1. A. Most 1973 and later model vehicles are equipped with an exhaust gas recirculation system to recirculate proper amounts of exhaust gases into the air/fuel mixture in the intake manifold. This recirculation into the manifold reduces combustion temperatures, thus reducing oxides of nitrogen (NOx). There are several types of EGR systems: a back pressure system which operates in conjunction with exhaust back pressure, a conventional system which operates on carburetor venturi vacuum, an electronically controlled system which operates from the engine computerized emissions control system, or a floor jet system which operates through jets in the floor of the intake manifold.

   Procedures:	Reject Vehicle If:
   (1) Inspect for presence of exhaust gas recirculation system.	(1) Exhaust gas recirculation system is required and any part is missing.
   (2) Inspect for condition of exhaust gas recirculation system.	(2) Hoses, pipes, tubing, valves, or jets are damaged, disconnected, plugged, cracked, leaking, or improperly connected.

Authority: Transportation Article, §§12-104(b) and 23-104, Annotated Code of Maryland

Effective date: April 1, 1991 (18:6 Md. R. 686)