Confusion About OBD II Monitors

I’ve written more about OBD II readiness monitors than any other subject that I’ve covered at JustSmogs.com. Unfortunately, I don’t think that I’ve done a very good job explaining what they are.

…If the monitor on my car is the problem, how much does it usually cost to get a replacement monitor?

Comment from a reader in response to:
Smog Check OBD II (OBD 2): What are Readiness Monitors?

Is an OBD II monitor bigger than a breadbox?

An OBD II readiness monitor is not something that you can see, touch, smell or taste. You can not repair or replace an OBD II readiness monitor.

If you were told that your vehicle did not pass a smog inspection because your car’s OBD II readiness monitors were not complete, it doesn’t mean that you have a bad monitor.

OBD II readiness monitors are not sensors!

Your car has an engine control module (Computer).  That computer is loaded with software that performs many functions.  Some of those functions, or processes, are referred to as OBD II readiness monitors.

OBD II readiness monitors are software processes that monitor (Test) critical emissions control systems.

These processes (Monitors) are referred to by name of the system(s) that they monitor (Test).

Just Smogs® 7722 Talbert Ave, Huntington Beach, CA

Fuel Management

Misfire

Comprehensive Component (Shorts, opens, other electrical issues)

Catalyst

Heated Catalyst (Uncommon)

O2 Sensor

O2 Sensor Heater

Evap

Secondary Air Injection

EGR/VVT

Not all of the above monitors will be programmed into every vehicle.  For example, there will be no Secondary Air Injection monitor on a vehicle that is not equipped with a secondary air injection system because there is no secondary air injection system to monitor (test) on that vehicle.

Again, OBD II readiness monitors are tests run by your vehicle’s computer software. OBD II readiness monitors are not physical components or sensors.

…So if you have a ford or chevy with 9 monitors, 8 have to be ready if you have a brand new german car with 100 sensors, 99 have to be ready – how stupid is that….. “1 not ready” is a stupid criteria. My old ’95 only had 2 sensors – so “none” ready would have passed…

Excerpt from a forum post at
http://www.g6ownersclub.com

The author of that post is a confused about OBD II monitors, but that’s OK, so are many automotive professionals.

Also, there is not a 1:1 ratio between monitors and sensors. Even if a gasoline powered vehicle is equipped with “100 sensors”, It will have no more OBD II readiness monitors than those listed above.

Why are OBD II Readiness Monitors Important?

When your car’s computer detects a problem that could cause an increase in harmful emissions (Smog), it will set a diagnostic trouble code (DTC) and turn on the “Check Engine Light”.

The check engine light is also known as the Malfunction Indicator Light (MIL), Service Engine Soon, and the funny looking thing with the lightning bolt going through it).

The computer identifies problems by running the diagnostic tests that we call monitors.

If no diagnostic trouble codes are stored in memory and all OBD II readiness monitors are complete, it is safe to assume that the vehicle’s emissions control systems are working properly; however, if the monitors are incomplete, there might be a problem with the emissions control system that has not been identified.

Since OBD II testing and system health is a major component of today’s smog inspection, a vehicle can not pass a smog inspection unless all systems are ready.

If they’re not broke, then why aren’t my monitors ready?

By design, OBD II monitors are composed by tests that run in the background and the average motorists never has to give OBD readiness monitors a second thought.

OBD readiness monitors are normally “Ready” (Complete). If OBD II monitors are “Not Ready” (Incomplete), it is usually because of one of the following reasons:

The computer lost power

The results of tests run by OBD II readiness monitors are stored in what is known as volatile memory.

Volatile memory, contrary to non-volatile memory, is computer memory that requires power to maintain the stored information; it retains its contents while powered on but when the power is interrupted, the stored data is lost immediately or very rapidly.

wikepedia.org

That means that if the computer in your vehicle looses power for any reason, the results of tests run by the computer’s OBD II readiness monitors will be cleared (erased, deleted, etc).

Reasons for a vehicle’s computer to loose power commonly include:

  • A dead or depleted battery.
  • A battery that has been disconnected.
  • Electrical problems that could include blown fuses and damaged wiring.

One of my customers had an ignition interlock device installed on her vehicle after she plead guilty to a DUI. The device installed on her vehicle worked by interrupting the power supply to her car’s computer.

Because of that interlock device, the OBD II readiness monitors on her car were cleared every time she turned switched off the ignition on her car.

When power returns to the computer all monitors will indicate a “Not Ready” or “Incomplete” state (The term used will depend on the diagnostic scan tool used to check monitors).

Cleared with a diagnostic scan tool

When a car comes into a shop with an illuminated check engine light (MIL), the vehicle should be properly diagnosed and repaired.

In some cases the check engine light may be cleared as part of the diagnostic process.  A technician might gather relevant information, and then verify that the problem still exists by clearing the code and confirming that the code returns under similar conditions.

In any case, the check engine light is usually cleared following the completion of repairs.

By design, when codes are cleared using a diagnostic scan tool or code reader, OBD readiness monitors are also cleared.

Most shops will instruct their customer to drive the car normally, and return to the shop only if the original symptoms, including the illuminated check engine light, return. In most cases this isn’t a problem, but what if the customer leaves the repair shop and drives straight to a smog shop? That customer might have a problem.

So, what do I have to do to get my monitors ready?

Drive your car!

I won’t begin to describe some of the silly and outright dangerous schemes that people come up with to avoid driving their own cars.

Each monitor (Test) has a specific set of conditions (Enabling criteria) that must be met before that monitor can be run to completion.

The best way to complete readiness monitors, especially on car that is having trouble completing those monitors, is to obtain a copy of the manufacturer’s suggested drive cycle. In most cases, that drive cycle is only an internet search away.

I can’t do that in Los Angeles/Orange County traffic!

At Just Smogs® in Huntington Beach, we frequently perform OBD II readiness drive cycles for our customers during normal business hours.

Earlier this month, a customer from Temecula  brought us a Jeep with “impossible to run monitors”.  After allowing the Jeep to fully cool down, one of my team members warmed up the Jeep and took it out for a spin. He was back in less than an hour. All monitors were complete.

Here are some tips for running monitors and difficult vehicles:

  1. Follow all manufacturer instructions, not just the ones you like.  Deviating from the drive cycle instructions briefly can take you back to square one.
  2. I often recommend running monitors early on a Saturday or Sunday morning when traffic is usually light. Also, some monitors will not complete during extremely hot or cold weather (Usually the EVAP monitor).
  3. In most cases, allow the vehicle to cool down completely overnight. It’s usually important to perform a complete warm up cycle before beginning the drive cycle.  Allow the vehicle to warm up naturally while idling. Unless the drive cycle instructions indicate otherwise, avoid revving the engine in an effort to warm it up quickly.
  4. Once again, follow the manufacturer’s instructions completely!

I’ve done all that, and they still wont run!

There are times when the drive cycle will not work!

Normally a problem with a monitored system, sensor,  or other component, will trigger a diagnostic trouble code and the computer will turn on the check engine light.

However, sometimes an under-performing system that is on the verge of failure will prevent the completion of a test, but not trigger a diagnostic trouble code.

For example an under-performing oxygen sensor might prevent the completion of a catalyst monitor, or an exhaust leak might affect an oxygen sensor’s performance just enough that it prevents the monitor from running to completion. Even though the check engine light might be off, a monitor might not complete until necessary repairs are performed.

Some vehicles have known software or hardware issues that prevent monitors from being run to completion. In those cases the vehicles computer may require reprogramming or  replacement.  The vehicle may even be subject to a manufacturer recall.

More information about OBD II monitors and problem vehicles can be found in the OBD II Smog Check OBD Reference maintained by the California Bureau of Automotive Repair.

Just Smogs® in Huntington Beach specializes in the diagnosis and repair of emissions related issues including OBD II monitor issues.  For information about diagnostics, repair, or the Just Smogs® monitor drive cycle service, call Just Smogs® at (714) 596-1019.

 

Volkswagen OBD II Monitor Drive Cycle

A reader wrote in to say that she’s having trouble getting her 2007 Volkswagen Rabbit to complete OBD II monitors.  I shared the following drive cycle wither her, and decided to post it here for others experiencing similar issues with their Volkswagen vehicles.

This drive cycle should be valid for Volkswagen engine codes BGP and BGQ.

  • Switch the ignition on and start the vehicle.
  • Idle the vehicle for 2-3 minutes. This executes the O2S Heater, Misfire, Secondary AIR, Fuel Trim, and Purge system monitors.
  • Drive the vehicle at 45-55 mph for a continuous 7 minute period, avoid stopping. This executes the EVAP, O2S, Fuel Trim, and Misfire monitors.
  • Accelerate the vehicle to an engine speed of 5000 RPM (with automatic transmission use the tip-tronic mode) lift off the throttle until the engine speed is around 1200 rpm. This executes the fuel cut off
  • Accelerate the vehicle smoothly to 60-65 mph, cruise constantly for 5 min, this executes the Catalyst, O2S, Misfire, Fuel Trim, and Purge System monitors.
  • Decelerate and idle the vehicle again for 3 minutes. This executes the Misfire, Secondary AIR, Fuel Trim, and Purge system monitors.

As with most OBD II monitor drive cycles, a complete warm-up cycle is recommended. In other words, let the vehicle cool down completely and allow the vehicle to warm up to full operating temperature from a cold start before commencing the drive cycle. Also, it might be necessary to perform the drive cycle on a weekend morning when traffic is light.

Drive safely and observe all traffic laws while performing the drive cycle. Several attempts may be required. Rinse and repeat as necessary.

January 2017 California Smog Check FAQ

Smog Check Frequently Asked Questions for January 2017

How many readiness monitors have to be complete to pass smog?

What if I cannot get my smog test in California before it is due?

Can I go to another smog check station after failing?

The shop that failed my car also does repairs, can I go someplace else for repairs?

A relative gave me a car, do I need a smog inspection?

If my check engine light doesn’t turn on at all will I pass smog?

If you fail OBD II on a smog check, should your overall smog fail?

Where can I get a STAR Smog Inspection in Huntington Beach?

How many readiness monitors have to be complete to pass smog?

check engine lightThis continues to be number one on the hit parade.  Nobody wants to hear the dreaded words, OBD II not ready.

1996 to 1999 Gasoline powered vehicles: Any one monitor can be incomplete.

2000 and newer Gasoline powered vehicles: All monitors, with the exception of the EVAP monitor must be complete.

1998 to 2006 OBD II certified diesel powered vehicles: All monitors must be complete.

2007 and newer OBD II certified diesel powered vehicles: Any two monitors can be incomplete.

For more information about OBD II Monitors:

OBD II, “CHECK-ENGINE” LIGHTS, and READINESS MONITORS..WHAT ARE THEY?

OBD Monitors and Testability Issues

What if I cannot get my smog test in California before it is due?

 

Pay your fees!

Even if you do not pass smog, you can avoid paying late fees by paying all registration fees on time.  While the DMV will not issue a registration renewal until all requirements, including the smog certification, are complete, the DMV will stop assessing further late fees upon receipt of your payment.

You may also be eligible for a temporary moving permit.  Contact the California DMV for more information.

Can I go to another smog station after failing?


Absolutely! Many people are under the mistaken impression that they have to return to the original smog shop to finish the smog inspection after failing. Not true.  Pass or fail, that smog inspection ended when you received the results. It’s done. You are free to have the vehicle inspected at any shop.

Of course, if the vehicle requires an inspection at a STAR certified shop, you must take it to a STAR station.

Also, it important to note that if the shop that inspected your vehicle promised you a free retest, or any other discounts, those promises only apply at the shop that made the offer

The shop that failed my car also does repairs, can I go someplace else for repairs?

Again, absolutely.  Shops performing emissions repairs in the State of California are required to be licensed by the Bureau of Automotive Repairs; however, you are not obligated to have your vehicle repaired by the shop that performed the smog inspection.

A relative gave me a car, do I need a smog inspection?

 

If you acquire a vehicle that is currently registered in California from a spouse, domestic partner, sibling, child, parent, grandparent, or grandchild, you are entitled to an exemption from the smog inspection. Other family members or relations are not exempt and are required to obtain a smog inspection certification.

For more information read “Transfer a Vehicle Between Family Members.

www.dmv.ca.gov

If my car check engine light doesn’t turn on at all will I pass smog?

No, if the check engine light (Service Engine Soon, MIL, etc), is burned out, missing, disconnected, or not functioning normally for any reason, the vehicle will not pass the California smog inspection.

If you fail OBD II on a smog check, should your overall smog fail?

If a vehicle fails any part of a smog inspection the state’s software will not certify the vehicle. In other words, the vehicle will fail.

As a matter of fact, if the check engine light isn’t on, the technician inspecting your car won’t know your car failed until the test is over.

Where can I get a STAR smog inspection in Huntington Beach?

Huntington Beach, Newport Beach, Fountain Valley, and beyond, the choice is simple!  For any and all smog inspections, booking an appointment at Just Smogs® in Huntington Beach will be the best smog inspection decision you’ll ever make.

Click here, or call (714) 596-1019 to make an appointment.

2003 Chrysler PT Cruiser

Some 2003 Chrysler PT Cruisers (2.4 liter DOHC 16v turbocharged, sales code EDV, with 5- spd manual G288 trans, sales code DDD) are unable to complete the OBD II Catalyst monitor because of a firmware error.

Chrysler is aware of the problem, and a firmware update is required to correct the problem.

If you own an affected vehicle, please contact your Chrysler dealer for more information.  Reference technical service bulletin number 18-112-16.  Repair reimbursement may also be available.  Per waranty D-16-26, the warranty for reprogramming the PCM on affected vehicle has been extended to a lifetime warranty.

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?

smog-check-lamborginijpg

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.

 

O2 Sensor Monitor Not Ready 2007 Toyota Highlander Hybrid

2008_09_09highlander_hy_33-prvIf your 2007 Toyota Highlander Hybrid fails to pass the California emissions test because of an incomplete oxygen sensor (air/fuel) monitor, your Toyota Highlander Hybrid may be subject to a recall.

Affected vehicles will require a software update to correct an issue that prevents the vehicle’s on board diagnostic computer from running the O2 sensor monitor to completion.  Per Toyota Special Service Campaign FOP and TSB #0042-15, this service will be performed on affected vehicles at no charge to the consumer.

Your Toyota dealer will identify affected vehicles based on manufacture date, software calibration, etc.  When contacting your Toyota dealer, please reference TSB #0042-15.

BAR OIS Testing And Invalid Monitor Information

On August 1, 20016, the Bureau of Automotive Repair (BAR) implemented a change in the BAR-OIS testing procedure that may result in a new type of smog inspection failure.

What is BAR-OIS testing?

just-smog-check-huntington-beach-3-bays-800x480The BAR-OIS is the Smog Check equipment required when inspecting most model-year 2000 and newer gasoline and hybrid vehicles and most 1998 and newer diesel vehicles. The system consists of a certified Data Acquisition Device (DAD) and off the shelf equipment, including a computer, bar code scanner, and printer.

During a BAR-OIS smog inspection, the DAD collects data from your vehicle’s Power train Control Module (PCM), or as most people call it, “The Computer”.

The data collected by the DAD includes diagnostic trouble code information (Mode $03), Vehicle Information (Mode $09), and the current monitor information from Mode $01. Other data is also collected, but for the purpose of this article, we’ll focus on Mode $01 monitor information.

OBD II Monitor Readiness

Image of instrument cluster including "Check Engine" lightOBD II Monitor Readiness is a key element of the BAR-OIS smog inspection process.

Most model year 2000 and newer gasoline powered and hybrid vehicles can pass the BAR-OIS inspection if EVAP is the only incomplete monitor; otherwise, all other OBD II monitors must be complete.

While most vehicles behave as expected, some vehicles do not respond with proper OBD monitor information from the PCM, or the transmission computer responds instead of the engine computer.

In most cases cycling the vehicle’s ignition (off/on) will solve the problem, but occasionally the vehicle will continue to respond with invalid or no data.

Prior to August 1, 2016, a vehicle could pass the BAR-OIS inspection if this condition continued; however, that is no longer the case.

What has changed?

toyota-drive-cycle-obd-readiness-monitor-smog-checkEffective August 1, 2016, if a vehicle continues to respond with improper OBD II monitor information, the vehicle will fail the inspection.

If a vehicle in the following list fails for invalid OBD II monitor information, it should be referred to the BAR Referee. Vehicles not included in the list will most likely require repairs.

  • 2004 Volvo C70 HPT
  • 2004 Volvo C70 LPT
  • 2004 Porsche Boxster S
  • 2004 Porsche Boxster
  • 2003 Porsche Boxster

 

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.

Smog Check OBD Reference Update

The Bureau of Automotive Repair has issued an update to the Smog Check OBD Reference Guide.  The update check engine lightincludes new service bulletins, emissions recalls and information on the following vehicles:

  1. BMW 323i: ECM reflash recall is needed to set oxygen sensor monitor.
  2. 2000-2001 Nissan Maxima and Infinity I30:  New catalyst may be needed to run catalyst monitor.
  3. 2001 Chevrolet Silverado and Tahoe C/K 1500: Send to BAR Referee only if secondary air monitor is not running.
  4. 2002 Chevrolet Silverado C/K 2500 HD Diesel: Send to BAR Referee only if EGR monitor is not running.
  5. 2009 Kia Borrego LX/EX: Send to BAR Referee only if EGR monitor is not running.
  6. 1999-2006 Nissan UD1200 Box Truck (10-14K GVWR, Federal Diesel): Not equipped with OBD, BAR-OIS skips OBD test.
  7. 2003 Chrysler PT Cruiser 2.4 liter turbo: Catalyst monitor not running.  BAR-OIS allows any one monitor.
  8. 2001-2002 Chevrolet Cavalier CNG: Catalyst monitor not running.  BAR-OIS allows any one monitor to be incomplete.

Click here to view the complete Smog Check OBD Reference Guide.

OBD Monitors and Testability Issues

OBD Monitor Readiness

check engine lightReadiness monitors are self- tests performed by a vehicle’s on board diagnostic (OBD) system to verify emission control functionality.

While most vehicles complete the various self tests during normal driving, achieving monitor readiness in a few types of vehicles is more difficult due to the vehicle design requiring unusual operating conditions or due to the fact that the owner never drives the car in the necessary operating mode.

Monitor completion is also dependent on properly functioning components, so a vehicle may never complete a monitor until a thorough diagnosis and repair of affected components is performed.

Readiness monitors must be rerun after a repair activity like disconnecting a vehicle’s battery, clearing diagnostic trouble codes,  or replacing a defective emissions component.

OBD Test Monitor Readiness Standards
(Implemented May 4, 2015)
Model Years Fuel Type total Incomplete Monitors allowed
1996-1999 Gas* Any One
2000 and newer Gas* Evaporative system
1998-2006 Diesel Zero
2007 and newer Diesel Any two
*”Gas” includes gasoline, propane, natural gas (CNG, LNG, LPG)

OBD Monitor Readiness Testability Issues

Some vehicle models are known to have issues that interfere with the successful completion of OBD readiness monitors.  The State of California Bureau of automotive repair maintains a list of these vehicles and specific remedies, if known, that can assist a motorist in completing monitors.  In some cases repairs may be required, and in others test equipment is programmed to ignore some or all readiness monitors on affected vehicles.

To learn more about OBD readiness monitors and testability issues, please download the Smog Check OBD Reference from the Bureau of Automotive Repair website.