(1) Vehicles shall not be allowed to complete emission performance testing if one or more of the following conditions exist when the vehicle is presented for testing:
- (a) For 1975 through 1995 model gasoline powered motor vehicles, if the vehicle exhaust system leaks in such a way as to dilute the exhaust emissions being sampled by the exhaust gas analyzer, the sum of carbon monoxide and carbon dioxide concentrations recorded for idle speed reading from an exhaust outlet must not be less than 6%.
- (b) For 1975 through 2001 model diesel powered motor vehicles, if the vehicle’s exhaust system leaks in such a way as to dilute the exhaust emissions being sampled.
- (c) The visible emissions from the motor vehicle are such that it would interfere with operation of the testing equipment.
- (2) Gasoline powered motor vehicle models 1975 through 1995 which have idle speed emission values that exceed the test standards specified in Table I shall fail the emission performance test. TABLE I MAXIMUM IDLE SPEED EMISSIONS ALLOWABLE DURING IDLE SPEED EMISSIONS TEST CO (%) HC (PPM) LIGHT-DUTY LIGHT-DUTY LIGHT-DUTY LIGHT-DUTY VEHICLE VEHICLES LESS VEHICLES VEHICLES LESS VEHICLES MODEL THAN OR EQUAL GREATER THAN THAN OR EQUAL GREATER THAN YEAR TO 6000 LBS GVWR 6000 LBS GVWR TO 6000 LBS GVWR 6000 LBS GVWR 1975 5.0 6.5 500 750 1976 5.0 6.5 500 750 1977 5.0 6.5 500 750 1978 4.0 6.0 400 600 1979 4.0 6.0 400 600 1980 3.0 4.5 300 400 1981- 1.2 4.0 220 400 1995
(3) Light-duty diesel powered motor vehicle models 1975 through 2001 shall be subject to the curb idle test as follows:
- (a) A diesel vehicle shall not emit visible emissions in excess of ten (10) percent opacity for ten (10) or more consecutive seconds, as measured at idle engine speed.
- (4) All 1996 and newer gasoline powered motor vehicles and all 2002 and newer diesel powered motor vehicles shall be subject to an OBD inspection. An OBD check shall consist of two parts: a visual check of the MIL and an electronic examination of the OBD computer. The vehicle is required to pass a MIL command on test and a bulb check test. After the vehicle has passed the MIL command on test and the bulb check test, it must not have any DTCs set and all of the required readiness codes must be set in order to pass an OBD inspection.
- (5) When a motor vehicle is equipped with other than the original engine or when a motor vehicle has been constructed, modified, customized or altered in such a way so that the model year cannot be clearly determined, the vehicle shall be classified for purposes of the emission performance test by the model year of the chassis.
Authority: T.C.A. §§ 4-5-201, et seq., and 68-201-105. Administrative History: Original rule filed February 14, 1994; effective April 30, 1994. Stay of effective date filed April 15, 1994; effective June 14, 1994. Amendment filed September 19, 2001; effective December 3, 2001. Repeal and new rule filed September 28, 2004; effective December 12, 2004.