Exhaust Gas Recirculation: Description and Operation

EGR System Outline

System Diagram:

- The EGR system controls the oxides of nitrogen (NOx) emissions.
- Small amounts of exhaust gases are recirculated to the combustion chamber. The combustion chamber temperature is reduced and NOx emissions are lowered.
- The EGR control is enabled when the vehicle is running after warm up.

- The EGR control is cancelled when any of the following conditions are met.
- Engine is idling.
- During engine warm-up.
- Vehicle speed is below 3 km/h {2 mph}.
- Engine speed is below 1,000 rpm.
- Torque reduction control is activated. [KL engine only]
- Malfunction of ECT sensor, TP sensor, MAF sensor or EGR valve.

Block Diagram:

EGR System Monitor Outline
- The circuits of the EGR system devices are continuously monitored by the PCM.
- The EGR flow is monitored using the EGR boost sensor signal.