Check OBD II Monitor Readiness Without A Scan Tool

Image of instrument cluster including "Check Engine" lightIt is possible to check OBD II monitor readiness on many late model vehicles without connecting a scan tool. This can often be necessary in order to determine if your car is ready for its California smog inspection.

What is OBD II monitor readiness?

On 1996 and newer model year vehicles, the on board diagnostic system (OBDII) performs up to eleven diagnostic checks of vehicle emission control systems.  These checks are performed in the background during normal driving and are designed not to interfere with vehicle performance or safety.

If a fault is detected, the power train control module (PCM – The computer) illuminates the malfunction indicator light (MIL – Check Engine – Service Vehicle Soon).

If the PCM loses power for any reason (Including a disconnected or depleted battery), or if diagnostic trouble codes are cleared using a diagnostic scan tool, readiness monitors will indicate an incomplete, or not ready, status.

In most cases, a vehicle with incomplete readiness monitors will not pass the California smog inspection (See New Readiness Monitor Standards For OBD II Functional Inspection).

Driving the vehicle under conditions that meet the monitor enabling criteria should complete most OBD II monitors.  This is usually accomplished after fifty to one-hundred miles of normal driving.

How to check monitors without a scan tool

In most cases, the correct procedure is outlined in your vehicle’s owner’s manual. Consult your owner’s manual for information specific to the car you drive.

However, the following procedures are presented as examples. They may not apply to your specific vehicle.

Ford/Lincoln/Mercury Vehicles

To determine if readiness OBD II monitors are complete:

  1. Turn the ignition key to the “on” position for 15 seconds without cranking the engine.
  2. If the “Service Engine Soon” light blinks eight times, one or more readiness monitors are incomplete.
  3. If the service engine soon indicator stays on solid, all readiness monitors are complete.

This procedure was included in the Owner’s Manual for a 2012 Ford Focus. This same procedure may apply to other models and model year Ford/Lincoln/Mercury vehicles.

For Jeep, Chrysler and Dodge

The owner’s manual states that the vehicle has a simple ignition key actuated test, which you can use prior to going to the test station. To check if your vehicle’s OBD II system is ready, you must do the following:

  1. Turn the ignition switch to the “ON” position, but do not crank or start the engine. If you crank or start the engine, you will have to start this test over.
  2. As soon as you turn the ignition switch to the ON position, you will see the MIL (Check Engine Light) symbol come on as part of a normal bulb check.
  3. Approximately 15 seconds later, one of two things will happen:
    1. The MIL will flash for about 10 seconds and then return to being fully illuminated until you turn OFF the ignition or start the engine. This means that your vehicle’s OBD II system is not ready and you should not proceed to the smog check station.
    2. The MIL will not flash at all and will remain fully illuminated until you turn OFF the ignition or start the engine. This means that your vehicle’s OBD II system is ready and you can proceed to the smog check station.
Honda/Acura

To check if the readiness codes are set, turn the ignition switch to the ON (II) position, without starting the engine. The MIL will come on for 20 seconds. If it then goes off, the readiness monitors are set. If it blinks five times, the readiness monitors are not set.

14 Replies to “Check OBD II Monitor Readiness Without A Scan Tool”

    • Marion Caffroy

      It seems to me that the method for all vehicle manufacturers is going to be the same;put the key in the ignition, turn it to the on position without starting the car,&just wait anywhere from 10-30secs & watch what it does. From there just do a simple Google search describing what it did making sure to include the word “Nissan” in the search as well.. I could be wrong I really don’t know im just using a bit of context clues&deductive reasoning. Regardless, I don’t think it could hurt to try,right? Good luck!

      Reply
    • dewok

      Hi Richard,

      When you say OBD2 Light, I’m assuming you mean the check engine light (MIL). You can push the start button without depressing the brake pedal. The MIL should illuminated. Once started the MIL should go away.

      Reply
    • dewok

      Assuming that you are driving in the correct conditions to complete monitors and the monitors are still not setting, it is possible that there is something else wrong. For example, for many vehicles, if the thermostat is stuck open, the catalyst monitor will never complete.

      Reply
  1. Glen

    What years do these procedures work with? My 2000 Dodge does not seem to comply. ALSO, the clearing of DTC’s does NOT reset the readiness monitors unless OBDII regulations have changed. I have cleared codes on a number of vehicles dating 2011 and older without resetting the readiness monitors. The pain in the butt readiness test that is hardest to complete is one that requires more than 1 drive cycle (turn on, drive, turn off), that also requires minimum speed over 50mph and a minimum cold start temp of 38 degrees F or something close to that.

    Reply
    • dewok

      Hi Glen,

      I cannot recall a time when we have cleared a DTC and the readiness monitors do not reset. On most vehicles (operation properly) 3 monitors will set to ready upon initial startup post clearing: MIS, FUE & CCM.

      Ninety percent of the drive cycles we complete (on properly operating vehicles) are completed without following overly specific drive cycle instructions.

      On the vehicles we service that require monitor completion, 50% of the time the vehicle needs a repair and the other half of the time, the vehicle requires an ultra specific drive cycle / weather conditions. Some vehicles are just stubborn.

      Sorry we couldn’t provide more help.

      Danny
      JUST SMOGS

      Reply
  2. Kat

    What about a Mazda RX-8, which has a rotary engine? Do any of the above-mentioned steps apply, and if so, which ones? It’s an interesting catch-22 in that I’m required to drive 50 to 100 miles to reset the OBDII while bearing expired tags, because: no smog pass, no reg tags; no reset, no smog. I’m in L.A. and most cops don’t play. Just have to hope I don’t get pulled over and if I do, it’s by a decent cop who will understand what I’m doing and not shake me down. Thanks..

    Reply
    • dewok

      Hi Kat,

      I would follow the Toyota Drive cycle.

      I can’t recall ever having trouble with Mazda RX-8 readiness monitors. Many of our LA based customers are unable to complete the catalyst monitor because they are unable to drive at a steady 55mph for an extended period of time due to Los Angeles traffic. With that said, we’ve had multiple customers complete the catalyst monitor on the way down to Huntington Beach to visit us for our drive cycle / diagnostic service.

      Lastly, I recommend going to AAA or the DMV and getting a moving permit. This will allow you to drive the vehicle legally during this process.

      Good luck!

      Reply
      • Scott

        All of the above tests to determine if your car is ready for its emissions basically are saying the same thing regardless what type car you have. Just turn the key to rhe on position (without cranking rhe car) and watch your check engine light for rhe next 15-20 seconds. If it blinks multiple times then your car is NOT ready for emissions testing, but it the light stays on without blinking or it simply disappears then your sensors are ready so you can proceed to getting your emissions test done. They are needlessly confusing matters by listing makes & models of cars as the steps of all the above are basically saying the same thing…

        Reply
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