Ensuring your vehicle is ready for a smog check is crucial for compliance and environmental responsibility. The On-Board Diagnostic system, or OBDII, plays a central role in modern smog inspections. This guide provides a comprehensive overview of how to prepare your car for an OBDII smog check, focusing on making your car “Ready Car Obdii For Smog Check The Entire Process.” We’ll cover everything from understanding readiness monitors to troubleshooting common issues, ensuring you navigate the smog check process with confidence.
Understanding the OBDII Smog Check
The OBDII smog check is a vital part of vehicle emission testing in many regions. It involves connecting a diagnostic tool to your vehicle’s OBDII port to assess the performance of its emission control systems. This system monitors various components and reports any malfunctions through diagnostic trouble codes (DTCs) and the Malfunction Indicator Lamp (MIL), commonly known as the “Check Engine” light.
The OBDII test is designed to ensure that your vehicle’s emission control systems are functioning correctly, thereby reducing harmful pollutants released into the atmosphere. A key aspect of passing the OBDII test is ensuring that your vehicle’s readiness monitors are set.
Key Components of an OBDII Smog Check and Pass/Fail Standards
To effectively prepare your car, it’s essential to understand the specific components evaluated during an OBDII smog check. These include readiness monitors, the Malfunction Indicator Lamp (MIL), communication standards, permanent diagnostic trouble codes (PDTCs), and modified software checks.
Readiness Monitors: Ensuring Your Car is “Ready”
Readiness monitors are self-tests performed by your vehicle’s OBDII system to confirm that emission control systems are functioning correctly. These monitors run in the background during normal driving conditions. For a vehicle to pass the OBDII portion of a smog check, a certain number of these monitors must be in a “ready” state, indicating that the tests have been completed and no issues were detected.
Image alt text: The check engine light, or Malfunction Indicator Lamp (MIL), illuminated on a car dashboard, signaling a potential issue that could affect smog check readiness.
The number of incomplete monitors allowed varies depending on the model year and fuel type of your vehicle. Understanding these standards is the first step in making your car OBDII smog check ready.
Readiness Monitor Standards Table:
| Model Year | Fuel Type | Number of Incomplete Monitors Allowed to Pass OBD Test |
|---|---|---|
| 1996-1999 | Gas | Any one |
| 2000 and newer | Gas | Evaporative system |
| 1998-2006 | Diesel | Zero |
| 2007 and newer | Diesel | Particulate Filter and NMHC |
Note: “Gas” includes gasoline, propane, natural gas (CNG, LNG, LPG).
For gasoline vehicles from 2000 and newer, only the Evaporative system monitor can be incomplete. For newer diesel vehicles (2007 and newer), the Particulate Filter and Non-Methane Hydrocarbon (NMHC) monitors are the only ones allowed to be incomplete. All other specified monitors must be in a “ready” state for the vehicle to pass the OBDII test.
Malfunction Indicator Lamp (MIL) Standards: The “Check Engine” Light
The Malfunction Indicator Lamp (MIL), or “Check Engine” light, is a critical indicator of your vehicle’s emission system health. The smog check includes a check of the MIL’s behavior in two key states: Key On Engine Off (KOEO) and Key On Engine Running (KOER).
Malfunction Indicator Lamp (MIL) Standards Table:
| 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). |
For a passing grade, the MIL should illuminate briefly when the key is turned to the “on” position before engine start (KOEO) and then turn off once the engine is running (KOER), provided there are no active emission-related faults. If the MIL is on when the engine is running, or if it fails to illuminate at all during KOEO, the vehicle will fail the OBDII smog check.
Communication Standards: Establishing Connection
Successful communication between the smog check analyzer and your vehicle’s OBDII system is fundamental. A “no communication” failure can occur due to various issues, ranging from a damaged OBDII connector to more complex vehicle system problems.
Communication Standards Table:
| 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. |
Required data typically includes information from OBD addresses Mode $01 PID $00 and Mode $01 PID $01. These PIDs provide data on supported parameters, MIL status, DTCs, and monitor status. If the analyzer cannot communicate with the vehicle and retrieve this data, the vehicle will fail the communication portion of the OBDII test.
Permanent Diagnostic Trouble Code (PDTC) Standards: Unclearable Codes
Permanent Diagnostic Trouble Codes (PDTCs) are a specific type of DTC that cannot be cleared using a scan tool or by disconnecting the vehicle’s battery. PDTCs are designed to ensure that emission issues are properly addressed and verified as resolved by the vehicle’s OBDII system itself over time.
Permanent Diagnostic Trouble Code (PDTC) Standards Table:
| Model Year | BAR-97/OIS | Standard |
|---|---|---|
| 1996-1999 | BAR-97 | Not applicable. |
| 2000-2009 | OIS | Not applicable. |
| 2010 and newer | OIS | Vehicles fail when a PDTC is present. |
For vehicles model year 2010 and newer, the presence of any PDTC will result in an automatic failure of the OBDII smog check, regardless of whether the MIL is currently illuminated. This standard ensures that historical emission faults are resolved and verified by the vehicle’s system. There are exceptions for vehicles that have completed a certain number of warm-up cycles and mileage since the last OBD data clear, and some vehicle-specific exceptions are noted in later sections.
Modified Software Standards: Ensuring OEM Compliance
To prevent tampering with emission control systems, smog checks also include a check for modified software. Illegally modified software that alters emission controls will cause a vehicle to fail the smog check.
Modified Software Standards:
- Vehicles with illegally modified software will fail the Smog Check inspection.
- The vehicle inspection report will indicate “Modified Software” as the overall inspection result.
- To pass, the vehicle must be restored to an OEM-approved or CARB-approved software configuration.
This check ensures that the vehicle’s emission control software is in its original, compliant state, maintaining the intended emission performance.
Preparing Your Car for an OBDII Smog Check: The Entire Process
Getting your car ready for an OBDII smog check involves several key steps. The goal is to ensure all readiness monitors are set, no DTCs or PDTCs are present, and the MIL is functioning correctly. Here’s a step-by-step process:
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Check for the Check Engine Light (MIL): Before anything else, check your dashboard for the “Check Engine” light. If it’s illuminated while the engine is running, it indicates a problem that needs to be addressed before the smog check. Use an OBDII scanner to read any stored Diagnostic Trouble Codes (DTCs).
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Address any DTCs: If DTCs are present, diagnose and repair the underlying issues. Common problems can range from loose gas caps to faulty oxygen sensors or catalytic converters. Addressing these issues is crucial for passing the smog check. Tools like Autel’s OBDII scanners can be invaluable in diagnosing these problems accurately.
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Verify Readiness Monitors: After repairs, or even as preventative maintenance, check the status of your vehicle’s readiness monitors using an OBDII scanner. Most scanners can display the status of each monitor, showing whether it’s “ready” or “not ready.”
Image alt text: An Autel OBDII scanner in use, displaying vehicle diagnostic data, which can include readiness monitor status, crucial for pre-smog check verification.
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Perform a Drive Cycle (If Necessary): If some readiness monitors are “not ready,” you may need to perform a drive cycle. A drive cycle is a specific set of driving conditions designed to allow the vehicle’s OBDII system to run all the necessary self-tests and set the monitors to “ready.” Drive cycles vary by manufacturer and model, and information can often be found in the vehicle’s owner’s manual or online repair databases. Sometimes, simply driving your car under normal conditions for a few days can also set the monitors.
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Clear DTCs and Re-check Readiness (If Necessary): If you performed repairs or a drive cycle to set monitors, you might need to clear any DTCs that were present and then re-check the readiness monitor status. Be aware that clearing DTCs will also reset readiness monitors, requiring you to drive the vehicle again to set them. Avoid clearing codes right before a smog check unless you are certain the monitors will reset in time and within the allowable incomplete monitor limits.
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Allow Time for Monitors to Set: After performing a drive cycle or disconnecting the battery (which also resets monitors), allow sufficient time for the monitors to set before taking your car for a smog check. Driving for a few days under varied conditions is generally recommended.
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Pre-Smog Check with a Diagnostic Tool: Consider performing a pre-smog check using your OBDII scanner right before your official test. This allows you to confirm that all readiness monitors are set, no DTCs or PDTCs are present, and the MIL is functioning correctly, giving you peace of mind before the official inspection.
By following these steps, you can significantly increase your chances of passing the OBDII smog check and ensure your vehicle is indeed “ready car obdii for smog check the entire process.”
Common OBDII Smog Check Issues and Vehicle-Specific Guidance
While the general preparation steps are effective for most vehicles, certain makes and models have known issues that can affect their ability to pass an OBDII smog check. These issues can range from difficulties in setting readiness monitors to communication problems or false MIL illuminations.
The original document provides extensive tables detailing vehicle-specific issues. Here’s a summary of common problem areas and how to approach them:
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Readiness Monitor Incompletion: Some vehicles, especially older models or specific makes like BMW, Chevrolet, Chrysler, Dodge, Ford, Hyundai, Infiniti, Kia, Lexus, Mazda, Mitsubishi, Nissan, Plymouth, Suzuki, Toyota, and Volvo, may have difficulty setting certain readiness monitors. For these vehicles, understanding the specific monitor that is not setting and whether it’s permissible to be incomplete based on the standards table is crucial. Sometimes, specific drive cycles or software updates (reflashes) from the manufacturer are required. The tables in the original document offer detailed instructions and TSB references for many of these cases.
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No Communication Issues: Vehicles from Audi, BMW, Ford, GM, VW, and others have been known to experience “no communication” errors during OBDII tests. This can be due to various reasons, including wiring problems, software glitches, or aftermarket accessories interfering with the OBDII port. The tables provide vehicle-specific causes and remedies, often pointing to software updates or specific diagnostic procedures. For certain Ford models (Escape, Bronco Sport, E-Series, Corsair, F-Series), software updates are often the solution, and directing the vehicle to a dealership for these updates is recommended if a “no communication” issue arises. For older Audi and VW models, broken ground wires in the ABS module are a known cause.
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Permanent Diagnostic Trouble Code (PDTC) Issues: Certain Chrysler, Dodge, Jeep, Ram, Mercedes, and Volkswagen models are known to have issues with PDTCs that may not clear even after the underlying problems are resolved. In many of these cases, software reflashes are available from the manufacturers to address these PDTC issues. The tables list specific models and the relevant recall or TSB information. For some Audi, Mercedes, and VW diesel models, certain PDTCs are known to not clear and are, therefore, ignored by the smog check system.
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Modified Software Detection: Vehicles with aftermarket tunes or modified engine control software will fail the modified software check. Restoring the vehicle to its original OEM software configuration is necessary to pass.
Vehicle Specific Tables (Examples – Refer to Original Document for Full Lists):
The original document contains extensive tables listing vehicles of interest for OIS, PDTC, and BAR-97 EIS inspections. These tables are invaluable for technicians and inspectors. Here are a few examples from those tables to illustrate the type of vehicle-specific information provided:
OIS Vehicles of Interest (Example):
| 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 no communication, direct to Ford dealer for software update. |
| Chevrolet | 2019 | Express 2.8L (diesel) | Exhaust Gas Sensor monitor will not complete. | ECM software issue. Recall N232408230. | Vehicle requires reflash. Perform recall then retest. |
| BMW | 2007 | 328i | Engine dies during OBD Test, won’t restart. | Keyless ignition issue. | Separate key and vehicle, wait 20+ mins, restart. Test normally. |
Permanent Diagnostic Trouble Code Vehicles of Interest (Example):
| Make | Year | Model Engine (L); Fuel Type | Issue | Cause and Possible Remedy | Instructions to Inspector |
|---|---|---|---|---|---|
| Chrysler | 2011-2015 | 200; 2.4, 3.6 | Permanent Fault Codes will not clear. | Reflash per Recall V51. | Reflash then retest. |
| Freightliner | 2014-2015 | Sprinter 2500 Sprinter 3500 (diesel) | Vehicle fails for PDTCs P202A, etc. | Vehicle not self-clearing PDTC. | Test normally. BAR-OIS ignores these codes. |
BAR-97 EIS Vehicles of Interest (Example):
| Make | Year | Model Engine (L); Fuel Type | Issue | Cause and Possible Remedy | Instructions to Inspector |
|---|---|---|---|---|---|
| Chrysler | 1996 | Cirrus, Concord, LHS Sebring Convertible | Monitors reset to incomplete at key-off. | Recall #678/TSB #18-005-01. | Comply with recall, then test. |
| Toyota | 1996-1997 | Tercel, Paseo | Evaporative monitor never completes/unsupported. | EIS allows one incomplete monitor. | Test as normal. |
Consulting these tables in the original document is essential for diagnosing and addressing OBDII smog check issues on specific vehicles, particularly those known to have anomalies.
Conclusion: Ensuring a “Ready Car OBDII for Smog Check”
Preparing your car for an OBDII smog check is a proactive process that ensures your vehicle meets emission standards and contributes to cleaner air. By understanding the components of the OBDII test—readiness monitors, MIL function, communication, PDTCs, and software compliance—and following the steps outlined in this guide, you can significantly increase your chances of passing.
For specific vehicle issues, especially those listed in the detailed tables provided in the original reference document, consulting those resources is crucial. Utilizing OBDII diagnostic tools like those from Autel can further streamline the process, allowing for accurate diagnosis, readiness monitor verification, and efficient repairs. Ultimately, a well-prepared and maintained vehicle is a “ready car obdii for smog check the entire process,” leading to a successful smog inspection and a healthier environment.
