P0406
Exhaust Gas Recirculation Sensor A Circuit High
Generic code
Auxiliary Emissions Control
Medium severity
Moderate repair
Free on OBD DashX
Want real-world data on P0406?
See which problems come with P0406, how often it shows up in other vehicles, and how to fix it — step by step.
- Real-world fix data
- How often it happens
- Step-by-step repairs
What P0406 means
- The fault code P0406 indicates that there is an issue with the Exhaust Gas Recirculation (EGR) system. This code specifically refers to a high voltage reading in the EGR sensor circuit.
Possible symptoms
- Illuminated check engine light
- Decreased fuel economy
- Rough idling or stalling
- Engine knocking or pinging
- Failed emissions test
Possible causes
- Faulty EGR sensor
- Wiring issues in the EGR sensor circuit
- Corrosion or loose connections in the EGR sensor circuit
- Failed Engine Control Module (ECM)
Related parts
- Exhaust Gas Recirculation (EGR) Sensor: Exhaust gas recirculation (EGR) is an emissions reduction technique used in petrol and diesel engines. Problems lead to harmful emissions out of limit
Possible solutions
- Replace the faulty EGR sensor
- Check and repair any damaged wiring or connections
- Clean or tighten any corroded or loose connections
- Replace the Engine Control Module (ECM) if necessary
Free on OBD DashX
P0406 on OBD DashX
Real-world causes, how often this code shows up, and the fix — step by step.
Open P0406 No sign-up needed · available in 10 languagesScan your own car
Read and clear fault codes, live data and service resets with the CaRPM app.