What P0401 means
Exhaust Gas Recirculation Flow Insufficient Detected
Common causes (general)
Before spending money on parts, verify the code with a scan tool and read freeze frame data. Freeze frame captures every sensor value at the moment the code set — this is often enough to figure out the root cause without further testing.
Manufacturer-specific descriptions
Different manufacturers use this code for slightly different failure modes. Here's what your specific make means by P0401:
| AUDI | Restriction in the EGR passages usually caused by carbon buildup, The EGR Valve is defective, Lack of proper vacuum or electrical signal to the EGR valve, Malfunctioning EGR Vacuum supply solenoid, Lack of proper EGR system feedback to the computer from the: Manifold Absolute Pressure Sensor (MAP), Differential EGR Pressure Feedback Sensor (DPFE), EGR Valve Position Sensor (EVP), EGR Temperature S... |
| BMW | Exhaust Gas Recirculation Flow Insufficient Detected |
| FIAT | EGR air control negative drift - high air quantity, |
| FORD | EGR Flow Insufficient Detected |
| HONDA | Exhaust Gas Recirculation (EGR) Insufficient Flow |
| MITSUBISHI | Exhaust Gas Recirculation Flow Insufficient Detected; EGR flow insufficient |
| NISSAN | Exhaust Gas Recirculation Flow Insufficient Detected |
| VOLKSWAGEN | Exhaust Gas Recirculation (EGR) Flow Insufficient |
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