OBD II Monitor Drive Cycle Service

multiple-smog-check-fountain-valleyIn recent years the California Bureau of Automotive Repairs (BAR) and the California Air Resource Board (CARB) have increasingly shifted the emphasis of the California emissions program to on-board diagnostic trouble codes &  monitor readiness. This is especially true for 2000 and newer model year vehicles.

If you are having trouble completing OBD II readiness monitors on your 1996 or newer vehicle, the licensed professionals at Just Smogs® in Huntington Beach can help.

OBD II Monitor Recap

What are OBD II readiness monitors?

just-smog-check-fountain-valley-front-800x480The short answer is that OBD II readiness monitors are usually something that average motorists never have to worry about until they have a reason to worry.

OBD II readiness monitors are self tests run by a vehicle’s on board diagnostic system.  OBD II monitors have two states: ‘ready’ and ‘not ready’.  Some scanners and code readers may display ‘complete’ , ‘incomplete’ , comp, inc, etc.  It all comes down to whether or not a test has been run to completion.

When one of these test fails, the check engine light is illuminated; otherwise, a driver normally has no indication that OBD II readiness monitors exist.

So what’s the problem?


It’s not uncommon for OBD II readiness monitors to be reset following repairs.  This is especially true if the check engine light was on.

If a vehicle’s power train control module (PCM – ‘The Computer’) loses power due to a dead or depleted battery, or if diagnostic trouble codes are cleared using a scan tool, all readiness monitors are automatically set to incomplete/not ready.

Incomplete readiness monitors aren’t  something that you have to worry about unless your vehicle is due for a smog inspection.

Readiness monitors are run in the background and by design do not affect driveability, safety, or fuel economy, but they are an important part of the California smog inspection program.

In order for a vehicle to pass a smog inspection in the state of California, most OBD 2 monitors must be run to completion.  For example, in order for most 2000 and newer gasoline powered vehicles to pass the smog inspection all monitors with the exception of the evap monitor must be complete.  If any monitor other than the evap monitor is incomplete the vehicle will fail the smog inspection.

If you’ve ever had an issue with OBD II readiness monitors, you’ve probably heard the phrase, “Drive it fifty to one-hundred miles and you should be fine”.

I drove my car hundreds of miles, and it still isn’t ready!

Some cars are known to have issues that can make completing OBD II readiness monitors extremely difficult.star-smog-check-technician-licensed-800x480

BAR maintains a list of such vehicles and possible solutions (The Smog Check OBD II Reference).

Very often the solution involves following a very specific drive pattern that some motorists find difficult to complete during their normal driving routine.  That’s when Just Smogs® can help.

Just Smogs® OBD II Drive Cycle Service

huntington-beach-smog-store-frontIf your vehicle is otherwise in good repair, and you are having difficulties completing the OBD II drive cycle, the professionals at Just Smogs® can complete the drive cycle on most vehicles that do not require further repair or diagnosis.

This service offering does not include any diagnostics or repairs that may be necessary to enable the OBD II drive cycle, nor does it include diagnostics or repairs that may become necessary should the drive cycle trigger a diagnostic trouble code or check engine light.

Of course in most cases you should be able to complete the drive cycle yourself with no more effort than a Sunday drive, but in case you can’t, the professionals at Just Smogs® are here to help.

For more information about Just Smogs® OBD II drive cycle service, call (714) 596-1019.


1996 to 2002 Toyota OBD II Catalyst Monitor Readiness Drive Patterns

The catalyst monitor on many Toyota vehicles can be difficult to complete.  That’s why it’s important to follow the Toyota recommended drive cycle after performing actions that are known to clear your Toyota’s computer memory.

Remember, all on-board diagnostic monitors are cleared when the battery is disconnected, or when the power train control module (PCM) is cleared with a scan tool.


  1. Do not turn off the ignition switch during the test procedure.
  2. Allow the vehicle to run at idle until warmed up.
  3. Drive at a steady speed between 40 and 70 MPH for 10 minutes.  It’s a good idea to stay in the middle of this range, so 55 MPH is optimal.
  4. It may take several attempts and warm up cycles to complete the drive cycle.





1996 to 2002 Toyota OBD II Monitor Readiness Drive Patterns

Smog Check OBD II (OBD 2) : What are Readiness Monitors ?


OBD II is a system that has been installed in most 1996 and later cars and light trucks, intended to inform the driver of problems in the components that control the engine and transmission. The primary reason OBD II was invented is to reduce smog emissions caused by malfunctions, but it is also valuable as an alert to the driver that something is wrong…something that can affect gas mileage and drivability, or actually cause further damage to the vehicle.

Continue Reading →

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. Continue Reading →