What is the reason why the signal output voltage of EGR sensor is too low?

Generally, it should be about 0.8V to1.2v. If it is less than 0.2V, it may be that the EGR valve position sensor is loose and can be clamped again.

1, EGR (exhaust gas recirculation): The engine control computer, namely ECU, controls the solenoid valve to open in time according to the engine speed, load (throttle opening), temperature, intake air flow and exhaust temperature. The vacuum degree of the intake pipe enters the vacuum diaphragm chamber of the EGR valve through the solenoid valve, and the diaphragm lever opens the EGR valve. A small amount of exhaust gas enters the intake system through EGR valve, and enters the cylinder to participate in combustion after mixing with mixed gas.

2.EGR valve controls the amount of exhaust gas flowing back from the exhaust manifold to the intake manifold through three metering holes with increasing diameters, thus producing seven different air flow combinations. Each metering hole consists of 1 solenoid valve and needle valve. When the solenoid valve is energized, the armature is attracted upward by the magnet to open the metering hole. The characteristics of rotary needle valve ensure a good seal when EGR valve is closed.