What is an EGR Valve Position Sensor?
The EGR valve position sensor monitors the operation of the exhaust gas recirculation valve for the powertrain control module (PCM). This allows the PCM to constantly map the position of the EGR valve, and make fine adjustments to optimize vehicle and emission control system performance.
How do EGR Valve Position Sensors work?
The PCM will send reference voltage to the EGR valve position sensor, and, in return, it expects the EGR valve position sensor to relay back an altered voltage. The altered voltage, or signal voltage, will be translated by the PCM as the exact position of the EGR valve in its regular path of travel. In other words, it will tell the PCM to what extent the EGR valve is opened or closed. This allows for the PCM to self-check the EGR system for proper operation, and to acknowledge when and to what degree the EGR valve should be opened or closed.
What are the symptoms of a bad EGR Valve Position Sensor?
If the EGR valve position sensor fails, at the very least the check engine light will be illuminated. This will indicate that there are fault codes pertaining to an emission system component failure stored in the PCM. If the position sensor reads correctly, but within its normal range, the engine may run roughly, stall at idle, misfire, or hesitate to accelerate under normal conditions.Fuel mileage will likely suffer as well.
Can I drive with a bad EGR Valve Position Sensor?
Anytime the check engine light comes on, especially if flashing, the vehicle should be seen by a professional, or, at the very least, scanned to identify the on-board diagnostic trouble codes stored in the engine control module. The check engine light should not be ignored, especially if the issue pertains to the EGR system. Not only will a faulty EGR system lead to poor gas mileage and the mentioned symptoms, but it can ultimately lead to failure of the vehicle to start and run. Having the vehicle serviced sooner, rather than later, is in the best interest of the owner and vehicle.