Exhaust Emission System - N16: Notes

The N12/N16 4-cylinder gasoline engine satisfies the EURO 4 exhaust emission standards, or LEVII in the US version (LEV = Low Emission Vehicle). The engine has a catalytic converter close to the engine. On the US version there is an additional catalytic converter on the underbody. Two oxygen sensors are used for oxygen level control. A broadband oxygen sensor (Bosch: 4.9 universal oxygen sensor) acts as the control sensor upstream of the catalytic converter close to the engine. A bistable sensor (NTK: FLO type) serves as the monitoring sensor downstream of the catalytic converter.