DTC code
P0406
EGR Sensor A Circuit High
Technical guide
Symptoms
- Illuminated check engine light
- failed emission test due to increased NOx emissions
- engine pinging
- poor fuel economy
- engine stalling
Probable causes
- Faulty EGR valve position sensor
- bad EGR valve
- circuit issues such as damaged wires or poor connections
- an issue with the PCM such as software in need of an update
Diagnostic steps
- Diagnose first — pinpoint the underlying cause of the issue.
- Consult a vehicle-specific factory repair subscription (such as ALLDATA) to determine the correct repair procedure.
- Replace EGR valve position sensor, EGR valve, or repair wiring as indicated by diagnosis.
Cross-checked technical synthesis (QA). It does not replace the manufacturer's procedure.
AI here is a librarian: this page shows only what mechanics confirmed, or says “unknown”. It never suggests a diagnosis — MECCANIC interprets the code, never your car.
0 confirmed cases on P0406
Nothing confirmed yet for this code. No guess is offered on purpose.
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