P0406 means the EGR position sensor 'A' is sending a voltage above its normal operating range, typically above 4.5V. This is usually caused by an open signal wire, a sensor shorted to its 5V reference internally, or a sensor that has failed in the open position.
P0406 means the EGR position sensor 'A' is sending a voltage above its normal operating range, typically above 4.5V. This is usually caused by an open signal wire, a sensor shorted to its 5V reference internally, or a sensor that has failed in the open position.
P0406 è un codice diagnostico di guasto relativo a emissioni, classificato con gravità moderate. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0406 e accende la spia motore.
Se il tuo veicolo ha attivato P0406, potresti notare uno o più di questi sintomi:
Ecco le cause più comuni di P0406, ordinate in base alla probabilità che siano la causa del problema:
In genere sì, per brevi tragitti. Driveable. P0406 means the EGR position sensor (sensor A) is reporting a voltage higher than the expected range. The ECU loses trust in the EGR feedback and disables the system, causing rough idle and possible limp mode on diesels. Failed emissions test is guaranteed.
Segui questi passaggi per individuare la causa principale di P0406:
I costi di riparazione di P0406 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.
P0406 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 sensor fails high (P0406) less often than low (P0405), but when it does it usually means the integrated sensor has failed internally rather than a wiring issue. The EGR connector is buried under the intake manifold support, requiring partial disassembly for inspection. ISTA or Carly adaptation reset is mandatory after valve replacement on the B47.
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
EA189 and EA288 TDI Golfs occasionally throw P0406 after harness work or accessory installation that disturbs the EGR connector. Always check that the connector is fully clicked in before replacing parts. On EA288 (2014+), the connector lock tab can crack from age, allowing the connector to back out under engine vibration. VCDS measured value block confirms the sensor voltage.
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 suffer the same P0406 failure modes as the Golf, plus restricted access due to the larger intake manifold. On 3.0 TDI V6 models, P0406 may apply to either bank, so always read the freeze frame to confirm which side. Adaptation reset via VCDS or ODIS is required after sensor or valve service.
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 sensor open-circuit failures are less common than shorts (P0405), but when they appear they often correlate with a recent winter where road salt damaged the connector pins. Repair attempts at the harness rarely last, so most workshops fit a new pigtail connector with heat-shrink seals and a fresh EGR valve. XENTRY adaptation reset is mandatory.
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 P0406 o indicano problemi correlati:
P0405 means the signal is too low (below ~0.2V), usually a short to ground or failed sensor. P0406 means the signal is too high (above ~4.5V), usually an open wire, missing ground, or sensor failed open. Diagnostic steps are similar but the failure modes are opposite.
Yes, short distances. The ECU disables EGR control, so the engine runs without EGR. Expect rough idle and possible limp mode on diesels. Long-term driving accelerates intake carbon buildup, especially on direct-injection engines. Plan the repair within a few weeks.
No. EGR delete is illegal across the EU and UK, raises NOx emissions above legal limits, and fails periodic technical inspection (TÜV, ITV, TA, SKP). It can also void insurance and prevent vehicle registration transfer. Always repair the sensor or valve properly.
Two common reasons. First, EGR adaptation values were not reset after the new valve was fitted (required on BMW, Mercedes, VAG). Second, the carbon buildup that caused the original sensor stress is still present and damages the new sensor within months. Always clean the intake passages alongside any valve replacement.
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.
Scarica Skanyx