Decoding Auto Codes OBD2: Your Comprehensive Guide to On-Board Diagnostics

Understanding your vehicle’s health is becoming increasingly reliant on its On-Board Diagnostic system, or OBD2. This system, mandated in most modern vehicles, monitors various aspects of your car’s performance and emissions, alerting you to potential problems through “Auto Codes Obd2,” commonly known as diagnostic trouble codes (DTCs). This guide will delve into the world of OBD2, explaining the pass/fail standards for smog checks and offering insights into common issues and vehicle-specific concerns related to OBD testing.

Understanding OBD Test Standards for Smog Checks

The OBD test is a crucial part of vehicle inspections, particularly smog checks, designed to ensure vehicles are running cleanly and efficiently. Let’s break down the key components of these standards.

Readiness Monitor Standards

Readiness monitors are essentially self-checks performed by your vehicle’s OBD system. These monitors verify that emission control systems are functioning correctly. While many vehicles complete these self-tests during normal driving, some may require specific driving conditions or experience difficulties due to vehicle design or driving habits. Vehicle owner’s manuals sometimes contain drive cycle procedures to help complete these monitors, but often this information is only available to manufacturers or within professional repair resources. Completing drive cycles requires specific conditions such as speed, temperature, and engine load, which might necessitate dynamometer equipment in certain situations. Furthermore, properly functioning components are essential for monitor completion; a vehicle may fail to complete a monitor until underlying issues are diagnosed and repaired. It’s also important to remember that readiness monitors must be rerun after any repair work that involves disconnecting the battery or replacing emission components.

The number of incomplete readiness monitors allowed to pass an OBD test during a smog check varies depending on the vehicle’s model year and fuel type:

Model Year Fuel Type Incomplete Monitors Allowed for OBD Test Pass1
1996-1999 Gasoline2 Any one3
2000 and newer Gasoline2 Evaporative system3
1998-2006 Diesel Zero
2007 and newer Diesel Particulate Filter and NMHC4

1 Implemented May 4, 2015.
2 “Gasoline” includes gasoline, propane, natural gas (CNG, LNG, LPG).
3 The misfire, fuel, and comprehensive component continuous monitors are disregarded during OBD tests on gasoline vehicles.
4 Implemented July 5, 2023.

Malfunction Indicator Lamp (MIL) Standards

The Malfunction Indicator Lamp (MIL), often referred to as the “Check Engine” light, is a critical indicator of your vehicle’s OBD system status. Here are the pass/fail standards related to the MIL during a smog check:

Condition Pass/Fail Standard
MIL illuminates when key on, engine off (KOEO) Pass MIL should light up to indicate it’s functional.
MIL turns off when engine running (KOER) Pass MIL should turn off if no active faults are detected when the engine is running.
MIL does not illuminate when key on, engine off (KOEO) Fail Indicates a potential issue with the MIL system itself.
MIL illuminates when engine running (KOER) Fail Signals an active emission-related fault.

Communication Standards

Successful communication between the inspection equipment and your vehicle’s OBD system is fundamental for a proper smog check. Failure to communicate can stem from various issues, such as a damaged OBD connector, wiring problems, aftermarket stereo installations interfering with communication, or even incorrect data responses from the vehicle’s computer.

Here are the communication standards for OBD tests:

Test Type Requirement Standard
BAR-97 Vehicle communication Vehicle must successfully communicate with the BAR-97 testing equipment.
OIS Vehicle communication & Data Transmission Vehicle must communicate with the OIS and transmit the necessary data1.

1 Required data typically includes information from OBD addresses: Mode $01 PID $00 (identifies supported data) and Mode $01 PID $01 (reports MIL status, DTCs, and monitor status).

Permanent Diagnostic Trouble Code (PDTC) Standards

Permanent Diagnostic Trouble Codes (PDTCs) are a specific type of DTC that were introduced to enhance emission control and prevent clearing of fault codes before a smog check. Unlike regular DTCs, PDTCs cannot be erased using a scan tool or by disconnecting the vehicle’s battery. They can only be cleared by the OBD II system itself once it verifies that the underlying issue has been resolved.

Since July 1, 2019, PDTC checks have been part of the BAR-OIS smog check inspection. The standards are as follows:

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

1 Some 2010 vehicles may not support PDTCs and are exempt from this check.
2 A vehicle with a stored PDTC will fail regardless of the MIL status (on or off).
3 PDTC presence is ignored if the vehicle has completed at least 15 warm-up cycles and 200 miles of driving since the last OBD data clear (as determined by Mode $01 PID $30 and $31).
4 Authorities are aware of vehicles with PDTC clearing issues and are working with manufacturers to address them. These codes will be ignored in the interim. Refer to Permanent Diagnostic Trouble Code Vehicles of Interest for more details.
5 Some manufacturers have issued extended warranties or recalls for vehicles with PDTC clearing problems. These vehicles are listed under Permanent Diagnostic Trouble Code Vehicles of Interest. Motorists with vehicles failing due to PDTCs should be directed to dealerships for potential covered repairs.

Modified Software Standards

Since July 19, 2021, smog checks also include a check for modified software. Software updates approved by the California Air Resources Board (CARB) should not cause a vehicle to fail. However, vehicles found with illegally modified software will fail the smog check. The inspection report will indicate “Modified Software” as the reason for failure. To pass, the vehicle must be restored to an OEM-approved or CARB-approved software configuration and re-tested at a licensed Smog Check station. Consumers who wish to dispute inspection results can contact the Smog Check Referee.

Vehicles of Interest: Navigating OBD Test Challenges

Certain vehicle makes and models are known to have specific issues that can affect OBD testing during smog checks. These issues range from communication problems and incomplete readiness monitors to OBD test incompatibilities and false MIL illuminations. In many cases, the inspection systems are programmed to accommodate these known anomalies. In other instances, vehicle repair may be necessary.

OIS Vehicles of Interest

The following table lists gasoline, flex-fuel (model year 2000 and newer), and diesel (model year 1998 and newer) vehicles that may encounter OBD test issues during an OIS inspection:

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 per Audi TSB #A45-15-10. Likely broken vehicle. Repair and retest.
BMW 6/1/99 – 7/31/00 323i Sedan Oxygen sensor readiness monitor issue. DME Software error. Reprogram DME with updated software. Check DME “programmed control unit” number in TSB #SI B12 16 16.
BMW 9/3/99 – 7/31/00 323iT Touring Oxygen sensor readiness monitor issue. DME Software error. Reprogram DME with updated software. Check DME “programmed control unit” number in TSB #SI B12 16 16.
BMW 6/1/99 – 7/29/00 323Ci Coupe Oxygen sensor readiness monitor issue. DME Software error. Reprogram DME with updated software. Check DME “programmed control unit” number in TSB #SI B12 16 16.
BMW 6/23/99 – 7/29/00 323 Cic Convertible Oxygen sensor readiness monitor issue. DME Software error. Reprogram DME with updated software. Check DME “programmed control unit” number in TSB #SI B12 16 16.
BMW 2000 M52 (TU) engine Oxygen sensor readiness monitor issue. DME Software error. Reprogram DME with updated software. Check DME “programmed control unit” number in TSB #SI B12 16 16.
BMW 2000 Readiness monitor failure (oxygen sensor). ECM Software error. Reflash ECM per Recall #00E-A01 (BMW bulletin #SI B 12 15 99). Vehicle reflash required. Reflash ECM per recall.
BMW built 3/98 – 7/99 323i, 323iA, 328i, 328iA Readiness monitor failure (oxygen sensor). ECM Software error. Reflash ECM per Recall #00E-A01 (BMW bulletin #SI B 12 15 99). Vehicle reflash required. Reflash ECM per recall.
BMW built 2/99 – 7/99 328iC, 328iCA, 323iC, 323iCA, 528i, 528iA, 528iT, 528iAT Readiness monitor failure (oxygen sensor). ECM Software error. Reflash ECM per Recall #00E-A01 (BMW bulletin #SI B 12 15 99). Vehicle reflash required. Reflash ECM per recall.
BMW built 9/98 – 7/99 Z3 roadster 2.3 Readiness monitor failure (oxygen sensor). ECM Software error. Reflash ECM per Recall #00E-A01 (BMW bulletin #SI B 12 15 99). Vehicle reflash required. Reflash ECM per recall.
BMW built 4/99 – 7/99 Z3 roadster coupe/ roadster 2.8 Readiness monitor failure (oxygen sensor). ECM Software error. Reflash ECM per Recall #00E-A01 (BMW bulletin #SI B 12 15 99). Vehicle reflash required. Reflash ECM per recall.
BMW 2001-2003 Z3 M Roadster/coupe with S54 engine No communication when ignition off/on. DME reprogram recall (Bulletin #SI B12 11 06). Follow OIS prompts. Connect/disconnect DAD when key off.
BMW 2000-2003 Z8 & M5 with S62 engine No communication when ignition off/on. DME reprogram recall (Bulletin #SI B12 11 06). Follow OIS prompts. Connect/disconnect DAD when key off.
BMW From series intro. up to 8/27/2004 M3 with S54 engine No communication when ignition off/on. DME reprogram recall (Bulletin #SI B12 11 06). Follow OIS prompts. Connect/disconnect DAD when key off.
BMW 2003 M3 EGR monitor failure. Thermostat issue. Likely broken vehicle. Repair and retest.
BMW 2007 328i Engine dies during OBD test, won’t restart. Keyless ignition issue. Separate key/vehicle, wait 20+ mins, restart. Test normally.
Chevrolet 1998-2005 DIESEL C/K2500 & C/K3500, G30, G3500, P30 (Federal diesel over 8,500 GVWR) Not OBD-II certified. Federal diesel vehicles over 8,500 GVWR not built to OBD-II standards. Test normally. OIS ignores incomplete continuous monitors. Use bulb check if no communication.
Chevrolet 1999-2005 3500 W35042 (box truck) (diesel) (Federal certified, GVWR 10,001 – 14,000) Not OBD II equipped. OBD not installed in federal vehicles during these years. OIS skips OBD functional test.
Chevrolet 2000-2002 S-10 (2WD), 2.2L I-4 (E85) Monitors won’t set (flex fuel models). System monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
Chevrolet 2000-2005 Suburban, Silverado, Express, Avalanche (gasoline) (Federal certified) “Unable to confirm OBD II requirements” message. Federally certified vehicles may not be OBD II certified. Check under-hood label for OBD certification. Follow OIS prompts (may require BAR-97 test).
Chevrolet 2001 Silverado / Tahoe C/K 1500 Secondary air system monitor failure. Air injection problem (check valve, vacuum line, pump, passages). Diagnose, repair, and retest.
Chevrolet 2002 Silverado C/K 2500HD (diesel) EGR monitor failure. Difficult drive cycle. OIS reprogrammed (10/13/2016) to allow incomplete monitor.
Chevrolet 2001-2002 Cavalier CNG (Mexico built) Catalyst monitor failure. Vehicle design anomaly. OIS reprogrammed (02/11/2015) to allow one incomplete monitor.
Chevrolet 2019 Express 2.8L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Particulate Matter sensor fault may not set DTC/MIL. ECM diagnostic information issue. ECM reprogram recall N232408230. Vehicle reflash required. Perform recall, then retest.
Chrysler 1999-2000 Town & Country 3.0L (built after 12/1/1998) EGR Monitor incomplete at high altitude. Reflash available (TSB 18-03-00). Vehicle reflash required. Repair per TSB, run monitors, retest.
Chrysler 2000 Town and Country 3.3L V-6 (E-85) Readiness monitors won’t set (flex fuel models). Monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
Chrysler 2003 PT Cruiser 2.4L turbo (manual trans) Catalyst monitor failure. PCM software error. Dealer PCM reprogram required (TSB #18-112-16). Lifetime emissions warranty. Vehicle reflash required. Repair per TSB and retest.
Chrysler 2010 (built before 2/20/2010) 300, Charger, Challenger 3.5L (5-spd auto) Readiness monitor failure, MIL illumination (P0456, P0452, P1115). Reflash available (Chrysler TSB #18-008-10). Vehicle reflash required. Repair per TSB and retest.
Dodge 1998-2002 Ram Truck 5.9L (Cummins diesel) (California certified) Some continuous monitors incomplete. Vehicle design anomaly. Test normally. OIS allows one incomplete continuous monitor.
Dodge 1998-2006 Ram 2500, Ram 3500 (diesel) (Federal certified, over 8,500 GVWR) Not OBD-II certified. Federal diesel vehicles over 8,500 GVWR not built to OBD-II standards. Test normally. OIS ignores incomplete continuous monitors. Use bulb check if no communication.
Dodge 1999-2000 Caravan 3.0L (built after 12/1/1998) EGR Monitor incomplete at high altitude. Reflash available (TSB 18-03-00). Vehicle reflash required. Repair per TSB, run monitors, retest.
Dodge 2003 Dakota, Durango, Ram Trucks 4.7L (California or 50-state certified) Catalyst monitor readiness “not supported”. Broken vehicle. Repair per TSB #18-032-10 (lifetime warranty). Test normally. OIS ignores unsupported monitors.
Dodge 2003 Ram Truck 5.9L (Cummins diesel) (California certified) MIL on, but check engine light off, no DTCs. Vehicle design anomaly. Recall #K01 (ECM reflash for CA certified vehicles). Test normally. OIS ignores MIL command if no DTCs. Advise motorist of Recall #K01 (CA certified).
Dodge 2003-2004 2500 4X2, Sprinter 3500 4X2 (diesel) (2003/2004 Federal certified, over 8,500 GVWR) Not OBD-II certified. Federal diesel vehicles over 8,500 GVWR not built to OBD-II standards. Test normally. OIS ignores incomplete continuous monitors. Use bulb check if no communication.
Dodge 2004-2005 (built after 12/7/2003) Ram Truck 5.9L (Cummins diesel) (California certified) Comprehensive component monitor incomplete. Vehicle design anomaly. Reflash available (TSB #18-030-10, lifetime warranty TSB #18-003-11). Test normally. OIS allows one incomplete monitor. Advise motorist of fix with lifetime warranty (TSB #18-003-11).
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) (Federal certified) 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) (California certified) Fuel System and Comprehensive Components monitors incomplete. Recall #K01 (ECM reflash for CA certified vehicles). Test normally. OIS ignores fuel and comprehensive component monitor readiness. Advise motorist of Recall #K01 (CA certified).
Dodge 2006-2007 Ram Truck 5.9L (ETC or ETH) (Federal Certified, built after 1/1/06), Cab Chassis 6.7L (ETJ) (Federal certified, built before 1/11/07) (Cummins diesel) Fuel System and Comprehensive Components monitors incomplete. TSB #18-017-10 (ECM reflash for Federal certified vehicles). Test normally. OIS ignores fuel and comprehensive component monitor readiness. Advise motorist of TSB #18-017-10 (Federal certified).
Dodge 2010 (built before 2/20/10) 300, Charger, Challenger 3.5L (5-spd auto) Evaporative monitor won’t 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) (California certified) NOx after-treatment monitor incomplete. Vehicle design anomaly. Test normally. OIS temporarily allows incomplete NOx after-treatment monitor (until manufacturer remedy).
Dodge/Ram 2014 ProMaster 2500 & 3500 High 3.0L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Vehicle design anomaly. Recalls V97 and ZC0. Vehicle reflash required. Perform recall, then retest.
Dodge/Ram 2015 ProMaster 1500, 2500, & 3500 High & Standard 3.0L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Vehicle design anomaly. Recalls V97 and ZC0. Vehicle reflash required. Perform recall, then retest.
Dodge/Ram 2016 ProMaster 2500 & 3500 High 3.0L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Vehicle design anomaly. Recall V97. Vehicle reflash required. Perform recall, then retest.
Ford 1998-2003 Truck 7.3L (diesel) Engine shut off when requesting Mode $09 data. 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) (Federal certified, over 8,500 GVWR) Not OBD-II certified. Federal diesel vehicles over 8,500 GVWR not built to OBD-II standards. Test normally. OIS ignores incomplete continuous monitors. Use bulb check if no communication.
Ford 2000-2004 F250, F350, E350, Excursion (gasoline) (Federal certified) “Unable to confirm OBD II requirements” message. Federally certified vehicles may not be OBD II certified. Check under-hood label for OBD certification. Follow OIS prompts (may require BAR-97 test).
Ford 2003 Focus Readiness monitor failure. Monitors difficult to complete. Broken Vehicle. Reflash PCM per TSB #06-7-5. Then test normally.
Ford 2004 E350 Super duty 5.4 (gas) Catalyst monitor failure. Vehicle design anomaly. Recall #15E06 (reflash ECM). Vehicle reflash required. Repair per recall and retest.
Ford 2011 Edge, Explorer 3.5L & 3.7L Readiness monitor failure. OBD-II data clearing/incorrect VIN reporting. Recall #13E04. Consult Ford Emission Recall #13E04. Ensure recall performed and monitors completed.
Ford 2013-2016 F series, Super Duty 6.7L (diesel) Exhaust Gas Sensor monitor incomplete. After DOC/DPF replacement, EGS monitor needs degreening (6,000-10,000 miles). Test normally. OIS ignores incomplete EGS monitor (certain VINs, DOC/DPF replaced after 1/1/2022). Expires 10/8/2025.
Ford 2015-2019 Transit 3.2L (diesel) Exhaust Gas Sensor monitor incomplete. After DOC/DPF replacement, EGS monitor needs degreening (6,000-10,000 miles). Test normally. OIS ignores incomplete EGS monitor (certain VINs, DOC/DPF replaced after 1/1/2022). Expires 10/8/2025.
Ford 2020-2022 Escape (all engines, gasoline & hybrid) No communication with BAR-OIS. Design issue. Software update available (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
Ford 2021-2022 Bronco Sport (all engines, gasoline not hybrid) No communication with BAR-OIS. Design issue. Software update available (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
Ford 2021-2023 E350, E450 (all engines, gasoline not hybrid) No communication with BAR-OIS. Design issue. Software update available (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
Ford 2025 and newer Explorer (2.3L) AWD, RWD (Test Group SFMXT02.34K2) No OBD communication. OBDonUDS vehicle. DAD 1.0 units incompatible. Cal-VIS skips OBD test until DAD 2.0 certified.
Freightliner 1998-2004 M Line Walk In Van (diesel) (Federal certified, GVWR 6,001-14,000) Not OBD II equipped. OBD not required in federal vehicles in this GVWR range. 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 OIS prompts “no vehicle voltage”. No power on OBDII connector (DLC pin 16). Possible blown fuse. Use auxiliary DAD cables/power supply.
GM 2015-2017 All gasoline powered Readiness monitor failure. Post catalyst oxygen sensor monitor needs 1,000 mile catalyst break-in. Bulletin #15-NA-010. Inspect after 1,000 miles or send to Referee.
GMC 1998-2005 DIESEL C/K2500 & C/K 3500, Savana G3500, Workhorse P30 Forward Cntl (Federal diesel over 8,500 GVWR) Not OBD-II certified. Federal diesel vehicles over 8,500 GVWR not built to OBD-II standards. Test normally. OIS ignores incomplete continuous monitors. Use bulb check if no communication.
GMC 1999-2005 W3500 W35042 (box truck) (diesel) (Federal certified, GVWR 10,001 – 14,000) Not OBD II equipped. OBD not required in federal vehicles in this GVWR range. OIS skips OBD functional test.
GMC 2000-2002 Sonoma (2WD), 2.2L I-4 (E85) Monitors won’t set (flex fuel models). System monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
GMC 2000-2005 Sierra, Yukon, Savana (gasoline) (Federal certified) “Unable to confirm OBD II requirements” message. Federally certified vehicles may not be OBD II certified. Check under-hood label for OBD certification. Follow OIS prompts (may require BAR-97 test).
GMC 2002 Sierra C/K 2500HD (diesel) EGR monitor failure. Difficult drive cycle. OIS reprogrammed (10/13/2016) to allow incomplete monitor.
GMC 2019 Savana 2.8L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Particulate Matter sensor fault may not set DTC/MIL. ECM diagnostic information issue. ECM reprogram recall N232408230. Vehicle reflash required. Perform recall, then retest.
GMC 2022 Sierra K2500 SLT 6.6L (diesel) (California certified) Exhaust Gas Sensor monitor incomplete. Vehicle design anomaly. Test normally. OIS temporarily allows incomplete Exhaust Gas Sensor monitor (until manufacturer remedy).
Hyundai 2002 Sonata Readiness monitor failure. Monitors difficult to complete. Drive cycle twice (TSB #02-36-030). Run drive cycle. See TSB #02-36-030.
Hyundai 2003 Tiburon No communication with generic OBD equipment. Pin 5 not grounded. Ground pin 5 to pin 4 (TSB). Recall #057, Hyundai TSB #03-01-003-01. Test normally on OIS. For generic OBD, perform recall #057 and TSB #03-01-003-01.
Infiniti 2000 -2001 I30 Catalyst monitor failure. OBD catalyst code only on OEM scan tool. Test catalyst, replace if defective.
Infiniti 2000 -2001 I30 Readiness monitor failure. Monitors difficult to complete. Run drive cycle.
Isuzu 1998-2005 NPR (diesel) (Federal certified, GVWR 10,001- – 14,000) Not OBD II equipped. OBD not required in federal vehicles in this GVWR range. OIS skips OBD functional test.
Isuzu 2000-2002 Hombre (2WD) 2.2L I-4 (E85) Monitors wont set (flex fuel models). System monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
Jaguar 2017 Jaguar XE, XF, & F-Pace 2.0L (diesel) (California certified, Test Group HJLXJ02.0STY) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall H444. Test normally. Direct to Jaguar dealer for software update if NOx monitor incomplete.
Jaguar 2018 Jaguar XE, XF, F-Pace & Rover Velar 2.0L (diesel) (California certified, Test group JJLXJ02.0STY) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall H444. Test normally. Direct to Jaguar dealer for software update if NOx monitor incomplete.
Jaguar 2019 Jaguar XE, XF, & F-Pace 2.0L (diesel) (California certified, Test group KJLXJ02.0STY) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall H444. Test normally. Direct to Jaguar dealer for software update if NOx monitor incomplete.
Jeep 2005-2006 Wrangler O2 sensor, O2 heater, catalyst readiness monitors may be not ready. Vehicle design anomaly. TSB #25-005-13 Rev. A (wiring modification). OIS allows incomplete O2 heater monitor.
Jeep 2010-2011 Wrangler 3.8L Oxygen sensor monitor failure. PCM monitor frequency issue. Recalls L34/L35, OEM drive cycle issue. TSB 18-027-10. Reflash PCM per TSB 18-027-10. Special drive cycle may be needed.
Kia 2009 Borrego LX/EX 3.8L Readiness monitor failure (EGR). EGR monitor difficult to complete/drive cycle issue. OIS reprogrammed (12/7/2017) to allow incomplete EGR/VVT monitor.
Land Rover 2017 Discovery, Range Rover, Range Rover Sport 3.0L (diesel) (California certified, Test group HJLXT03.0GTR) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall N808. Test normally. Direct to Land Rover dealer for software update if NOx monitor incomplete.
Land Rover 2018 Velar 2.0L (diesel) (California certified, Test group JJLXJ02.0STY) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall N808. Test normally. Direct to Land Rover dealer for software update if NOx monitor incomplete.
Land Rover 2019 Velar 2.0L (diesel) (California certified, Test group KJLXJ02.0STY) NOx Aftertreatment System monitor incomplete. Vehicle design anomaly. Dealer recall N808. Test normally. Direct to Land Rover dealer for software update if NOx monitor incomplete.
Lexus 2007 RX400 Hybrid Oxygen sensor (air/fuel) monitor readiness failure. AC monitor issue. Air Fuel monitor issue. Software update (Lexus campaign FLD, TSB #L-SB-0027-15). Advise motorist recall may be required if oxygen sensor monitor fails. Check recall status: toyota.com/recall.
Lincoln 2011 MKX 3.5L & 3.7L Readiness monitor failure. OBD-II data clearing/incorrect VIN reporting. Recall #13E04. Consult Ford Emission Recall #13E04. Ensure recall performed and monitors completed.
Lincoln 2020-2022 Corsair (all engines, gasoline & hybrid) No communication with BAR-OIS. Design issue. Software update available (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
Mazda 2000 MPV Catalyst monitor failure. Catalyst and/or oxygen sensor issue. Likely broken vehicle. Repair and retest.
Mazda 2002-2003 B3000 (2WD) 3.0L V-6 (E-85) Readiness monitors won’t set (flex fuel models). Monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
Mazda 2003-2004 Mazda 6 False MIL illumination, U-code DTCs during OBDII test. PCM sensitive to OBD tool connection/disconnection (ignition ON/engine running). Mazda Service Bulletin #01-002/05. Reset monitors. Connect/disconnect DAD when key off.
Mazda 2005 Mazda 6 (with 2.3 only) False MIL illumination, U-code DTCs during OBDII test. PCM sensitive to OBD tool connection/disconnection (ignition ON/engine running). Mazda Service Bulletin #01-002/05. 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 connection/disconnection (ignition ON/engine running). TSB #01-024/05. Reprogram PCM/TCM or Emission Recall TSB #1303F. Follow OIS prompts. Connect/disconnect DAD when key off.
Mitsubishi Fuso 1998-2004 FE639/FG639 (diesel) (Federal certified, GVWR 10,001 –14,000) Not OBDII equipped. OBD not required in federal vehicles in this GVWR range. OIS skips OBD functional test.
Mitsubishi 2000-2001 Montero, Montero Sport, Diamante, 3000GT Mirage, Galant, Expo/Expo LRV, Eclipse (except 2.0L non—turbo 420A engine) Readiness monitor failure. Monitors difficult to complete. Follow Mitsubishi service manual drive cycles.
Nissan 1999-2007 UD1200 (Diesel) (Federal certified, GVWR 10,001-14,000) Not OBDII equipped. OBD not required in federal vehicles in this GVWR range. OIS skips OBD functional test.
Nissan 2000-2001 Maxima Catalyst monitor failure. OBD catalyst code only on OEM scan tool. Test catalyst, replace if defective.
Nissan 2000-2006 All models Readiness monitor failure. Incomplete monitors during normal driving. Follow specific drive cycle. Follow drive cycle. See owner’s manual.
Plymouth 1999-2000 Voyager 3.0L (built after 12/1/1998) EGR Monitor incomplete at high altitude. Reflash available (TSB 18-03-00). Vehicle reflash required. Repair per TSB, run monitors, retest.
Plymouth 2000 Voyager 3.3L V-6 (E-85) Readiness monitors won’t set (flex fuel models). Monitors disabled for high ethanol blends. OIS ignores all 11 readiness monitors.
Suzuki 2001 Aerio Readiness monitor failure. Monitors difficult to complete. Follow drive cycle (OBD Clearinghouse or Suzuki service info).
Suzuki 2004 Forenza Readiness monitor failure. Monitors difficult to complete. Follow drive cycle (OBD Clearinghouse or Suzuki service info).
Toyota 2000-2006 All models Readiness monitor failure. Monitors difficult to complete. Follow Toyota service information drive cycles.
Toyota 2003-2004 4 Runner VSC light may illuminate with aftermarket scan tool (CAN protocol). Stability control calibration loss with CAN protocol. Reset zero-point calibration. OIS avoids CAN protocol on these vehicles.
Toyota 2007 Highlander Hybrid Oxygen sensor (air/fuel) monitor readiness failure. Air Fuel monitor issue. Software update (Toyota Special Service Campaign F0P, TSB #0042-15). Advise motorist recall may be required if oxygen sensor monitor fails. Check 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. Repair other failures first.
Volvo 2004-2006 S40, V50 AC readiness monitor mistakenly set to supported. Vehicle design anomaly. OIS ignores A/C monitor status.
Volvo 2005-2007 XC90 AC readiness 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 per VW TSB #45 15 01. Likely Broken Vehicle Repair and Retest.

Permanent Diagnostic Trouble Code Vehicles of Interest

Certain vehicles are known to have issues with Permanent Diagnostic Trouble Codes (PDTCs) that may affect smog check results. The following table outlines these vehicles and provides guidance for inspectors:

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 won’t 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 won’t clear. No remedy available. Test normally. BAR-OIS ignores these codes.
Chrysler 2011-2015 200; 2.4, 3.6 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Chrysler 2010-2014 300; 3.6, 5.7, 6.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Chrysler 2017 Pacifica Hybrid Fails for PDTC C2200 or B22A9-00. Reflash modules per TSB 08-005-21 and 08-006-21. Reflash then retest.
Chrysler 2018 Pacifica Hybrid Fails for PDTC C2200 or B22A9-00. Reflash modules per TSB 08-008-21 and 08-009-21. Reflash then retest.
Chrysler 2019 Pacifica Hybrid Fails for PDTC C2200 or B22A9-00. Reflash modules per TSB 08-011-21 and 08-012-21. Reflash then retest.
Chrysler 2011-2015 Town and Country; 3.6 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2014 Avenger PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2012 Caliber; 2.0, 2.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2015 Challenger; 3.6, 5.7, 6.4 Fails for PDTC U0140. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2014 Charger; 3.6, 5.7, 6.4 Fails for PDTC U0140. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2015 Grand Caravan; 3.6 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2010-2011 Dakota; 3.7, 4.7 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2013 Dart; 2.0 Fails for PDTC U0140. Reflash per Recall V50 and V51. Reflash then retest.
Dodge 2013 Dart; 2.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2014-2015 Dart; 2.0, 2.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2014 Durango; 3.6, 5.7 Fails for PDTC U0140. Reflash per Recall V51. Reflash then retest.
Dodge 2011-2015 Journey; 2.4, 3.6 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Dodge 2010-2011 Nitro; 3.7, 4.0 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Ford 2011-2014 Mustang; 3.7 & 5.0 (gasoline) Fails for PDTC P0315. Vehicle not self-clearing permanent fault code. Customer Satisfaction Program 17N01. Refer to Ford Customer Satisfaction Program 17N01.
Freightliner 2014-2015 Sprinter 2500 Sprinter 3500 (diesel) Fails for PDTCs 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 Fails for PDTC U0140. Reflash per Recall V51. Reflash then retest.
Jeep 2010 Commander; 5.7 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Jeep 2010-2015 Grand Cherokee; 3.6, 5.7, 6.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Jeep 2014-2017 Grand Cherokee (diesel) Fails for PDTC P1D30. Vehicle not self-clearing permanent fault code. Test normally. BAR-OIS ignores this code.
Jeep 2010-2012 Liberty; 3.7 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Jeep 2011-2015 Patriot / Compass; 2.0, 2.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Jeep 2010-2015 Wrangler; 3.6, 3.8 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Mercedes 2010-2013 350 Bluetec Fails for PDTCs 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) Fails for PDTCs 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 Fails for PDTC U0140. Reflash per Recall V51. Reflash then retest.
Ram 2013 1500; 3.6, 5.7 PDTCs won’t clear. Reflash per Recall V50. Reflash then retest.
Ram 2014-2017 1500 (diesel) Fails for PDTC P1D30. Vehicle not self-clearing permanent fault code. Test normally. BAR-OIS ignores this code.
Ram 2010-2015 2500; 5.7, 6.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Ram 2011-2015 3500 Cab Chassis; 5.7, 6.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Ram 2013-2015 3500 Pickup; 5.7, 6.4 PDTCs won’t clear. Reflash per Recall V51. Reflash then retest.
Ram 2014 Promaster; 3.6 PDTCs won’t clear. Reflash per Recall V50. Reflash then retest.
Volkswagen 2010 Touareg; 3.0 (TDI/diesel) PDTCs P20B5, P0087, P0088, and P053F won’t 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 won’t clear. No remedy available. Test normally. BAR-OIS ignores these codes.

BAR-97 EIS Vehicles of Interest

For older vehicles (model year 1996-1999) undergoing BAR-97 EIS inspections, certain monitor readiness issues are known. In many cases, the BAR-97 EIS system is programmed to accommodate these vehicle-specific design anomalies:

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 All monitors reset on key-off. Recall #678 (CA certified vehicles originally sold in CA). TSB #18-005-01 (lifetime warranty, federal and CA northeast). 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 All monitors reset on key-off. Recall #678 (CA certified vehicles originally sold in CA). TSB #18-005-01 (lifetime warranty, federal and CA northeast). 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 All monitors reset on 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 All monitors reset on key-off. Recall #678 (CA certified vehicles originally sold in CA). TSB #18-005-01 (lifetime warranty, federal and CA northeast). 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 (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
Ford 2021-2023 F-650, F-750 (all engines, Gasoline not hybrid) No OBD communication. Design issue. Software update available (SSM 50974). Test normally. Direct to Ford dealer for software update if no communication.
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 (TSB #ITB98-011F). Test as normal.
Kia 1996 Sephia Sportage Monitors difficult to complete. EIS ignores readiness status.
Lexus 1996-1999 All models Monitors difficult to complete. Follow Lexus service information drive cycles. Test as normal.
Mercedes-Benz 1996 C220, E320, C280, S320, SL320 MIL illuminates when scan tool connected. No trouble codes stored. OBD II connector used as RPM source during Smog Check. Do not connect OBD II until prompted for OBD II test. Use conventional 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 Mitsubishi service manual drive cycles. Test as normal.
Mitsubishi 1999 All models Some monitors difficult to complete. Follow Mitsubishi service manual 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 (Nissan TSB #NTB98-018G). Comply with TSB, then test as normal.
Nissan 1999 All models Monitors difficult to complete. Follow owner’s manual drive cycle. Test as normal.
Plymouth 1996 Breeze, Neon All monitors reset on key-off. Recall #678 (CA certified vehicles originally sold in CA). TSB #18-005-01 (lifetime warranty, federal and CA northeast). 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 (drive cycle). 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 difficult to complete. Follow Toyota service information drive cycles. 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 per VW TSB #45 15 01. Likely Broken Vehicle. Repair and retest.
Volvo 1996-1998 All models Monitors difficult to complete. Follow Service Bulletin 25-19 drive cycles. EIS ignores readiness status.

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