P0405 means the EGR position sensor 'A' (the primary feedback sensor on the EGR valve) is sending a voltage below the normal operating range, typically below 0.2V. This is almost always a wiring fault, a corroded connector, or a sensor that has failed shorted to ground.
P0405 means the EGR position sensor 'A' (the primary feedback sensor on the EGR valve) is sending a voltage below the normal operating range, typically below 0.2V. This is almost always a wiring fault, a corroded connector, or a sensor that has failed shorted to ground.
P0405 è un codice diagnostico di guasto relativo a emissioni, classificato con gravità moderate. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0405 e accende la spia motore.
Se il tuo veicolo ha attivato P0405, potresti notare uno o più di questi sintomi:
Ecco le cause più comuni di P0405, ordinate in base alla probabilità che siano la causa del problema:
In genere sì, per brevi tragitti. Driveable. P0405 means the EGR position sensor (sensor A) is reporting a voltage lower than the expected operating range. The ECU loses confidence in EGR position feedback and may disable the EGR system or enter limp mode. Expect rough idle and a failed emissions test.
Segui questi passaggi per individuare la causa principale di P0405:
I costi di riparazione di P0405 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:
Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.
P0405 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:
2007–2024
The N47 and B47 320d EGR position sensor sits in a heat-soaked location near the turbo, and is integrated into the EGR valve. P0405 typically appears around 120,000 km, often after the connector seal degrades and lets moisture in. INPA or ISTA can confirm the sensor voltage in the live data screen. Always reset adaptation values after valve replacement.
Costi stimati per i proprietari di BMW 3 Seriesadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici BMW
Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.
2009–2024
On EA189 and EA288 TDI Golfs, P0405 is often caused by harness chafing where the EGR loom passes near the EGR cooler. The chafed signal wire grounds against the cooler body and pulls the sensor voltage low. VCDS group 99 (EA189) or group 144 (EA288) shows the live sensor voltage. Repair the chafe with high-temp tape and replace the affected sensor wire section.
Costi stimati per i proprietari di Volkswagen Golfadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Volkswagen
Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.
2008–2024
B8 and B9 A4 2.0 TDI models share the EGR sensor failure modes with the Golf. The B8 has tighter packaging that makes the connector harder to access without removing the intake duct. On 3.0 TDI V6 (CCWA, CTBA), P0405 may indicate which bank with a suffix in the freeze frame data, but verify in VCDS first. Adaptation reset via VCDS or ODIS is required after valve replacement.
Costi stimati per i proprietari di Audi A4adeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Audi
Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.
2010–2024
OM651 Sprinter EGR position sensors fail regularly under heavy commercial use, often before 120,000 km. The Mercedes connector is exposed and prone to road salt corrosion in northern European winters. P0405 frequently appears alongside P0401 or P0404, and Star Diagnosis (XENTRY) is needed for proper adaptation reset after replacement. Aftermarket EGR valves with integrated sensors are available, but quality varies.
Costi stimati per i proprietari di Mercedes Sprinteradeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Mercedes-Benz
Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.
Questi codici compaiono spesso insieme a P0405 o indicano problemi correlati:
Short distances yes. The ECU disables EGR control when the position sensor signal is unreliable, so the engine runs without EGR (more NOx, more pinging on petrol, possible limp mode on diesel). Resolve within a couple of weeks to avoid intake carbon buildup and emissions test failure.
About 60% of the time it is the integrated sensor failing inside the EGR valve. The other 40% is wiring or connector corrosion. Always inspect the connector and measure the 5V reference at the sensor before condemning the valve, since wiring repairs are far cheaper.
On older vehicles with separate DPFE sensors (older Fords, some Japanese makes), yes. On modern BMW, Mercedes, and VAG vehicles the sensor is integrated into the EGR valve and not available separately. You replace the whole valve assembly.
Diesel EGR valves run hot and dirty. The position sensor sits directly on the valve, so it sees constant thermal cycling and soot. Hall-effect sensors degrade over time, and the connector seals fail. Failure between 100,000–150,000 km is typical on BMW N47/B47 and VW EA189/EA288.
Clean a carboned diesel EGR valve yourself for €10-30. Symptoms, step-by-step removal, when to clean vs replace, and how to verify the fix with OBD2.
EGR deletion is the hardest of the three diesel emissions cheats to detect with OBD2. Here is what the scan tool reveals, what it cannot, and three physical checks that close the gap.
Collega un adattatore OBD2 Bluetooth standard, esegui la scansione dei codici e ottieni una diagnosi basata sull'IA con livelli di gravità e stime dei costi di riparazione.
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