P0409 — Exhaust Gas Recirculation Sensor A Circuit
| Meaning | The engine computer has detected a problem with the electrical circuit for the exhaust gas recirculation sensor. This sensor lets the computer know the position of the valve that recycles exhaust gases back into the engine to reduce emissions. When this circuit fails, the computer stops getting accurate feedback about the valve's actual movement. |
| Family | Powertrain (P) |
Typical symptoms
Rough idling when the engine is warm
Engine hesitation during acceleration
Common causes
Faulty EGR sensor or stuck EGR valve
Internal issue within the engine control module
What to do
Frequently asked questions
What does code P0409 mean?
Exhaust Gas Recirculation Sensor A Circuit. The engine computer has detected a problem with the electrical circuit for the exhaust gas recirculation sensor. This sensor lets the computer know the position of the valve that recycles exhaust gases back into the engine to reduce emissions. When this circuit fails, the computer stops getting accurate feedback about the valve's actual movement.
Can I keep driving with code P0409 active?
Yes, no known limitation
Common causes — P0409
Wiring or connector damage in the sensor harness Faulty EGR sensor or stuck EGR valve Internal issue within the engine control module
How do you fix code P0409?
Have a mechanic check the wiring harness and electrical connector attached to the EGR valve for corrosion or breakage first. It is best to address this soon to prevent soot buildup in the intake system.
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Contact usRelated codes
- P0400 — Exhaust Gas Recirculation Flow Malfunction
- P0401 — EGR: insufficient recirculation flow
- P0402 — EGR: excessive recirculation flow
- P0403 — EGR control circuit
- P0404 — EGR: control circuit range/performance
- P0405 — Exhaust Gas Recirculation Sensor A Circuit Low
- P0406 — Exhaust Gas Recirculation Sensor A Circuit High
- P0407 — Exhaust Gas Recirculation Sensor B Circuit Low
- P0408 — Exhaust Gas Recirculation Sensor B Circuit High
- P040B — EXHAUST GAS RECIRCULATION TEMPERATURE SENSOR 1 CIRCUIT PERFO...
- P040C — EXHAUST GAS RECIRCULATION TEMPERATURE SENSOR 1 CIRCUIT LOW
- P040D — EXHAUST GAS RECIRCULATION TEMPERATURE SENSOR 1 CIRCUIT HIGH