The P0405 code on your 2022 Toyota RAV4 indicates the ECM is receiving a lower-than-expected voltage from the EGR position sensor circuit. This sensor tells the ECM where the EGR valve is positioned.
EGR Position Sensor Function
The position sensor, typically a potentiometer or Hall effect sensor, reports EGR valve position to the ECM. This feedback allows the ECM to verify the valve reaches commanded positions. The sensor outputs voltage proportional to valve position—low voltage typically indicates closed or near-closed positions.
Why Voltage Reads Low
A low circuit reading suggests the signal wire is shorted to ground, the sensor has failed in a low-output state, connector corrosion is creating a partial ground path, or the sensor is receiving insufficient reference voltage. Internal sensor wear can also cause erratic low readings.
RAV4 Diagnostic Steps
The 2022 RAV4 uses either the 2.5L Dynamic Force four-cylinder or the 2.5L hybrid system. Use Toyota Techstream to read actual sensor voltage. With ignition on and engine off, the voltage should vary as the valve moves (manually or commanded). Check for shorts to ground in the signal wire. Verify 5V reference voltage reaches the sensor.
Repair Solutions
If the sensor is shorted internally, EGR valve replacement is usually required (sensor often integrated). For wiring shorts, locate and repair the damaged section. Clean corroded connectors and verify proper pin contact. After repair, verify sensor output varies correctly with valve position.