STILL not clearing, three weeks later).

            So far my mechanic has changed the oxygen sensor after the CC (Bank 1, sensor 2) and has replaced both air injection check valves. He also had the computer cleared… and has driven it through the “cycle” many many times (has put about 400 miles on my 2001 Tahoe).

            It is STILL not running and clearing that monitor.

            Any further suggestions? Thank you, in advance!

          • dewok Post author

            Hi Kathy,

            It sounds like your mechanic knows what he is doing.

            There is a systematic process of diagnosing vehicles. For example: check if the air pump is activating when it is suppose to? Are all the components in the Air Injection system working correctly? Most vehicles use the rear O2 sensor to monitor the air pump. Are both O2 sensor responding properly?

            Without having the vehicle in our shop, we are limited on what we can suggest.

            Good luck!

          • kathy lee

            my car has passed smog yeahhhh it was the time of day that cos it to fail to do the drive cycle correctly its very important that car the temp in the morning be under 50 degree (they really mean this or the test will not run) when we took it on the highway at the correct temp it passed plus I brought a obii scanner that was connected to my car while we was on the freeway that “chime in” when the test was complete. I recommend that people buy one if you can afford it, https://www.amazon.com/Actron-CP9690-AutoScanner-Enhanced-vehicles/dp/B011ICD2WQ/ref=sr_1_1?dchild=1&keywords=Actron+CP9690&qid=1616082485&sr=8-1

          • kathy lee

            typo—its very important that the car temperature in the morning be under 50 degree(they really mean this or the test WILLNOT run) on newer model cars check your car year in model to be sure

  9. Daniel

    All my checks have passed except the catalytic sensor for my 2005 Honda accord. Do I have to drive at 50-60mph for 20min as directed by the car manual or can I drive faster at 70-80mph?

    Reply
    • dewok Post author

      To complete the catalyst monitor on your 2005 Honda Accord follow instructions directed by Honda: drive a steady 55mph for 20 minutes.

      Reply
  10. Sal

    2009 GMC SIERRA. No pending codes, no CEL, LTFT healthy. Oxygen Sensor monitor will not ready. I am unable to register the vehicle in California. 🙁
    Thanks liberals.

    Reply
    • demian martin

      I have a 2008 Saab 9-5. I have been working on getting the evap cycle to run. I have found no specifics, just generalized GM info. And the GM info is not consistent. As you mention above different engines need different procedures. Mt Tech2 cannot even tell if the tests have been run. Fortunately a more generic tool can. Finally it seems I may need 6 cycles but if I’m doing it wrong that doesn’t help since I still cannot tell.until 6+ failed attempts. Is this typical of GM?

      Reply
  11. Andrew Smith

    How the hell are you supposed to decelerate to 20 mph from 55 mph in a manual transmission without using the clutch or downshifting? Where are you supposed to even do that at? People fly up on your ass if you go 1 mph under the speed limit…. I tried this 13 years ago in a 2000 Chevy S10. Had a very nasty accident. Truck was totaled.

    Reply
      • shawn

        on 2014 chevy impala limited lt from changing battery took 1 day to take out 2 mon second day 2 more trying drive cycles i was approaching maintenance period asked chevy how to get o2 and evap cleared cuz i had driven like 800 miles they said drive it, i was like i did 800 dam miles he said for 02 and evap go out on highway no a/c no drive cycles they send ppl out and drive on highway until they set, well i drove 3 more days 3 cold start cycles as well and finally at 1600 miles o2 sensor finally set, drove back home went shopping car has over 1700 miles still needs evap going to try cold start and another cycle to see if i can get evap done before tomorrow because its last day of month and ny safety inspection due it will pass here with evap not working but i dont want it on my carfax if its at all possible if i can get evap ready today and tomorrow

        Reply
  12. Peter Lauridsen

    I replaced the battery in my 2000 Silverado and after completing the drive cycle, everything shows ready except the EVAP & MIL both show inc. Do you have any suggestions to correct this?

    Reply
    • dewok Post author

      Hi Peter,

      An incomplete EVAP monitor is normal at this point and this will not prevent your Chevy from passing a CA smog check. As for the MIL incomplete, I’m not certain that this is accurate.
      MIL is an acronym for Malfunction Indicator Light (same as check engine light).

      Unless there are stored fault codes and the MIL is illuminated, most likely your Silverado is ready for inspection.

      Reply
      • Peter Lauridsen

        Thank you for the quick response, I’m in Colorado but the same rules should apply. As for the MIL, the check engine light is not on, the ABS is.

        Reply
        • dewok Post author

          Bring your truck to an inspection station and have them double check monitors. I’m sure it’s good to go!

          Reply
      • Dawn ash

        I can’t get my 04 Chevy Silverado to pick up on its evap and catalyst monitors and I’ve done drive cycle alot and put about 600 miles on truck still nothing

        Reply
        • dewok Post author

          Hi Dawn,

          Focus on the catalyst monitor. No need to worry about EVAP.

          If everything is working correctly and the vehicle has no exhaust leaks, monitors for an 04 Chevy are usually relatively easy to complete. Don’t forget to double check the vehicle is warming up properly (thermostat is operating correctly).

          CAT monitor is completed at a steady 55 mph.

          Good luck,
          Danny
          JUST SMOGS+

          Reply
  13. Patty

    I am still trying to get the CAT sensor to set on my 2002 corvette. The car has about 68000 miles. I have been trying to do all of the drive cycle each time. Can I get away with something more specific to just get the CAT set? We have a mountain road where I can and do travel at 55mph for about 5 minutes. I know I have done this more than five times. I’ve probably driven a total of 200 miles since my battery was plugged back in. Each drive is about 15 miles each way. Should I just take the car on a long day trip?

    Reply
    • dewok Post author

      Hello Patty,

      Elevation can possibly play a roll in not allowing a particular monitor to set.

      A steady 55 mph for 5 minutes should set the CAT monitor for your Chevrolet.

      If this is not working, than yes, take the vehicle on a road trip. I also recommend purchasing an OBD scanner to read the monitors real time as you are driving.

      Good luck!

      Reply
  14. Dorothy

    A friend of mine brought a 2010 Nissan Altima from Chicago a couple of years ago and had a new exhaust manifold, O2 sensor and catalytic converter installed to comply with California regulations. He does not use the car and it has been sitting in his garage, so wants to sell me the car, but we cannot get the O2 sensor and catalytic converter to complete their checks–the OBD scanner shows both as “Incomplete.” We have driven extensively (400 miles) and followed the owner’s manual as much as possible to do highway and stop-start city driving (although, frankly, both have been a challenge when surrounded by unpredictable traffic and may need to go faster/slower than recommended). Is there not some other way to complete these checks so I can register the car?

    Reply
    • MARIE LOVE

      warm car up 15 min drive the car on freeway in the morning temperature outside MUST be below 50 degree from San Francisco to San mateo keep car speed at 55

      Reply
  15. Travelingman

    I have a 2005 GMC Yukon that did not pass smog the first time. Noticed the engine light was on ( automatic fail) and We changed the oxygen sensors. I came home and the next day or so drove it for a long time. I noticed the engine light was now off and stays off. I assume it reset now. We bought and used a OBDII and used it to check again, we cleared any codes. I get a green check on the OBDII but wee see a red X on EVAP. Will that stop us from passing smog?

    Reply
    • dewok Post author

      Currently in California you are allowed to have an incomplete EVAP monitor and still pass smog.

      Reply
  16. Brian

    2008 chevy colorado. Disconnected battery to do some work then smogged a few days later and failed as monitors wern’t ready. Drove over 100 miles and all monitors reset except 02 sensor. Could not get it to reset after driving it more. Replaced both 02 sensors and have driven close to 100 miles doing different aspects of the drive cycle. Haven’t been able to successfully complete the 55mph/60mph cruise and coast down to 20mph (hard to do in socal). Is that portion of the drive cycle the only thing that will ready the 02 sensor monitor? I”m 3 weeks away from registration due and getting worried this thing will never reset.

    Reply
    • dewok Post author

      Hi Brian,

      For Chevys, the O2 sensor monitor generally completes by cruising at highway speeds. We usually drive 55 mph. Don’t forget to make sure the AC is off and you allow the vehicle to warm up for about 15 minutes at idle from a cold start.

      As for your pending DMV due date, simply pay for it on time to avoid financial penalties. Once your Colorado passes the smog check, the DMV will complete the registration.

      Good luck!

      Reply
  17. Dannielle

    I have a 2013 Chevy Cruze LT only monitor I need completed is the o2 sensor, how do I get that one to complete all codes have been fixed & cleared even a new o2 sensor over a month ago. I’ve read getting speed up to 55mph for 5mins & then coasting down to 20mph without touch brake or gas but idk where to even do that as that’s impossible on the highway.

    Reply
    • dewok Post author

      Hi Dannielle

      It’s not uncommon to have trouble setting O2 monitors.

      Sounds like you’re doing everything correct. Don’t forget to allow the vehicle to warm up at idle and don’t have the AC running. I’m not sure if this matters for your 2013 Chevy, but we do it just in case.

      Perhaps someone else in the community may be able to provide input.

      Reply
    • Kelly

      20mph is mis/overstated. The ACTUAL recommendation as tested on a dyno is coast down 20mph from previous stable speed (so if you were doing 60mph coast down about 10 seconds off the accelerator to 40mph, then you can climb back up to 60+), If you try and coast down to 20mph on a freeway you will get rear ended or shot at. The only thing being checked is the decel fuel changes and sensor measurement of load variation and the recovery when you accel again, all the way to 20 is not a requirement for any of monitors.
      (On some cars all the way to 20 is a stated requirement to learn CKP position, but not for Smog monitors)
      Dont anyone forget, these all will eventually run with NORMAL driving. Special drivecycles are simply to try and speed up completion. However when customer say theyve driven the car over 2000 miles and a monitor still is not complete AND there are no codes set either, this is not a drivecycle problem, this is a problem with the vehicle preventing completion (or required conditions of completion) from being achieved or maintained

      Reply
  18. JPNYC

    Hi, I have a 2009 GMC Yukon SLT. No Engine Codes, not ready for emissions test (EVA & O2S Monitor’s drive cycles are not complete). Inspection expired 7/28 in NY, I have until 8/30 to get it inspected in order to renew registration and I’ve been at it all month! Please help…it was 4 before including Cat Converter but even that’s been clearer now…what can I do to pass?

    Thanks in advance guys

    Reply

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