Understanding your car’s emissions and ensuring they meet legal standards is crucial. A Car Diagnostic Smog Test Tool empowers you to do just that. This comprehensive guide delves into the intricacies of these tools, outlining pass/fail standards for Smog Check inspections and providing solutions for common vehicle diagnostic challenges.
Demystifying Readiness Monitors: How They Work and Why They Matter
Your car’s On-Board Diagnostic (OBD) system utilizes readiness monitors – self-tests that evaluate the functionality of emission control components. While regular driving often suffices for monitor completion, some vehicles require specific operating conditions. Factors like speed, temperature, and engine load influence monitor readiness. Consulting your owner’s manual or repair service literature for specific drive cycle information can be beneficial. Malfunctioning components can also hinder monitor completion, necessitating thorough diagnosis and repair. Remember, disconnecting the battery or replacing emission components requires rerunning the readiness monitors.
Smog Check Inspection: OBD Pass/Fail Criteria
The table below outlines the permissible number of incomplete OBD readiness monitors for passing a Smog Check inspection.
| 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.
Malfunction Indicator Lamp (MIL): Deciphering the “Check Engine” Light
The Malfunction Indicator Lamp (MIL), commonly known as the “Check Engine” light, plays a vital role in the OBD test. The following table summarizes the pass/fail standards related to the MIL:
| 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). |
Establishing Communication: Ensuring Your Car and Scanner Connect
A failed communication attempt during the OBD test can stem from various issues, including a damaged OBD connector, aftermarket stereo interference, or invalid vehicle data. The table below outlines the communication standards:
| 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.
Permanent Diagnostic Trouble Codes (PDTCs): Understanding Lasting Issues
Introduced on July 1, 2019, the PDTC check became an integral part of the BAR-OIS Smog Check inspection. PDTCs, similar to regular Diagnostic Trouble Codes (DTCs), indicate persistent issues. Unlike DTCs, clearing PDTCs requires the OBD II system to confirm the resolution of the identified defects.
| Model Year | BAR-97/OIS | Standard |
|---|---|---|
| 1996-1999 | BAR-97 | Not applicable. |
| 2000-2009 | OIS | Not applicable. |
| 2010 and newer1 | 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.
Modified Software: Ensuring Compliance with Emission Standards
Effective July 19, 2021, the modified software check was implemented in the BAR-OIS Smog Check inspection. Software approved by the California Air Resources Board (CARB) through an Executive Order should not result in a failed inspection. However, vehicles with illegally modified software will fail.
Troubleshooting Common OBD Issues: Vehicle-Specific Guidance
Numerous gasoline, flex-fuel, and diesel vehicles experience specific issues during the OBD test portion of a Smog Check inspection. These issues range from communication failures to incomplete readiness monitors. Consult the comprehensive tables in Sections D, E, and F for detailed information on specific vehicle makes, models, years, and associated problems. These sections provide valuable insights into the causes of these issues and potential remedies, enabling effective troubleshooting and ensuring your vehicle’s compliance with emission standards.
Conclusion: Empowering Car Owners with Diagnostic Tools
Car diagnostic smog test tools are indispensable for understanding and addressing vehicle emission issues. By familiarizing yourself with the information presented in this guide, you’ll be better equipped to navigate the complexities of Smog Check inspections, troubleshoot common problems, and ensure your car operates efficiently and within legal limits. Remember to consult the vehicle-specific tables for targeted guidance and solutions to known issues.
