The P0407 code on your 2020 Ford Explorer indicates a low voltage condition in the EGR position sensor B circuit. The presence of a 'sensor B' indicates a dual-sensor system for redundancy or different measurement purposes.
Dual EGR Sensor Systems
Some vehicles use two EGR sensors for cross-reference and improved accuracy. Sensor A and sensor B may measure position differently or serve as backup for each other. P0407 specifically identifies an issue with the secondary (B) sensor circuit.
Explorer Engine Options
The 2020 Explorer offers the 2.3L EcoBoost four-cylinder, 3.0L EcoBoost V6, and 3.3L hybrid V6. Each may have different EGR system configurations. The advanced emissions systems on these modern engines may use multiple sensors for precise control.
Low Circuit Analysis
Low voltage from sensor B suggests a short to ground in that specific circuit, sensor B failure with low output, or connector issues affecting only sensor B. Since this is independent of sensor A, the fault is isolated to the B circuit.
Diagnostic Steps
Use Ford IDS to read both sensor A and sensor B values. Compare their outputs—they should track together during valve movement. Isolate sensor B circuit and test for shorts to ground. Check the sensor B connector independently. If integrated in the valve, full valve replacement may be needed.