Four-cylinder and 3.3L V6 models are equipped with an Exhaust Gas Recirculation (EGR) system designed to reduce NOx emissions by recirculating a portion of exhaust gases into the intake manifold. This mixture lowers combustion temperatures, decreasing the formation of NOx compounds. The EGR system includes components such as the EGR valve, EGR control solenoid valve, EGR temperature sensor, and EGR control backpressure transducer valve. The PCM controls the system, operating the EGR control solenoid using vacuum signals. The vacuum system utilizes a tap in the air intake system, while the ported vacuum control system uses a tap in the throttle body exposed to manifold vacuum during acceleration. The backpressure transducer valve monitors exhaust backpressure, aiding EGR vacuum signal control, and the EGR temperature sensor informs the PCM of temperature changes in the EGR passage. To ensure proper system function, check hoses, connections, and inspect for damage, cracks, or leaks. To test the EGR system, bring the engine to operating temperature, allowing it to idle, then open and close the throttle to observe EGR valve stem movement; movement indicates proper system function. If the stem does not move, check the vacuum signal and connections. Component checks include testing the EGR valve's diaphragm movement, vacuum retention, and rough idling with the valve open; clogged passages may necessitate cleaning. Additionally, inspect the EGR control solenoid for vacuum signals, voltage, and operation, replacing it if necessary. The EGR control backpressure transducer valve should leak when subjected to vacuum and stop when pressure exceeds 0.145 psi. Lastly, the EGR temperature sensor can be tested by submerging its tip in hot water and monitoring resistance changes. Resistance should decrease as temperature rises. Component replacement involves removing and cleaning the EGR valve and mounting surfaces, removing deposits, and ensuring proper installation. For the EGR control solenoid, unplug electrical connectors, detach vacuum hoses, and remove the solenoid before reinstalling it. For the EGR temperature sensor, disconnect the electrical connector and unscrew the sensor before applying anti-seize to the threads and reinstalling it.
Posted by NissanPartsDeal Specialist