**DMV Smog Requirements OBD2: Your Complete Guide to Compliance**

Navigating the DMV smog check requirements with your OBD2 system can be straightforward with the right information. OBD2-SCANNER.EDU.VN is here to help you understand the smog check process, potential issues, and how to ensure your vehicle passes the test smoothly, leveraging our expert insights and diagnostic solutions. By understanding the nuances of onboard diagnostic systems and emission standards, you can avoid unnecessary repairs and ensure your vehicle meets all requirements.

1. What are DMV Smog Requirements OBD2?

Dmv Smog Requirements Obd2 (On-Board Diagnostics II) refer to the standards vehicles must meet during a smog check, focusing on the OBD2 system’s data. The OBD2 system monitors your car’s emissions and overall health, reporting any issues through diagnostic trouble codes (DTCs). According to the California DMV, vehicles manufactured from 1996 onwards are generally subject to OBD2-based smog checks. These checks verify that your car’s computer system is functioning correctly and that all emission control systems are operating as intended, playing a crucial role in maintaining air quality and environmental standards. Understanding these requirements helps car owners ensure compliance, avoid penalties, and contribute to cleaner air.

What is an OBD2 System?

An OBD2 system is an onboard diagnostic system in vehicles that monitors engine performance, emissions, and other critical functions. According to the EPA, OBD2 systems were standardized in 1996 for all cars sold in the United States. The system uses sensors to detect malfunctions, stores diagnostic trouble codes (DTCs), and illuminates the malfunction indicator lamp (MIL), commonly known as the “check engine light.” This standardized system allows technicians and vehicle owners to identify and address issues quickly, ensuring vehicles operate efficiently and within emission standards.

Why are OBD2 Smog Checks Required?

OBD2 smog checks are required to ensure vehicles comply with state and federal emission standards, reducing air pollution and promoting environmental health. By monitoring the performance of emission control systems, OBD2 checks help identify vehicles that exceed allowable pollution levels. The California Air Resources Board (CARB) emphasizes that regular smog checks are crucial for identifying and repairing high-emitting vehicles. This proactive approach helps maintain cleaner air and protect public health by minimizing harmful pollutants released into the atmosphere.

Which Vehicles Require OBD2 Smog Checks?

Vehicles manufactured from 1996 onwards are generally subject to OBD2 smog checks, as mandated by the Environmental Protection Agency (EPA). However, specific state regulations, such as those in California, may have additional requirements or exemptions. For example, some hybrid and electric vehicles might have different testing protocols, and older vehicles may be subject to alternative inspection methods. Always verify the specific requirements of your state’s DMV or environmental protection agency to ensure compliance.

2. Key Components of a DMV Smog Check OBD2

A DMV smog check using OBD2 involves several critical tests to ensure your vehicle complies with emission standards. According to the Bureau of Automotive Repair (BAR), these tests primarily focus on three key areas: readiness monitors, the malfunction indicator lamp (MIL), and communication standards. Understanding each component can help you prepare your vehicle and ensure it passes the inspection smoothly.

Readiness Monitors: What Are They?

Readiness monitors are self-tests performed by your vehicle’s OBD2 system to verify the functionality of emission control components. These monitors confirm that systems like the catalytic converter, oxygen sensors, and evaporative emissions control are working correctly. The California DMV specifies that vehicles must have all applicable monitors in a “ready” state to pass the smog check. Understanding and ensuring your vehicle’s readiness monitors are complete can prevent unexpected failures during the inspection.

How Many Incomplete Monitors Are Allowed?

The number of incomplete OBD readiness monitors allowed to pass the OBD test portion of a Smog Check inspection are provided below.

Model Year	Fuel Type	Number of Incomplete Monitors Allowed to Pass OBD Test1
1996-1999	Gas2	Any one3
2000 and newer	Gas2	Evaporative system3
1998-2006	Diesel	Zero
2007 and newer	Diesel	Particulate Filter and Non-Methane HydroCarbon (NMHC)4

1 Implemented May 4, 2015.

2 “Gas” includes gasoline, propane, natural gas (CNG, LNG, LPG).

3 The misfire, fuel, and comprehensive component continuous monitors are ignored during an OBD test on “gas” vehicles.

4 Implemented July 5, 2023.

Why Are Readiness Monitors Important?

Readiness monitors are crucial because they confirm that your vehicle’s emission control systems are functioning correctly, reducing harmful pollutants. The EPA emphasizes that readiness monitors ensure vehicles meet emission standards, contributing to cleaner air. Completing these monitors is essential for passing a smog check and demonstrating your vehicle’s commitment to environmental responsibility.

How to Complete Readiness Monitors

Completing readiness monitors often requires a specific drive cycle, which involves driving your vehicle under certain conditions to allow the OBD2 system to run its self-tests. According to the California DMV, these conditions may include specific speeds, durations, and temperature ranges. Consult your vehicle’s owner’s manual or a trusted mechanic at OBD2-SCANNER.EDU.VN for the exact drive cycle needed for your car model. Performing the correct drive cycle can help ensure all readiness monitors are set, increasing your chances of passing the smog check.

Malfunction Indicator Lamp (MIL): What Does It Indicate?

The Malfunction Indicator Lamp (MIL), often called the “check engine light,” illuminates when the OBD2 system detects an issue that could affect emissions. According to the EPA, the MIL indicates that a diagnostic trouble code (DTC) has been stored in the vehicle’s computer. Addressing the cause of the MIL illumination is crucial for passing a smog check and maintaining your vehicle’s optimal performance.

A lit check engine light indicates potential issues picked up by the OBD2 system, requiring attention before a smog check.

MIL Standards for Passing/Failing

The Malfunction Indicator Lamp (MIL or “Check Engine” light) related failure standards for the OBD test portion of a BAR-97 and OIS inspection are provided below.

Vehicle	Pass/Fail	Standard
All with OBDII	Pass	MIL illuminates when key on engine off (KOEO).
All with OBDII	Pass	MIL turns off when engine running (KOER).
All with OBDII	Fail	MIL does not illuminate when key on engine off (KOEO).
All with OBDII	Fail	MIL illuminates when engine running (KOER).

Common Reasons for MIL Illumination

Several common issues can trigger the MIL, including a loose gas cap, faulty oxygen sensors, a failing catalytic converter, or problems with the spark plugs. A study by the National Institute for Automotive Service Excellence (ASE) found that oxygen sensor failures and catalytic converter issues are among the most frequent causes of MIL illumination. Identifying and addressing these common problems promptly can help prevent more significant damage and ensure your vehicle passes the smog check.

How to Address MIL Issues

To address MIL issues, start by using an OBD2 scanner to retrieve the diagnostic trouble code (DTC). This code will provide insight into the specific problem triggering the light. The California Bureau of Automotive Repair (BAR) recommends consulting a certified mechanic for accurate diagnosis and repair. Depending on the issue, you may need to replace a faulty sensor, repair an exhaust leak, or address other underlying problems. Addressing these issues promptly ensures your vehicle meets emission standards and avoids smog check failures.

Communication Standards: Ensuring Proper Connection

Communication standards ensure that the OBD2 scanner can properly connect to your vehicle’s computer and retrieve the necessary data. A vehicle may fail for no communication for a variety of reasons including, but not limited to, a damaged OBD connector or wiring, an aftermarket stereo, a transmission computer response instead of engine computer response, and invalid data from the vehicle. The California DMV requires that the OBD2 system communicates effectively with the testing equipment.

Why is Communication Important?

Proper communication between the OBD2 scanner and your vehicle’s computer is essential for accurate smog check results. Without a stable connection, the testing equipment cannot retrieve the necessary data to assess your vehicle’s emissions performance. The Society of Automotive Engineers (SAE) emphasizes that reliable communication ensures accurate diagnostic information.

Common Communication Issues

Vehicle communication standards for the OBD test portion of a BAR-97 and OIS inspection are provided below.

Vehicle	BAR-97/OIS	Standard
All with OBDII	BAR-97	Vehicle communicates with BAR-97.
All with OBDII	OIS	Vehicle communicates with OIS and transmits required data.1

1 Required data typically means data from OBD addresses: Mode $01 PID $00, Mode $01 PID $01. Mode $01 PID $00 returns what data is supported on the vehicle. Mode $01 PID $01 returns MIL status, diagnostic trouble codes (DTCs), and monitor status.

Troubleshooting Communication Problems

To troubleshoot communication problems, start by checking the OBD2 connector for damage or corrosion. Ensure the scanner is properly plugged in and powered on. The California Bureau of Automotive Repair (BAR) suggests verifying that your vehicle’s battery has sufficient voltage. If the problem persists, consult a certified mechanic at OBD2-SCANNER.EDU.VN to diagnose and repair any wiring or computer-related issues.

3. Common Reasons for Failing a DMV Smog Check OBD2

Failing a DMV smog check OBD2 can be frustrating, but understanding the common reasons can help you prepare and prevent failures. Key factors often include incomplete readiness monitors, a lit malfunction indicator lamp (MIL), and communication issues between the OBD2 scanner and your vehicle’s computer. Addressing these common problems can improve your chances of passing the test.

Incomplete Readiness Monitors: A Frequent Culprit

Incomplete readiness monitors are a frequent reason for failing a smog check. These monitors, which verify the functionality of emission control systems, must be in a “ready” state for your vehicle to pass. The California DMV specifies that certain monitors must be complete, depending on the vehicle’s model year. Ensuring all required monitors are set before the test is crucial for avoiding failure.

Causes of Incomplete Monitors

Several factors can cause incomplete monitors, including recent battery disconnection, diagnostic trouble code (DTC) clearing, or specific driving conditions that prevent the OBD2 system from running its self-tests. According to the EPA, completing readiness monitors often requires a specific drive cycle. Understanding and addressing these causes can help you prepare your vehicle for the smog check.

Strategies for Completing Monitors Before the Smog Check

To complete monitors before the smog check, perform the appropriate drive cycle for your vehicle, which typically involves driving under specific conditions to allow the OBD2 system to run its self-tests. The California Bureau of Automotive Repair (BAR) recommends consulting your vehicle’s owner’s manual or a trusted mechanic for the correct drive cycle. Avoid clearing DTCs or disconnecting the battery shortly before the test, as this can reset the monitors.

Malfunction Indicator Lamp (MIL) Issues

A lit malfunction indicator lamp (MIL), or “check engine light,” is a common reason for failing a DMV smog check OBD2. The MIL indicates that the OBD2 system has detected an issue that could affect emissions. The California DMV mandates that vehicles with a lit MIL automatically fail the smog check. Addressing the underlying cause of the MIL illumination is essential for passing the test.

Identifying the Cause of MIL Illumination

To identify the cause of MIL illumination, use an OBD2 scanner to retrieve the diagnostic trouble code (DTC). This code will provide insight into the specific problem triggering the light. The National Institute for Automotive Service Excellence (ASE) recommends consulting a certified mechanic for accurate diagnosis and repair. Common causes include a loose gas cap, faulty oxygen sensors, or a failing catalytic converter.

Addressing MIL Issues Before the Smog Check

Addressing MIL issues before the smog check involves diagnosing and repairing the underlying problem indicated by the diagnostic trouble code (DTC). Depending on the issue, you may need to replace a faulty sensor, repair an exhaust leak, or address other mechanical problems. The California Bureau of Automotive Repair (BAR) emphasizes the importance of professional repairs to ensure the issue is resolved correctly. After repairs, clear the DTC and perform a drive cycle to confirm the MIL does not reappear.

OBD2 Communication Problems

OBD2 communication problems, where the scanner cannot properly connect to your vehicle’s computer, can lead to a smog check failure. The California DMV requires that the OBD2 system communicates effectively with the testing equipment. Communication issues can stem from various factors, including a damaged OBD2 port, wiring problems, or computer malfunctions.

Diagnosing Communication Failures

To diagnose communication failures, start by inspecting the OBD2 port for damage or corrosion. Ensure the scanner is properly plugged in and powered on. The Society of Automotive Engineers (SAE) recommends verifying that your vehicle’s battery has sufficient voltage. If the problem persists, consult a certified mechanic at OBD2-SCANNER.EDU.VN to diagnose and repair any wiring or computer-related issues.

Resolving Communication Issues

Resolving communication issues involves addressing the underlying cause preventing the OBD2 scanner from connecting to your vehicle’s computer. Repair or replace a damaged OBD2 port, fix any wiring problems, and ensure your vehicle’s computer is functioning correctly. The California Bureau of Automotive Repair (BAR) advises seeking professional assistance for complex diagnostic and repair work. After addressing the issues, retest the connection to ensure proper communication before the smog check.

4. Step-by-Step Guide to Preparing for a DMV Smog Check OBD2

Preparing for a DMV smog check OBD2 involves several key steps to ensure your vehicle meets all requirements and has the best chance of passing. These steps include performing a pre-smog check, verifying readiness monitors, and addressing any potential issues identified. Following this guide can help you navigate the process smoothly and avoid unexpected failures.

Step 1: Perform a Pre-Smog Check

Performing a pre-smog check can help identify potential issues before the official inspection, increasing your chances of passing. This involves using an OBD2 scanner to check for diagnostic trouble codes (DTCs) and assessing the status of readiness monitors. The California Bureau of Automotive Repair (BAR) recommends this proactive approach for all vehicle owners. A pre-smog check can save you time and money by addressing problems early.

Using an OBD2 scanner for a pre-smog check can identify potential issues early, saving time and money.

Using an OBD2 Scanner for Self-Assessment

Using an OBD2 scanner for self-assessment allows you to retrieve diagnostic trouble codes (DTCs) and check the status of readiness monitors. Plug the scanner into your vehicle’s OBD2 port, typically located under the dashboard, and follow the device’s instructions to read the codes. The EPA recommends familiarizing yourself with your scanner’s manual for accurate readings. Note any DTCs and assess whether readiness monitors are complete.

Interpreting the Results of the Pre-Smog Check

Interpreting the results of the pre-smog check involves understanding the diagnostic trouble codes (DTCs) and readiness monitor status. DTCs indicate specific issues affecting your vehicle’s emissions or performance. The California DMV requires that all applicable readiness monitors be complete. Consult a trusted mechanic or online resources to understand the meaning of any DTCs and the steps needed to complete readiness monitors.

Step 2: Verify Readiness Monitors

Verifying readiness monitors is a crucial step in preparing for a smog check. Readiness monitors are self-tests performed by your vehicle’s OBD2 system to ensure emission control systems are functioning correctly. The California Bureau of Automotive Repair (BAR) specifies the number of incomplete monitors allowed based on the vehicle’s model year. Confirming that all required monitors are complete can prevent unexpected failures during the smog check.

Checking Readiness Monitor Status with an OBD2 Scanner

Checking readiness monitor status with an OBD2 scanner is a straightforward process. After connecting the scanner to your vehicle’s OBD2 port, navigate to the “Readiness Monitor” or “I/M Readiness” section in the scanner’s menu. The scanner will display the status of each monitor, indicating whether it is complete or incomplete. The EPA recommends ensuring all required monitors are complete before proceeding to the smog check.

Completing Incomplete Monitors

To complete incomplete monitors, perform the specific drive cycle recommended for your vehicle. A drive cycle typically involves driving under certain conditions to allow the OBD2 system to run its self-tests. The California DMV suggests consulting your vehicle’s owner’s manual or a trusted mechanic for the correct drive cycle. After performing the drive cycle, recheck the readiness monitor status with the OBD2 scanner to confirm completion.

Step 3: Address Any Issues Identified

Addressing any issues identified during the pre-smog check is essential for ensuring your vehicle passes the official inspection. This involves repairing any problems indicated by diagnostic trouble codes (DTCs), completing incomplete readiness monitors, and addressing any communication issues. The California Bureau of Automotive Repair (BAR) emphasizes the importance of thorough repairs to resolve underlying problems. Addressing these issues proactively can save time and money.

Repairing DTC-Related Problems

Repairing DTC-related problems involves diagnosing and fixing the specific issues indicated by diagnostic trouble codes (DTCs). Consult a certified mechanic at OBD2-SCANNER.EDU.VN for accurate diagnosis and repair recommendations. Depending on the DTC, you may need to replace a faulty sensor, repair an exhaust leak, or address other mechanical issues. After repairs, clear the DTCs with an OBD2 scanner and perform a drive cycle to confirm the issue is resolved.

Ensuring Proper OBD2 Communication

Ensuring proper OBD2 communication involves verifying that the scanner can reliably connect to your vehicle’s computer. Check the OBD2 port for damage or corrosion and ensure the scanner is properly plugged in. The Society of Automotive Engineers (SAE) recommends verifying that your vehicle’s battery has sufficient voltage. If communication issues persist, consult a certified mechanic to diagnose and repair any wiring or computer-related problems.

5. OBD2 Smog Check Requirements by State

OBD2 smog check requirements vary by state, reflecting different emission standards and testing procedures. While the Environmental Protection Agency (EPA) sets federal guidelines, individual states have the authority to implement their own regulations. Understanding the specific requirements of your state is crucial for ensuring compliance and avoiding penalties.

California OBD2 Smog Check Requirements

California has some of the strictest OBD2 smog check requirements in the United States, reflecting the state’s commitment to air quality. The California Bureau of Automotive Repair (BAR) mandates that vehicles manufactured from 1996 onwards undergo regular smog checks. These checks include verifying readiness monitors, ensuring the malfunction indicator lamp (MIL) is not illuminated, and confirming proper OBD2 communication. California also has specific guidelines for vehicles with modified software.

Texas OBD2 Smog Check Requirements

Texas requires OBD2 smog checks in certain counties to ensure vehicles meet emission standards. The Texas Department of Public Safety (DPS) oversees the Vehicle Inspection Program, which includes OBD2 testing for vehicles from 1996 and newer. These tests verify readiness monitors, check for a lit malfunction indicator lamp (MIL), and ensure proper OBD2 communication. Specific requirements and exemptions may vary by county, so it’s essential to check local regulations.

New York OBD2 Smog Check Requirements

New York requires OBD2 smog checks as part of its Vehicle Inspection Program, aimed at reducing air pollution. The New York Department of Motor Vehicles (DMV) mandates that vehicles from 1996 and newer undergo regular inspections, including OBD2 testing. These tests check readiness monitors, the malfunction indicator lamp (MIL), and OBD2 communication. New York also has specific requirements for vehicles registered in certain counties.

6. How OBD2-SCANNER.EDU.VN Can Help You Pass Your Smog Check

OBD2-SCANNER.EDU.VN is dedicated to helping you pass your smog check by providing expert guidance, diagnostic tools, and repair services. Our team of certified mechanics offers comprehensive support to ensure your vehicle meets all OBD2 requirements, from pre-smog check assessments to addressing complex diagnostic trouble codes (DTCs). With our help, you can navigate the smog check process with confidence.

Diagnostic Services

Our diagnostic services include comprehensive assessments of your vehicle’s OBD2 system, helping identify potential issues that could lead to a smog check failure. We use advanced OBD2 scanners to retrieve diagnostic trouble codes (DTCs) and assess the status of readiness monitors. Our certified mechanics at OBD2-SCANNER.EDU.VN provide accurate diagnoses and recommend effective repair solutions.

Certified mechanics at OBD2-SCANNER.EDU.VN use advanced tools for accurate diagnoses and effective repair solutions.

Repair and Maintenance

Our repair and maintenance services address the underlying causes of OBD2-related issues, ensuring your vehicle meets emission standards and passes the smog check. We offer a wide range of services, including replacing faulty sensors, repairing exhaust leaks, and addressing computer-related problems. Our team at OBD2-SCANNER.EDU.VN uses high-quality parts and follows industry best practices to ensure reliable repairs.

Expert Advice and Support

We provide expert advice and support to help you understand OBD2 requirements and prepare for the smog check. Our knowledgeable staff can answer your questions, explain diagnostic trouble codes (DTCs), and guide you through the necessary steps to ensure compliance. Contact us at +1 (641) 206-8880 for personalized assistance and expert insights.

7. Understanding Permanent Diagnostic Trouble Codes (PDTC)

Permanent Diagnostic Trouble Codes (PDTCs) are a specific type of diagnostic trouble code (DTC) that cannot be cleared by simply using a scan tool or disconnecting the vehicle’s battery. The Environmental Protection Agency (EPA) mandates that PDTCs remain until the OBD2 system verifies that the underlying issue has been resolved. Understanding PDTCs is crucial for passing a smog check, as their presence can lead to automatic failure.

What Are PDTCs?

PDTCs are the same as regular diagnostic trouble codes (DTC), but they cannot be erased by clearing the DTCs with a scan tool or by disconnecting the vehicle’s battery. PDTCs can only be cleared by the OBD II system once it has verified that the previously identified defects are no longer present.

Why are PDTCs Important for Smog Checks?

PDTC standards for the OBD test portion of an OIS inspection are provided below.

Model Year	BAR-97/OIS	Standard
1996-1999	BAR-97	Not applicable.
2000-2009	OIS	Not applicable.
2010 and newer 1	OIS	Vehicles fail when a PDTC is present. 2,3,4,5

1 Some 2010 vehicles do not support PDTC. Those without support for PDTC will not be subject to the PDTC check.

2 A vehicle with a PDTC stored will fail the PDTC check regardless of whether the MIL is commanded ON or OFF.

3 PDTC presence will be ignored if the vehicle has completed at least 15 warm-up cycles and been driven at least 200 miles since its OBD information was last cleared (as determined by Mode $01 PID $30 and $31).

4 BAR is aware of some vehicles that have trouble properly clearing certain PDTCs. BAR is working with the California Air Resources Board (CARB) to ensure that known problematic vehicles are addressed by vehicle manufacturers. Until then, these codes will be ignored by BAR-OIS. For more information, see Permanent Diagnostic Trouble Code Vehicles of Interest.

5 Vehicle manufacturers have issued extended warranties, recalls and repair campaigns for some vehicles that have trouble properly clearing PDTCs. These vehicles are listed under Permanent Diagnostic Trouble Code Vehicles of Interest. When one of these vehicles fails for the PDTC, please refer the motorist to the dealer for covered repairs.

How to Clear PDTCs

To clear PDTCs, you must address the underlying issue that triggered the code and allow the OBD2 system to verify the repair. This typically involves performing a specific drive cycle that allows the system to run its self-tests. The EPA recommends consulting a certified mechanic for accurate diagnosis and repair. After the repair, the PDTC will clear automatically once the system confirms the issue is resolved.

8. Addressing Modified Software Issues

Modified software can cause your vehicle to fail a smog check, as it can interfere with the proper functioning of the OBD2 system and emission controls. The California Bureau of Automotive Repair (BAR) has implemented standards to identify vehicles with illegally modified software. Understanding these standards and how to address modified software issues is crucial for passing the smog check.

What is Modified Software?

On July 19, 2021, a modified software check was added to the BAR-OIS Smog Check inspection. Software approved through a California Air Resources Board (CARB) Executive Order should not cause a vehicle to fail for modified software.

Why is Modified Software a Problem for Smog Checks?

Vehicles identified with illegally modified software will fail the Smog Check inspection. The vehicle inspection report will show Modified Software for the overall inspection result. Once the vehicle is restored to an OEM-approved or CARB-approved software configuration, the vehicle may be retested at any licensed Smog Check station, unless otherwise directed by BAR to a Referee or STAR station. Consumers seeking to dispute inspection results may contact the Smog Check Referee by calling (800) 622-7733.

How to Resolve Modified Software Issues

To resolve modified software issues, restore your vehicle’s software to an OEM-approved or CARB-approved configuration. This may involve reflashing the ECU with the original software or installing a CARB-approved aftermarket tune. The California Bureau of Automotive Repair (BAR) recommends seeking professional assistance from a qualified mechanic to ensure the software is correctly installed. After restoring the software, retest your vehicle at a licensed Smog Check station.

9. Addressing Specific Vehicle Issues

Certain vehicle makes and models have known issues that can affect their ability to pass a smog check. These issues can include problems with readiness monitors, OBD2 communication, or specific diagnostic trouble codes (DTCs). Understanding these common problems and how to address them can help you prepare your vehicle for the smog check.

Ford Vehicles

Ford vehicles, particularly certain models from 2020-2022 like the Escape, Bronco Sport, and E-Series, may experience communication issues with the OBD2 scanner. Ford has issued service bulletins, such as SSM 50974, to address these problems. Check for software updates and ensure your vehicle is running the latest version. If communication issues persist, consult a Ford dealership for diagnosis and repair.

Make	Year	Model Engine (L); Fuel Type	Issue	Cause and Possible Remedy	Instruction to Inspector
Ford	2020-2022	Escape; all engines; Gasoline and hybrid	Might not communicate with BAR-OIS.	Design issue. Software update available.	Test normally. If the vehicle you are inspecting fails the OBD test for no communication, direct the vehicle to a Ford dealership for a software update. Issue may be due to software in gateway module—see SSM 50974. Similar messaging will be displayed on the OIS during the inspection, and printed on the VIR for consumers.
Ford	2021-2022	Bronco Sport; all engines; Gasoline (not hybrid)	Might not communicate with BAR-OIS.	Design issue. Software update available.	Test normally. If the vehicle you are inspecting fails the OBD test for no communication, direct the vehicle to a Ford dealership for a software update. Issue may be due to software in gateway module—see SSM 50974. Similar messaging will be displayed on the OIS during the inspection, and printed on the VIR for consumers.
Ford	2021-2023	E350, E450; all engines; Gasoline (not hybrid)	Might not communicate with BAR-OIS.	Design issue. Software update available.	Test normally. If the vehicle you are inspecting fails the OBD test for no communication, direct the vehicle to a Ford dealership for a software update. Issue may be due to software in gateway module—see SSM 50974. Similar messaging will be displayed on the OIS during the inspection, and printed on the VIR for consumers.

Chevrolet Vehicles

Chevrolet vehicles, particularly the Express and Savana models with diesel engines, may have issues with the exhaust gas sensor monitor not completing. General Motors (GM) has issued recalls, such as N232408230, to address this problem. Ensure your vehicle has had the necessary ECM reprogramming performed. If the exhaust gas sensor monitor remains incomplete, consult a Chevrolet dealership for further assistance.

Make	Year	Model Engine (L); Fuel Type	Issue	Cause and Possible Remedy	Instruction to Inspector
Chevrolet	2019	Express 2.8L (diesel) [California certified]	Exhaust Gas Sensor monitor will not complete. A Particulate Matter sensor fault may not set DTC or illuminate MIL.	The Engine Control Module (ECM) may not properly handle diagnostic information for the exhaust Particulate Matter (PM) sensor. Dealers are to reprogram the ECM per Emission Recall N232408230.	Vehicle requires reflash. Perform recall then retest.

BMW Vehicles

BMW vehicles, especially those from the early 2000s, may experience communication issues or difficulties with readiness monitors. BMW has issued service bulletins, such as SI B12 11 06, to address these problems. Ensure your vehicle has the latest software updates and that all necessary recalls have been performed. If issues persist, consult a BMW specialist for diagnosis and repair.

Make	Year	Model Engine (L); Fuel Type	Issue	Cause and Possible Remedy	Instruction to Inspector
BMW	2001-2003	Z3 M Roadster/coupe with S54 engine	Fail for no communication when ignition switched off/on. OBD communication always possible with BMW DIS or GT1 tester.	Voluntary Emissions Recall Campaign to reprogram the engine control units (DME) on all affected vehicles. Bulletin #SI B12 11 06 dated October 2007.	Follow OIS prompts. Connect/disconnect DAD when key off.
BMW	2000-2003	Z8 & M5 with S62 engine	Fail for no communication when ignition switched off/on. OBD communication always possible with BMW DIS or GT1 tester.	Voluntary Emissions Recall Campaign to reprogram the engine control units (DME) on all affected vehicles. Bulletin #SI B12 11 06 dated October 2007.	Follow OIS prompts. Connect/disconnect DAD when key off.
BMW	From series intro. up to 8/27/2004	M3 with S54 engine	Fail for no communication when ignition switched off/on. OBD communication always possible with BMW DIS or GT1 tester.	Voluntary Emissions Recall Campaign to reprogram the engine control units (DME) on all affected vehicles. Bulletin #SI B12 11 06 dated October 2007.	Follow OIS prompts. Connect/disconnect DAD when key off.

10. Frequently Asked Questions (FAQs) About DMV Smog Requirements OBD2

Navigating the complexities of DMV smog requirements OBD2 can raise many questions. Here are some frequently asked questions to help you better understand the process and ensure your vehicle complies with emission standards.

What is an OBD2 port and where is it located?

The OBD2 port, also known as the diagnostic link connector (DLC), is a standardized interface used to access your vehicle’s computer system. It is typically located under the dashboard on the driver’s side. The Environmental Protection Agency (EPA) requires all vehicles manufactured from 1996 onwards to have an OBD2 port.

How do I use an OBD2 scanner?

To use an OBD2 scanner, plug the device into the OBD2 port, turn on the ignition without starting the engine, and follow the scanner’s instructions to read diagnostic trouble codes (DTCs) and check readiness monitor status. The California Bureau of Automotive Repair (BAR) recommends consulting the scanner’s manual for accurate usage.

What do I do if my car fails the smog check?

If your car fails the smog check, review the inspection report to identify the reasons for failure. Address the issues by repairing any DTC-related problems, completing incomplete readiness monitors, and ensuring proper OBD2 communication. The California DMV recommends consulting a certified mechanic for accurate diagnosis and repair. After addressing the issues, retest your vehicle at a licensed Smog Check station.

How often do I need to get a smog check?

The frequency of smog checks varies by state. In California, most vehicles require a smog check every two years, while some vehicles may need a smog check upon initial registration or change of ownership. The California DMV provides specific guidelines on smog check frequency.

Are there any exemptions from smog check requirements?

Yes, there are exemptions from smog check requirements. In California, vehicles that are less than four years old are exempt from biennial smog checks. Additionally, certain electric vehicles, motorcycles, and vehicles older than a specific model year may be exempt. Check with your state’s DMV for specific exemptions.

Navigating DMV smog requirements with your OBD2 system doesn’t have to be stressful. With the right knowledge and preparation, you can ensure your vehicle complies with emission standards and passes the test smoothly. Remember, OBD2-SCANNER.EDU.VN is always here to help you with expert guidance, diagnostic services, and reliable repairs.

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