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DAD OIS Smog Test System

2000 model year and newer vehicles (except for vehicles 14,000 GVWR or greater) no longer require the tailpipe portion of the smog inspection.

Late model vehicles (along with diesel vehicles, 1998 & newer and which are 14,000 GVWR or under) will be administered the new On-Board Diagnostic (OBD) Inspection System (OIS) instead of having their exhaust emission analyzed while being driven on a dynamometer. The existing visual and functional test portions of the smog inspection will still apply.

The OIS will be administered using a Data Acquisition Device (DAD). The DAD will be a stand-alone test module (connected to PC) which will determine whether a vehicle passes or fails the smog check based on the data it retrieves from the vehicle's emission control computer. The DAD will be connected to a vehicle via OBD II Data Link Connector (DLC) found on all 1996 and newer OBD II compliant vehicles.

The implementation of AB 2289 is expected to reduce the time and cost of the smog check. The program will now take better advantage of a vehicle's OBD II technology by eliminating tailpipe testing and instead using the vehicle's own OBD II emissions monitoring system.

Who can smog test 2000 & newer cars?

Non-STAR smog stations will be required to purchase OIS equipment only if they choose to inspect 2000 and newer vehicles. If you own a late model car, truck, van or SUV, and you choose to visit a non-STAR certified smog station, call in advance and verify they have OIS test equipment.

You may also choose to visit any STAR station. STAR certified smog centers are required to purchase new OIS equipment. The STAR program allows participating smog stations to inspect all vehicles, but in turn requires participants be fully equipped to inspect any vehicle which comes in.

This new smog test system is already in place in 22 other states.

"This new and improved program will have the same result as taking 800,000 old cars off the road, also resulting in a more cost effective program for California motorists." said ARB Chairman, Mary D. Nichols.

California's smog check procedure requires all 1999 & older vehicles undergo a tailpipe emissions inspection to measure harmful pollutant output from the tailpipe, a visual inspection for present and properly installed emissions components, a functional test to ensure the proper operation of various emission components; and as part of the functional test, an OBD II computer diagnostic check.

Which Type Should I Choose?


Under AB 2289, the tailpipe emissions portion of the smog inspection is now eliminated for 2000 model and newer cars, trucks, vans, and SUVs.

Background on the OBD II system - All vehicles imported into the United States as of 1996 have had to be equipped with an On Board Diagnostics system referred to as OBD II. The OBD II diagnostic system is designed to monitor all aspects of your engine's emission conditions and report this information to a central database within it's computer. This information is processed and checked against the computers pre-determined values for various input levels and performance patterns.

If any problems are found, the computer will determine whether to alert the driver or not. If a decision has been made to alert the driver of an emissions problem, the "Check Engine" or "Engine Malfunction" light will illuminate on the vehicle's dashboard. In more serious emission conditions the computer may even begin to rapidly flash the "Check Engine/Malfunction" light indicating to the driver, that the vehicle needs immediate diagnosis/repair attention.

AB 2289 now requires the smog test inspection to rely on data from a vehicle's own on board emissions computer to determine the vehicle's harmful emissions production as opposed to using a smog machine to sample the vehicle's emissions output from the tailpipe. This design is expected to reduce the cost of equipment at the smog station, reduce the amount of time it takes to smog check a vehicle, and reduce the cost of the smog inspection to the consumer.

AB 2289 - Makes changes to the following smog inspection procedures and guidelines:

A. Authorize the use of On Board Diagnostic II testing to expedite the process.

B. Vehicles known to release large amounts of pollution must test at stations with the highest performance ratings.

C. Stricter fines structure for improper inspections.

D. Permit the state to contract with the private sector to manage franchise-like networks of independently owned Smog Check stations.

E. Encourage community colleges and other training institutions to develop technician-training programs.