OBD-II Code P0405 is defined as a Exhaust Gas Recirculation Sensor A Circuit Low. NOx gases, which are a leading cause of acid rain and in some people, respiratory problems, are formed when the engine combustion temperatures become too high (2500° F).Click to see full answer. In this regard, what is a exhaust gas recirculation sensor?The exhaust gas recirculation (EGR) system is designed to lower combustion temperatures and reduce oxides of nitrogen emissions (NOx). The typical symptoms of a failed EGR temperature sensor include pinging, increased emissions and an illuminated Check Engine Light.Similarly, what is exhaust gas recirculation control circuit? P0403 is an OBD-II generic code that indicates that the engine control module (ECM) has detected the engine exhaust gas recirculation (EGR) circuit has malfunctioned. The ECM detected a short or open circuit in the EGR vacuum control solenoid or wiring to the solenoid. Likewise, how do I fix code p0405? Replacing the EGR position sensor after the wiring is checked to be okay. Repairing the wiring short to the EGR position sensor or connector signal return. Repairing an open in the voltage reference to the EGR sensor. What causes p0400 code?Code P0400 is triggered when the EGR temperature sensor does not see a temperature change when the EGR is commanded to open. These sensors tend to get a lot of carbon buildup that causes them to lose sensitivity to the heat from the EGR gases.