DTC P0401: Exhaust Gas Recirculation Flow Insufficient Detected [08/2013 - ]: Description
WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
Based on the driving conditions, the ECM regulates the volume of exhaust gas that is recirculated to the engine's combustion chambers and thus lowers the combustion temperature to reduce NOx emissions. The ECM monitors signals such as engine speed, coolant temperature, electric load, and vehicle speed. When the EGR permission conditions are fulfilled, the ECM controls the opening of the EGR valve linearly through signals to the EGR step motor.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0401 | Change in intake manifold pressure is small when the EGR valve is opened and closed during idle fuel cut operation (2 trip detection logic). |
|