State Test Standards

Some states have established standards for testing used vehicles to see if they are still running clean. Generally speaking, these standards are given in CO% and HC ppm. They can be checked with an exhaust gas analyzer. Typical standards for newer cars would be less than 2.0% CO (non-catalyst) or 0.5% CO (with catalyst) and less than 200 ppm of HC. If vehicle emissions are below these levels, the vehicle passes inspection. The important thing to remember is that these specifications are NOT to be used for TUNING. They are only for testing to see if the vehicle is functioning properly. If it isn't, it must be tuned using the manufacturer's procedures and specifications, then tested again.

Test standards change each year and vary from state to state, and even by county within each state. It is not possible to provide an accurate and up-to-date list in this manual. Specifications can be obtained from your local county or state government. Remember that these standards are ONLY for test purposes. The manufacturer's adjustment procedures and specifications MUST be used when actually tuning a vehicle.