California Statewide OBD Smog Check Inspection System (BAR-OIS) Implementation

On-Board Diagnostics (OBD II) is a vehicle computer system that monitors the performance of the emissions control system. It continuously checks critical components and reports problems that could increase vehicle emissions.

OBD II systems include built-in self-diagnostic and reporting functions. When the system detects a malfunction, it alerts the driver by turning on the check engine light (malfunction indicator light or MIL). The system also stores diagnostic trouble codes (DTCs), which help technicians quickly identify and repair the issue.

Most 1996 and newer vehicles under 14,000 lbs. GVWR, including passenger cars, pickup trucks, and SUVs, are equipped with an OBD II system.

Your vehicle’s OBD II system monitors the performance of the emission control system and alerts you when a problem could increase air pollution. When the system detects an issue, it turns on the check engine light, also known as the malfunction indicator light (MIL), on the dashboard.

The OBD II system also stores important diagnostic information about emission-related problems. This data helps technicians quickly identify and repair faults. Early diagnosis and timely repairs improve air quality, enhance fuel economy, and help prevent costly repairs in the future.

If your vehicle is 1996 or newer, it is equipped with an OBD II system and must receive an OBD II check as part of the official smog check inspection. This inspection includes a visual inspection, functional inspection, and, for some vehicles, a tailpipe inspection.

If your vehicle is 2000 or newer, it only receives an OBD II test (BAR-OIS) along with a visual inspection. Tailpipe inspections do not apply to 2000 and newer vehicles.

A vehicle may fail the BAR-OIS inspection for several common reasons, including the following:

• The check engine light is on or flashing.
  The OBD II system turns this light on when it detects a fault in the emissions control system. In most cases, diagnostic trouble codes (DTCs) accompany an illuminated check engine light.

• The check engine light does not turn on during the bulb check.
  When the key is in the ON position and the engine is off, the light must turn on briefly to confirm it works. If it does not illuminate, the vehicle will fail.

• One or more readiness monitors are not complete.
  This means the vehicle has not finished all required self-diagnostic checks. To pass, all emissions monitors must show as “ready,” confirming the onboard computer has checked each system and found no problems.

• The vehicle cannot communicate with the OBD inspection equipment.
  This issue often results from wiring problems, a damaged under-dash OBD connector, or certain vehicle design defects.

• The OBD data does not match the vehicle being tested.
  This can occur if the inspection connects to the wrong vehicle or if the OBD system has been altered or tampered with.