On-Board Diagnostics (OBD) systems are integral to modern vehicle maintenance and regulatory compliance. This guide provides a detailed reference for understanding OBD diagnostic testing, including pass/fail criteria for smog check inspections and specific instructions for handling vehicles known to present OBD testing challenges. This document serves as a comprehensive resource for automotive professionals and anyone seeking to understand OBD system diagnostics.
Understanding OBD Readiness Monitors
Readiness monitors are self-diagnostic tests performed by a vehicle’s OBD system to ensure the functionality of emission control systems. These monitors run under specific driving conditions, verifying that components are working correctly to minimize emissions. For most vehicles, these monitors complete during typical driving patterns. However, some vehicles require very specific driving cycles, which may be detailed in the owner’s manual or service literature, to set all monitors to a ‘ready’ status. These drive cycles often involve maintaining specific speeds, engine loads, and temperatures, sometimes necessitating dynamometer equipment for proper execution. It’s also critical to note that monitors will only complete if all related components are functioning correctly. If a component is faulty, the monitor will not set until proper diagnosis and repair are performed. After any repair work, such as disconnecting the battery or replacing emission components, readiness monitors will reset and need to be rerun.
The following table outlines the permissible number of incomplete readiness monitors for a vehicle to pass the OBD portion of a smog check inspection:
| Model Year | Fuel Type | Incomplete Monitors Allowed |
|---|---|---|
| 1996-1999 | Gasoline (including gasoline, propane, natural gas (CNG, LNG, LPG)) | Any one |
| 2000 and newer | Gasoline (including gasoline, propane, natural gas (CNG, LNG, LPG)) | Evaporative system only |
| 1998-2006 | Diesel | Zero |
| 2007 and newer | Diesel | Particulate Filter and Non-Methane HydroCarbon (NMHC) |
Understanding the OBD port is crucial for diagnostic testing.
Malfunction Indicator Lamp (MIL) Standards in OBD Diagnostics
The Malfunction Indicator Lamp (MIL), commonly known as the “Check Engine” light, is a critical component of the OBD system. Its behavior during key-on engine-off (KOEO) and key-on engine-running (KOER) states is a key factor in OBD diagnostic testing. The expected behavior of the MIL is as follows: it should illuminate when the ignition is turned to the ‘on’ position but the engine is not running (KOEO), indicating that the system is functional. Once the engine is started (KOER), the MIL should turn off if no active faults are detected.
Here are the pass/fail standards related to the MIL for OBD testing:
| Condition | Pass/Fail | Standard |
|---|---|---|
| MIL illuminates during KOEO | Pass | MIL should light up when the key is in the ‘on’ position and the engine is off. |
| MIL turns off during KOER | Pass | MIL should turn off once the engine is running, indicating no active emissions faults. |
| MIL does not illuminate during KOEO | Fail | If the MIL fails to light up during KOEO, it indicates a system fault (bulb check failure). |
| MIL illuminates during KOER | Fail | If the MIL remains on or illuminates during KOER, it indicates an active emissions fault that needs attention. |
OBD Communication Standards
Successful OBD diagnostic testing relies on establishing proper communication between the diagnostic tool and the vehicle’s computer system. Communication failure can arise from several issues, ranging from physical problems like a damaged OBD connector or wiring to more complex issues such as aftermarket stereo interference or incorrect computer responses.
The communication standards for OBD testing are as follows:
| Test Type | Standard | Requirement |
|---|---|---|
| BAR-97 | Vehicle communicates with BAR-97 equipment | The vehicle’s OBD system must successfully communicate with the BAR-97 testing equipment. |
| OIS | Vehicle communicates with OIS and transmits required data | The vehicle must communicate with the OIS (On-board Inspection System) and transmit necessary data, typically including Mode $01 PID $00 (supported PIDs) and Mode $01 PID $01 (MIL status, DTCs, and monitor status). |
Permanent Diagnostic Trouble Code (PDTC) Standards
Permanent Diagnostic Trouble Codes (PDTCs) are a specific type of DTC that, unlike regular DTCs, cannot be cleared by simply using a scan tool or disconnecting the vehicle’s battery. PDTCs are designed to ensure that vehicle faults are properly repaired and verified. They will only clear themselves once the OBD II system confirms that the underlying issue has been resolved through normal driving cycles.
Since July 1, 2019, PDTC checks have been incorporated into smog check inspections. The standards for PDTCs are:
| Model Year | Test Type | Standard |
|---|---|---|
| 1996-1999 | BAR-97 | Not applicable |
| 2000-2009 | OIS | Not applicable |
| 2010 and newer | OIS | Vehicles fail if a PDTC is present |
It’s important to note:
- A vehicle will fail the PDTC check if a PDTC is stored, regardless of whether the MIL is currently on or off.
- PDTC checks may be waived if the vehicle has completed at least 15 warm-up cycles and been driven over 200 miles since the last OBD data clear, as indicated by Mode $01 PID $30 and $31.
- There are known vehicle models with issues in clearing certain PDTCs. For these vehicles, exceptions are made during inspections. Refer to the Permanent Diagnostic Trouble Code Vehicles of Interest section for more details.
- Vehicle manufacturers have issued warranties, recalls, and service campaigns to address PDTC clearing issues in some models. Motorists should be directed to dealerships for repairs covered under these programs.
Modified Software Standards in OBD Systems
To maintain emission control system integrity, checks for modified software were introduced into smog check inspections on July 19, 2021. Software modifications that are not approved by the California Air Resources Board (CARB) can cause a vehicle to fail inspection.
Vehicles identified with illegal software modifications will fail the smog check. The inspection report will indicate “Modified Software” as the reason for failure. To pass a subsequent inspection, the vehicle must be restored to an OEM-approved or CARB-approved software configuration. Retesting can be done at any licensed smog check station unless otherwise specified. Consumers who wish to dispute inspection results can contact the Smog Check Referee.
Vehicles of Interest: OBD Diagnostic Challenges
Certain vehicle makes and models have demonstrated recurring issues during OBD testing. These problems range from communication failures and incomplete readiness monitors to OBD test incompatibilities and false MIL illuminations. In many instances, the inspection systems are programmed to accommodate known design anomalies. However, some cases may require vehicle repair.
OIS Vehicles of Interest
The following table lists gasoline, flex-fuel (model year 2000 and newer), and diesel (model year 1998 and newer) vehicles known to have OBD test issues during OIS inspections:
| Make | Year | Model Engine (L); Fuel Type | Issue | Cause and Possible Remedy | Inspector Instructions |
|---|---|---|---|---|---|
| Audi | 2000-2004 | A4 & A6 | No OBD communication | Broken ground wire in ABS module | Repair and retest |
| BMW | 6/1/99 – 7/31/00 | 323i Sedan | Oxygen sensor monitor not set | DME Software error | Check DME number and follow TSB instructions |
| BMW | 9/3/99 – 7/31/00 | 323iT Touring | Oxygen sensor monitor not set | DME Software error | Check DME number and follow TSB instructions |
| BMW | 6/1/99 – 7/29/00 | 323Ci Coupe | Oxygen sensor monitor not set | DME Software error | Check DME number and follow TSB instructions |
| BMW | 6/23/99 – 7/29/00 | 323 Cic Convertible | Oxygen sensor monitor not set | DME Software error | Check DME number and follow TSB instructions |
| BMW | 2000 | M52 (TU) engine | Oxygen sensor monitor not set | DME Software error | Check DME number and follow TSB instructions |
| BMW | 2000 | Readiness failure, oxygen sensor monitor | Software error in ECM | Reflash ECM per Recall #00E-A01 | |
| BMW | built 3/98 – 7/99 | 323i, 323iA, 328i, 328iA | Readiness failure, oxygen sensor monitor | Software error in ECM | Reflash ECM per Recall #00E-A01 |
| BMW | built 2/99 – 7/99 | 328iC, 328iCA, 323iC, 323iCA, 528i, 528iA, 528iT, 528iAT | Readiness failure, oxygen sensor monitor | Software error in ECM | Reflash ECM per Recall #00E-A01 |
| BMW | built 9/98 – 7/99 | Z3 roadster 2.3 | Readiness failure, oxygen sensor monitor | Software error in ECM | Reflash ECM per Recall #00E-A01 |
| BMW | built 4/99 – 7/99 | Z3 roadster coupe/ roadster 2.8 | Readiness failure, oxygen sensor monitor | Software error in ECM | Reflash ECM per Recall #00E-A01 |
| BMW | 2001-2003 | Z3 M Roadster/coupe with S54 engine | No communication when ignition off/on | DME Reprogramming needed | Follow OIS prompts |
| BMW | 2000-2003 | Z8 & M5 with S62 engine | No communication when ignition off/on | DME Reprogramming needed | Follow OIS prompts |
| BMW | From series intro. up to 8/27/2004 | M3 with S54 engine | No communication when ignition off/on | DME Reprogramming needed | Follow OIS prompts |
| BMW | 2003 | M3 | EGR monitor failure | Thermostat issue | Repair and retest |
| BMW | 2007 | 328i | Engine dies during OBD test | Keyless ignition issue | Separate key, wait, test normally |
| Chevrolet | 1998-2005 | DIESEL C/K2500 & C/K3500, G30, G3500, P30 | Not OBD-II certified | Federal diesel vehicle over 8,500 GVWR | Test normally, ignore continuous monitors |
| Chevrolet | 1999-2005 | 3500 W35042 (box truck) | Not OBD-II equipped | OBD not installed in federals | OIS skips OBD functional test |
| Chevrolet | 2000-2002 | S-10 (2WD), 2.2L I-4 (E85) | Monitors not set on flex fuel models | System monitors disabled for operation > E15 blends | OIS ignores all 11 readiness monitors |
| Chevrolet | 2000-2005 | Suburban, Silverado, Express, Avalanche | OBD II requirement uncertainty | Federally certified vehicle may not be OBD II certified | Check under-hood label, follow OIS prompts |
| Chevrolet | 2001 | Silverado / Tahoe C/K 1500 | Secondary air system monitor failure | Air injection problem | Diagnose, repair and retest |
| Chevrolet | 2002 | Silverado C/K 2500HD (diesel) | EGR monitor failure | Difficult drive cycle | OIS allows incomplete monitor |
| Chevrolet | 2001-2002 | Cavalier CNG | CAT monitor failure | Vehicle design anomaly | OIS allows one incomplete monitor |
| Chevrolet | 2019 | Express 2.8L (diesel) | Exhaust Gas Sensor monitor incomplete | ECM diagnostic information issue | Vehicle requires ECM reflash |
| Chrysler | 1999-2000 | Town & Country 3.0L | EGR Monitor incomplete at high altitude | Reflash available | Vehicle requires reflash |
| Chrysler | 2000 | Town and Country 3.3L V-6 (E-85) | Readiness monitors not set on flex fuel models | All monitors disabled for operation >E30 | OIS ignores all 11 readiness monitors |
| Chrysler | 2003 | PT Cruiser 2.4 liter DOHC 16v turbocharged | Catalyst monitor failure | PCM software error | Vehicle requires PCM reflash |
| Chrysler | 2010 built prior to 2/20/2010 | 300, Charger, Challenger 3.5L | Monitor readiness failure, MIL illumination | Reflash available | Vehicle requires reflash |
| Dodge | 1998-2002 | Ram Truck 5.9L (Cummins diesel) | Some continuous monitors incomplete | Vehicle design anomaly | Test normally, BAR-OIS allows one incomplete continuous monitor |
| Dodge | 1998-2006 | Ram 2500, Ram 3500 (diesel) | Not OBD-II certified | Federal diesel vehicle over 8,500 GVWR | Test normally, ignore continuous monitors |
| Dodge | 1999-2000 | Caravan 3.0L | EGR Monitor incomplete at high altitude | Reflash available | Vehicle requires reflash |
| Dodge | 2003 | Dakota, Durango and Ram Trucks 4.7L | Catalyst monitor readiness not supported | Broken vehicle | Test normally, OIS ignores unsupported monitors |
| Dodge | 2003 | Ram Truck 5.9L (Cummins diesel) | MIL light on, no DTCs stored | Vehicle design anomaly | Test normally, OIS ignores MIL command if no DTCs |
| Dodge | 2003-2004 | 25004X2 and Sprinter 35004X2 (diesel) | Not OBD-II certified | Federal diesel vehicle over 8,500 GVWR | Test normally, ignore continuous monitors |
| Dodge | 2004-2005 built after 12/7/2003 | Ram Truck 5.9L (Cummins diesel) | Comprehensive component monitor incomplete | Vehicle design anomaly | Test normally, OIS allows one incomplete monitor |
| Dodge | 2004-2006 | 2500 3500 Sprinter (diesel) | EGR/VVT monitor incomplete | ECU software error | Test normally, OIS ignores EGR/VVT monitor |
| Dodge | 2005 | Ram Truck 5.9L (Cummins diesel) | Misfire and Comprehensive Components monitors incomplete | Vehicle design anomaly | Test normally, OIS ignores misfire and comprehensive component monitor readiness |
| Dodge | 2006-2007 | Ram Truck 5.9L, 6.7L (Cummins diesel) | Fuel System and Comprehensive Components monitors incomplete | Recall campaign #K01 | Test normally, OIS ignores fuel and comprehensive component monitor readiness |
| Dodge | 2006-2007 | Ram Truck 5.9L (ETC or ETH), Cab Chassis 6.7L (ETJ) (Cummins diesel) | Fuel System and Comprehensive Components monitors incomplete | TSB #18-017-10 | Test normally, OIS ignores fuel and comprehensive component monitor readiness |
| Dodge | 2010 built before 2/20/10 | 300, Charger, Challenger 3.5L | Evaporative monitor not set | Evaporative leak detection monitor issue | Test normally, inform consumer of TSB #18-008-10 Revision A |
| Dodge/Ram | 2010-2015 | 2500 & 3500 6.7L (diesel) | NOx after-treatment monitor incomplete | Vehicle design anomaly | Test normally, BAR-OIS temporarily allows NOx after-treatment monitor to be incomplete |
| Dodge/Ram | 2014 | ProMaster 2500 & 3500 High 3.0L (diesel) | Exhaust Gas Sensor monitor incomplete | Vehicle design anomaly | Vehicle requires recalls V97 and ZC0 |
| Dodge/Ram | 2015 | ProMaster 1500, 2500, & 3500 High & Standard 3.0L (diesel) | Exhaust Gas Sensor monitor incomplete | Vehicle design anomaly | Vehicle requires recalls V97 and ZC0 |
| Dodge/Ram | 2016 | ProMaster 2500 & 3500 High 3.0L (diesel) | Exhaust Gas Sensor monitor incomplete | Vehicle design anomaly | Vehicle requires recall V97 |
| Ford | 1998-2003 | Truck 7.3L (diesel) | Engine shut off during Mode $09 data request | Vehicle design anomaly | Test normally, OIS skips Mode $09 data request |
| Ford | 1998-2004 | F250, F350, E350, E450, E Super Duty, Econo Commercial S- Duty, Econo RV S- Duty (diesel) | Not OBD-II certified | Federal diesel vehicle over 8,500 GVWR | Test normally, ignore continuous monitors |
| Ford | 2000-2004 | F250, F350, E350, Excursion | OBD II requirement uncertainty | Federally certified vehicle may not be OBD II certified | Check under-hood label, follow OIS prompts |
| Ford | 2003 | Focus | Readiness failure | Monitors difficult to complete | Reflash PCM per TSB #06-7-5, then test normally |
| Ford | 2004 | E350 Super duty 5.4 (gas) | CAT monitor failure | Vehicle design anomaly Recall #15E06 | Vehicle requires reflash |
| Ford | 2011 | Edge, Explorer 3.5L & 3.7L | Readiness failure | OBD-II data clearing/incorrect VIN reporting | Consult Ford Emission Recall #13E04 |
| Ford | 2013-2016 | F series, Super Duty 6.7L (diesel) | Exhaust Gas Sensor monitor incomplete | Degreening strategy after DOC or DPF replacement | Test normally, OIS ignores EGS monitor |
| Ford | 2015-2019 | Transit 3.2L (diesel) | Exhaust Gas Sensor monitor incomplete | Degreening strategy after DOC or DPF replacement | Test normally, OIS ignores EGS monitor |
| Ford | 2020-2022 | Escape; all engines; Gasoline and hybrid | No communication with BAR-OIS | Design issue, software update available | Direct to Ford dealership for software update |
| Ford | 2021-2022 | Bronco Sport; all engines; Gasoline (not hybrid) | No communication with BAR-OIS | Design issue, software update available | Direct to Ford dealership for software update |
| Ford | 2021-2023 | E350, E450; all engines; Gasoline (not hybrid) | No communication with BAR-OIS | Design issue, software update available | Direct to Ford dealership for software update |
| Ford | 2025 and newer | Explorer (2.3L) AWD, RWD | No OBD communication | Vehicle has OBDonUDS | Cal-VIS software skips OBD test |
| Freightliner | 1998-2004 | M Line Walk In Van | Not OBD-II equipped | OBD not required in federally certified vehicles | OIS skips OBD functional test |
| Freightliner | 2004-2006 | Sprinter (diesel) | EGR/VVT monitor incomplete | ECU software error | Test normally, OIS ignores EGR/VVT monitor |
| GM | 2000 – 2008 | Various models, and Silverado 1500 | No vehicle voltage | No power on OBDII connector | Use auxiliary DAD cables/power supply |
| GM | 2015-2017 | All gasoline powered | Readiness failure | Post catalyst oxygen sensor monitor break-in | Inspect after 1,000 miles or send to Referee |
| GMC | 1998-2005 | DIESEL C/K2500 & C/K 3500, Savana G3500, Workhorse P30 Forward Cntl | Not OBD-II certified | Federal diesel vehicle over 8,500 GVWR | Test normally, ignore continuous monitors |
| GMC | 1999-2005 | W3500 W35042 (box truck) | Not OBD-II equipped | OBD not required in federally certified vehicles | OIS skips OBD functional test |
| GMC | 2000-2002 | Sonoma (2WD), 2.2L I-4 (E85) | Monitors not set on flex fuel models | System monitors disabled for operation > E15 blends | OIS ignores all 11 readiness monitors |
| GMC | 2000-2005 | Sierra, Yukon, Savana | OBD II requirement uncertainty | Federally certified vehicle may not be OBD II certified | Check under-hood label, follow OIS prompts |
| GMC | 2002 | Sierra C/K 2500HD (diesel) | EGR monitor failure | Difficult drive cycle | OIS allows incomplete monitor |
| GMC | 2019 | Savana 2.8L (diesel) | Exhaust Gas Sensor monitor incomplete | ECM diagnostic information issue | Vehicle requires ECM reflash |
| GMC | 2022 | Sierra K2500 SLT 6.6L (diesel) | Exhaust Gas Sensor monitor incomplete | Vehicle design anomaly | Test normally, BAR-OIS temporarily allows Exhaust Gas Sensor monitor to be incomplete |
| Hyundai | 2002 | Sonata | Readiness failure | Monitors difficult to complete | Run drive cycle two times, see TSB #02-36-030 |
| Hyundai | 2003 | Tiburon | No communication with generic OBD equipment | Pin 5 not grounded | Test normally on OIS, recall campaign #057 for generic OBD |
| Infiniti | 2000 -2001 | I30 | Catalyst monitor failure | OEM scan tool only shows OBD catalyst code | Test catalyst, replace if defective |
| Infiniti | 2000 -2001 | I30 | Readiness failure | Monitors difficult to complete | Run drive cycle |
| Isuzu | 1998-2005 | NPR | Not OBD-II equipped | OBD not required in federally certified vehicles | OIS skips OBD functional test |
| Isuzu | 2000-2002 | Hombre (2WD) 2.2L I-4 (E85) | Monitors wont set on flex fuel models | System monitors disabled for operation > E15 blends | OIS ignores all 11 readiness monitors |
| Jaguar | 2017 | Jaguar XE, XF, & F-Pace 2.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall H444 | Direct to Jaguar dealership for software update |
| Jaguar | 2018 | Jaguar XE, XF, F-Pace & Rover Velar 2.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall H444 | Direct to Jaguar dealership for software update |
| Jaguar | 2019 | Jaguar XE, XF, & F-Pace 2.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall H444 | Direct to Jaguar dealership for software update |
| Jeep | 2005-2006 | Wrangler | O2 sensor, O2 heater, and catalyst readiness monitors incomplete | Vehicle design anomaly, TSB #25-005-13 Rev. A | OIS allows incomplete O2 heater monitor |
| Jeep | 2010-2011 | Wrangler 3.8L | Oxygen sensor monitor failure | PCM not running monitor frequently enough | Reflash PCM per TSB 18-027-10, special drive cycle may be needed |
| Kia | 2009 | Borrego LX/EX 3.8L | Readiness failure | EGR monitor difficult to complete | OIS allows EGR/VVT monitor to be incomplete |
| Land Rover | 2017 | Discovery, Range Rover, Range Rover Sport 3.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall N808 | Direct to Land Rover dealership for software update |
| Land Rover | 2018 | Velar 2.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall N808 | Direct to Land Rover dealership for software update |
| Land Rover | 2019 | Velar 2.0L (diesel) | NOx Aftertreatment System monitor incomplete | Vehicle design anomaly, Dealer recall N808 | Direct to Land Rover dealership for software update |
| Lexus | 2007 | RX400 Hybrid | Oxygen sensor monitor readiness failure | Air Fuel monitor issue | Advise motorist recall may be required, recall status: toyota.com/recall |
| Lincoln | 2011 | MKX 3.5L & 3.7L | Readiness failure | OBD-II data clearing/incorrect VIN reporting | Consult Ford Emission Recall #13E04 |
| Lincoln | 2020-2022 | Corsair; all engines; Gasoline and hybrid | No communication with BAR-OIS | Design issue, software update available | Direct to Ford dealership for software update |
| Mazda | 2000 | MPV | Catalyst monitor failure | May need catalyst and/or oxygen sensor | Repair and retest |
| Mazda | 2002-2003 | B3000 (2WD) 3.0L V-6 (E-85) | Readiness monitors not set on flex fuel models | Monitors disabled for operation >E10 blends | OIS ignores all 11 readiness monitors |
| Mazda | 2003-2004 | Mazda 6 | False MIL illumination | PCM sensitive to OBD tool connect/disconnect | Reset monitors, connect/disconnect DAD when key off |
| Mazda | 2005 | Mazda 6 (with 2.3 only) | False MIL illumination | PCM sensitive to OBD tool connect/disconnect | Reset monitors, connect/disconnect DAD when key off |
| Mazda | 2003-2005 | Mazda 6 – 2.3 engine non PZEV, Mazda 6 – 3.0 engine | False MIL illumination | PCM sensitive to OBD tool connect/disconnect | Follow OIS prompts, connect/disconnect DAD when key off |
| Mitsubishi Fuso | 1998-2004 | FE639/FG639 | Not OBDII equipped | OBD not required in federally certified vehicles | OIS skips OBD functional test |
| Mitsubishi | 2000-2001 | Montero, Montero Sport, Diamante, 3000GT Mirage, Galant, Expo/Expo LRV, and Eclipse models | Readiness failure | Monitors difficult to complete | Follow recommended drive cycles |
| Nissan | 1999-2007 | UD1200 | Not OBDII equipped | OBD not required in federally certified vehicles | OIS skips OBD functional test |
| Nissan | 2000-2001 | Maxima | Catalyst monitor failure | OEM scan tool only shows OBD catalyst code | Test catalyst, replace if defective |
| Nissan | 2000-2006 | All models | Readiness failure | Incomplete monitors during normal driving | Follow drive cycle |
| Plymouth | 1999-2000 | Voyager 3.0L | EGR Monitor incomplete at high altitude | Reflash available | Vehicle requires reflash |
| Plymouth | 2000 | Voyager 3.3L V-6 (E-85) | Readiness monitors not set on flex fuel models | All monitors disabled for operation >E30 | OIS ignores all 11 readiness monitors |
| Suzuki | 2001 | Aerio | Readiness failure | Monitors can be difficult to complete | Follow drive cycle |
| Suzuki | 2004 | Forenza | Readiness failure | Monitors can be difficult to complete | Follow drive cycle |
| Toyota | 2000-2006 | All models | Readiness failure | Monitors can be difficult to complete | Follow drive cycle |
| Toyota | 2003-2004 | 4 Runner | VSC light illumination | CAN protocol issue with aftermarket scan tool | OIS will not attempt CAN protocol |
| Toyota | 2007 | Highlander Hybrid | Oxygen sensor monitor readiness failure | Air Fuel monitor issue | Advise motorist recall may be required, recall status: toyota.com/recall |
| Volvo | 2000 | S40 / V40 | Comprehensive, Oxygen sensor, and Catalyst monitors failure | Defective ECM | Send to Referee if only these monitors unset |
| Volvo | 2004-2006 | S40, V50 | Air conditioning monitor mistakenly set to supported | Vehicle design anomaly | OIS ignores A/C monitor status |
| Volvo | 2005-2007 | XC90 | Air conditioning monitor mistakenly set to supported | Vehicle design anomaly | OIS ignores A/C monitor status |
| VW | 2000-2005 | Passat | No OBD communication | Broken ground wire in ABS module | Repair and Retest |
An OBD diagnostic tool is essential for modern vehicle repair.
Permanent Diagnostic Trouble Code Vehicles of Interest
Certain vehicles are known to have issues with permanent diagnostic trouble codes (PDTCs) that do not clear as expected. In these cases, inspection systems may be programmed to ignore specific PDTCs to avoid unwarranted failures. The following table outlines vehicles with known PDTC issues:
| Make | Year | Model Engine (L); Fuel Type | Issue | Cause and Possible Remedy | Inspector Instructions |
|---|---|---|---|---|---|
| Audi | 2010 | Q7; 3.0 (TDI/diesel) | PDTCs P0087, P0088, and P053F will not clear | No remedy available | Test normally, BAR-OIS ignores these codes |
| Audi | 2011-2012 | Q7; 3.0 (TDI/diesel) | PDTCs P0087, P0088, P053F, P064A, P2635, and P0230 will not clear | No remedy available | Test normally, BAR-OIS ignores these codes |
| Chrysler | 2011-2015 | 200; 2.4, 3.6 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Chrysler | 2010-2014 | 300; 3.6, 5.7, 6.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Chrysler | 2017 | Pacifica Hybrid | PDTC C2200 or B22A9-00 failure | Reflash modules per TSB 08-005-21 and 08-006-21 | Reflash then retest |
| Chrysler | 2018 | Pacifica Hybrid | PDTC C2200 or B22A9-00 failure | Reflash modules per TSB 08-008-21 and 08-009-21 | Reflash then retest |
| Chrysler | 2019 | Pacifica Hybrid | PDTC C2200 or B22A9-00 failure | Reflash modules per TSB 08-011-21 and 08-012-21 | Reflash then retest |
| Chrysler | 2011-2015 | Town and Country; 3.6 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2014 | Avenger | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2012 | Caliber; 2.0, 2.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2015 | Challenger; 3.6, 5.7, 6.4 | PDTC U0140 failure | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2014 | Charger; 3.6, 5.7, 6.4 | PDTC U0140 failure | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2015 | Grand Caravan; 3.6 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2010-2011 | Dakota; 3.7, 4.7 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2013 | Dart; 2.0 | PDTC U0140 failure | Reflash per Recall V50 and V51 | Reflash then retest |
| Dodge | 2013 | Dart; 2.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2014-2015 | Dart; 2.0, 2.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2014 | Durango; 3.6, 5.7 | PDTC U0140 failure | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2011-2015 | Journey; 2.4, 3.6 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Dodge | 2010-2011 | Nitro; 3.7, 4.0 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Ford | 2011-2014 | Mustang; 3.7 & 5.0 (gasoline) | PDTC P0315 failure | Vehicle not self-clearing permanent fault code | Refer motorist to Ford Customer Satisfaction Program 17N01 |
| Freightliner | 2014-2015 | Sprinter 2500 Sprinter 3500 (diesel) | PDTC failures P202A, P203A, P208A, P20B9, P20BD, P20BE or P20FA | Vehicle not self-clearing permanent fault code | Test normally, BAR-OIS ignores these codes |
| Jeep | 2014-2015 | Cherokee; 2.4, 3.2 | PDTC U0140 failure | Reflash per Recall V51 | Reflash then retest |
| Jeep | 2010 | Commander; 5.7 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Jeep | 2010-2015 | Grand Cherokee; 3.6, 5.7, 6.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Jeep | 2014-2017 | Grand Cherokee (diesel) | PDTC P1D30 failure | Vehicle not self-clearing permanent fault code | Test normally, BAR-OIS ignores this code |
| Jeep | 2010-2012 | Liberty; 3.7 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Jeep | 2011-2015 | Patriot / Compass; 2.0, 2.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Jeep | 2010-2015 | Wrangler; 3.6, 3.8 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Mercedes | 2010-2013 | 350 Bluetec | PDTC failures P203D, P20B6, P20BD or P20BE | Vehicle not self-clearing permanent fault code | Test normally, BAR-OIS ignores these codes |
| Mercedes | 2014-2015 | Sprinter 2500 Sprinter 3500 (diesel) | PDTC failures P202A, P203A, P208A, P20B9, P20BD, P20BE or P20FA | Vehicle not self-clearing permanent fault code | Test normally, BAR-OIS ignores these codes |
| Ram | 2010-2014 | 1500; 3.6, 3.7, 4.7, 5.7 | PDTC U0140 failure | Reflash per Recall V51 | Reflash then retest |
| Ram | 2013 | 1500; 3.6, 5.7 | Permanent Fault Codes will not clear | Reflash per Recall V50 | Reflash then retest |
| Ram | 2014-2017 | 1500 (diesel) | PDTC P1D30 failure | Vehicle not self-clearing permanent fault code | Test normally, BAR-OIS ignores this code |
| Ram | 2010-2015 | 2500; 5.7, 6.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Ram | 2011-2015 | 3500 Cab Chassis; 5.7, 6.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Ram | 2013-2015 | 3500 Pickup; 5.7, 6.4 | Permanent Fault Codes will not clear | Reflash per Recall V51 | Reflash then retest |
| Ram | 2014 | Promaster; 3.6 | Permanent Fault Codes will not clear | Reflash per Recall V50 | Reflash then retest |
| Volkswagen | 2010 | Touareg; 3.0 (TDI/diesel) | PDTCs P20B5, P0087, P0088, and P053F will not clear | No remedy available | Test normally, BAR-OIS ignores these codes |
| Volkswagen | 2011-2012 | Touareg; 3.0 (TDI/diesel). | PDTCs P20B5, P0087, P0088, P053F, P064A, P2635, and P0230 will not clear | No remedy available | Test normally, BAR-OIS ignores these codes |
BAR-97 EIS Vehicles of Interest
For vehicles manufactured between 1996 and 1999, specific monitor readiness issues can occur during BAR-97 EIS inspections. In many of these cases, the BAR-97 EIS system is designed to accommodate these known vehicle design anomalies. The following table lists vehicles with monitor readiness issues relevant to BAR-97 EIS inspections:
| Make | Year | Model Engine (L); Fuel Type | Issue | Cause and Possible Remedy | Inspector Instructions |
|---|---|---|---|---|---|
| BMW | 1996 | 7-Series, 8-Series 5.0L, 5.4L | Monitors difficult to complete | EIS ignores readiness status | |
| Chrysler | 1996 | Cirrus, Concord, LHS Sebring Convertible | Monitors reset upon ignition key-off | Recall campaign #678/TSB #18-005-01 | Comply with recall, then test as normal |
| Chrysler | 1996 | Concord, LHS, New Yorker, Sebring, Town & Country 2.0L, 2.4L, 2.5L, 3.3L, 3.5L | Monitors difficult to complete | EIS ignores readiness status | |
| Chrysler | 1998-1999 | Town & Country 3.3L Flex Fuel | Monitors may not function with ethanol | Test as normal | |
| Dodge | 1996 | Stratus, Intrepid, Neon | Monitors reset upon ignition key-off | Recall campaign #678/TSB #18-005-01 | Comply with recall, then test as normal |
| Dodge | 1996 | Avenger, Stratus 2.0L manual | Monitors difficult to complete | EIS ignores readiness status | |
| Dodge | 1996 | Stealth 3.0L | Monitors reset upon ignition key-off | Not reflashable | EIS ignores readiness status |
| Dodge | 1998-1999 | Caravan 3.3L Flex Fuel | Monitors may not function with ethanol | Test as normal | |
| Eagle | 1996 | Vision | Monitors reset upon ignition key-off | Recall campaign #678/TSB #18-005-01 | Comply with TSB, then test as normal |
| Eagle | 1996-1997 | Talon 2.0L | Monitors difficult to complete | EIS ignores readiness status | |
| Ford | 2020-2022 | F-53 Motorhome, F-59 Commercial Stripped Chassis; Gasoline (not hybrid) | No OBD communication | Design issue, software update available | Direct to Ford dealership for software update |
| Ford | 2021-2023 | F-650, F-750; all engines; Gasoline (not hybrid) | No OBD communication | Design issue, software update available | Direct to Ford dealership for software update |
| Hyundai | 1996 | Accent 1.5L Elantra 1.8L Sonata 2.0L | Monitors difficult to complete | EIS ignores readiness status | |
| Hyundai | 1997-1998 | Sonata 2.0L, 3.0L | Monitors difficult to complete | EIS ignores readiness status | |
| lnfiniti | 1996 | All models | Catalyst and evaporative system monitors difficult | Follow drive cycle per TSB #ITB98-011F | Test as normal |
| Kia | 1996 | Sephia Sportage | Monitors difficult to complete | EIS ignores readiness status | |
| Lexus | 1996-1999 | All models | Monitors can be difficult to complete | Follow drive cycles in Lexus service information | Test as normal |
| Mercedes-Benz | 1996 | C220, E320, C280, S320, SL320 | MIL illuminates with scan tool connection, no codes | OBD II connector RPM source issue | Connect OBD II only when prompted, use alternate RPM method |
| Mitsubishi | 1996-1997 | All Models | Monitors difficult to complete | EIS ignores readiness status | |
| Mitsubishi | 1998 | Eclipse (all), Galant 2.4L, Mirage, Montero Sport 2.4L | Monitors difficult to complete | EIS ignores readiness status | |
| Mitsubishi | 1998 | 3000GT, Diamante, Galant 2.3L, Montero, Montero Sport 3.0L | Some monitors difficult to complete | Follow recommended drive cycles | Test as normal |
| Mitsubishi | 1999 | All models | Some monitors difficult to complete | Follow recommended drive cycles | Test as normal |
| Nissan | 1996 | Sentra 1.6L and 2.0L manual, 200SX 1.6L, 240SX 2.4L, Maxima 3.0L, Pickup 2.4L | Monitors difficult to complete | EIS ignores readiness status | |
| Nissan | 1996-1997 | All models | Catalyst and evaporative system monitors difficult | Follow drive cycle per Nissan TSB #NTB98-018G | Comply with TSB, then test as normal |
| Nissan | 1999 | All models | Monitors can be difficult to complete | Follow owner’s manual drive cycle | Test as normal |
| Plymouth | 1996 | Breeze, Neon | Monitors reset upon ignition key-off | Recall campaign #678/TSB #18-005-01 | Comply with recall, then test as normal |
| Plymouth | 1998-1999 | Voyager 3.3L Flex Fuel | Monitors may not function with ethanol | Test as normal | |
| Saab | 1996-1998 | 900 2.3L (B234 with Motronic 4.1) | Monitors difficult to complete | EIS ignores readiness status | |
| Saab | 1996-1998 | All models | Catalyst and evaporative system monitors difficult | Saab Service Instruction No. 248-9037 | Comply with TSB, then test as normal |
| Subaru | 1996 | All models | Readiness cleared at key-off | EIS ignores readiness status | |
| Toyota | 1996-1999 | All models | Monitors can be difficult to complete | Follow drive cycles in Toyota service information | Test as normal |
| Toyota | 1996-1997 | Tercel, Paseo | Evaporative system monitor never completes/unsupported | EIS allows one incomplete monitor | Test as normal |
| VW | 1997-1999 | Passat | No OBD communication | Broken ground wire in ABS module | Repair and retest |
| Volvo | 1996-1998 | All models | Monitors difficult to complete | Follow drive cycles in Service Bulletin 25-19 | EIS ignores readiness status |
This guide is intended to provide a comprehensive overview of OBD diagnostic testing standards and to assist inspectors and technicians in addressing common challenges. Regular updates will be made to this document to reflect new vehicle models and evolving diagnostic procedures.
