P0406 MAZDA Exhaust Gas Recirculation Sensor A Circuit High

Possible causes
– EGR Valve clogged, dirty or leaky
– EGR valve damaged/defective
– EGR volume control solenoid valve
– EGR temperature sensor and circuit
– EGR volume control solenoid valve harness is open or shorted
– EGR volume control solenoid valve circuit poor electrical connection
When is the obd code mean?
An improper voltage signal is sent to ECM through the valve
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Engine hesitation
P0406 MAZDA OBD Code Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control