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DTC/P0407

P0407: Exhaust Gas Recirculation Sensor "B" Circuit Low

Quick Answer
Moderata GravitàSicuro da guidare (a breve termine)Emissioni

P0407 means the EGR position sensor 'B' is sending a voltage below the normal operating range. Sensor B exists on engines with dual EGR valves (V6 and V8 diesels) or on petrol engines that use a primary and secondary feedback sensor. The fault is almost always wiring or a failed sensor shorted to ground.

Costo di riparazione stimatoDa €70 a €730+, varia in base al veicolo

Cosa significa P0407?

P0407 means the EGR position sensor 'B' is sending a voltage below the normal operating range. Sensor B exists on engines with dual EGR valves (V6 and V8 diesels) or on petrol engines that use a primary and secondary feedback sensor. The fault is almost always wiring or a failed sensor shorted to ground.

P0407 è un codice diagnostico di guasto relativo a emissioni, classificato con gravità moderate. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0407 e accende la spia motore.

Quali sono i sintomi di P0407?

Se il tuo veicolo ha attivato P0407, potresti notare uno o più di questi sintomi:

  • Check engine light illuminated
  • Rough idle, sometimes uneven cylinder firing on V6/V8 diesels
  • Reduced power, possible limp mode on diesels
  • Hesitation during acceleration
  • Failed emissions or periodic technical inspection

Cosa causa P0407?

Ecco le cause più comuni di P0407, ordinate in base alla probabilità che siano la causa del problema:

altaEGR position sensor B shorted to ground internally
altaDamaged signal wire from sensor B grounding against engine components
mediaCorroded sensor B connector pulling signal low
mediaOpen 5V reference to sensor B (less common, often affects both sensors)
bassaFailed ECU driver for sensor B circuit (rare)

È sicuro guidare con P0407?

In genere sì, per brevi tragitti. Driveable. P0407 affects the second EGR position sensor (sensor B), present on engines with dual EGR valves or dual feedback sensors. The ECU loses confidence in EGR position feedback and may disable EGR or enter limp mode on diesels. Failed emissions test is guaranteed.

Come si diagnostica P0407?

Segui questi passaggi per individuare la causa principale di P0407:

  1. Identify which physical sensor is sensor B (workshop manual). On V6/V8 diesels, this is usually the bank opposite to sensor A
  2. Back-probe the sensor B signal wire. A healthy sensor at rest reads 0.5–1.0V. Below 0.2V indicates short to ground
  3. Verify 5V reference and ground at sensor B connector. If 5V reference is missing, check whether sensor A is also affected
  4. Inspect the harness branch for sensor B for chafing against the EGR cooler or exhaust manifold heat shield
  5. Replace sensor B (or the integrated valve assembly) if wiring tests good and signal reads steadily low

Quanto costa riparare P0407?

I costi di riparazione di P0407 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and repair sensor B connector €10–€60 €60–€180 €70–€240 Moderata
Replace EGR valve B (sensor integrated) €150–€450 €100–€280 €250–€730 Moderata
Repair EGR wiring harness (sensor B branch) €20–€120 €120–€350 €140–€470 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

P0407 su veicoli specifici

P0407 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:

BMW

P0407 su BMW 3 Series

2014–2024

P0407 on a 3 Series typically appears on the 330d and 335d with B57 inline-6 diesel, which uses two EGR feedback sensors (high-pressure and low-pressure EGR). Sensor B is usually the low-pressure EGR position. The harness for the low-pressure sensor routes near the rear of the engine and is prone to chafing where it crosses the transmission tunnel. ISTA is required for adaptation reset.

Cosa causa P0407 su una BMW 3 Series?

BMW 3 SeriesB57 low-pressure EGR sensor B short from harness chafing at transmission tunnel
BMW 3 SeriesDual high/low pressure EGR system, both feedback sensors must work

Costo di riparazione di P0407 per BMW 3 Series

Costi stimati per i proprietari di BMW 3 Seriesadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici BMW

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and repair sensor B connector €14–€84 €84–€252 €98–€336 Moderata
Replace EGR valve B (sensor integrated) €210–€630 €140–€392 €350–€1022 Moderata
Repair EGR wiring harness (sensor B branch) €28–€168 €168–€490 €196–€658 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Volkswagen

P0407 su Volkswagen Golf

2012–2024

P0407 is uncommon on Golf TDIs because most 4-cylinder EA189/EA288 engines only have a single EGR position sensor. When it appears, it usually means the freeze frame labels the sole position sensor as 'B' in a market-specific calibration, or the vehicle has the rare high/low-pressure EGR variant fitted to some commercial Caddy and Crafter derivatives. VCDS confirms which sensor is at fault.

Cosa causa P0407 su una Volkswagen Golf?

Volkswagen GolfRare high/low-pressure EGR variant on commercial Crafter/Caddy derivatives
Volkswagen GolfMarket-specific calibration labeling the single position sensor as 'B'

Costo di riparazione di P0407 per Volkswagen Golf

Costi stimati per i proprietari di Volkswagen Golfadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Volkswagen

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and repair sensor B connector €12–€69 €69–€207 €81–€276 Moderata
Replace EGR valve B (sensor integrated) €173–€518 €115–€322 €288–€839 Moderata
Repair EGR wiring harness (sensor B branch) €23–€138 €138–€402 €161–€541 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Audi

P0407 su Audi A4

2010–2024

P0407 is most common on the A4 3.0 TDI V6 (CCWA, CTBA, CAPA codes), which uses two EGR valves with two position sensors. Sensor B is the bank-2 EGR position. The harness for bank 2 routes behind the engine and is hard to access. Many shops replace both EGR valves together on high-mileage 3.0 TDI cars to avoid a repeat job. VCDS or ODIS adaptation reset for both banks is mandatory.

Cosa causa P0407 su una Audi A4?

Audi A43.0 TDI V6 bank-2 EGR position sensor failure (sensor B)
Audi A4Both EGR valves usually replaced together on high-mileage cars

Costo di riparazione di P0407 per Audi A4

Costi stimati per i proprietari di Audi A4adeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Audi

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and repair sensor B connector €13–€75 €75–€225 €88–€300 Moderata
Replace EGR valve B (sensor integrated) €188–€563 €125–€350 €313–€913 Moderata
Repair EGR wiring harness (sensor B branch) €25–€150 €150–€438 €175–€588 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Mercedes-Benz

P0407 su Mercedes Sprinter

2014–2024

OM642 V6 diesel Sprinters (3.0 CDI) use dual EGR valves with dual sensors. P0407 indicates the bank-2 (left bank) position sensor is reading low. OM651 4-cylinder Sprinters do not typically have a sensor B, so P0407 on an OM651 usually points to a wiring labeling issue. XENTRY required for proper adaptation reset on V6 OM642 after sensor or valve service.

Cosa causa P0407 su una Mercedes Sprinter?

Mercedes SprinterOM642 V6 bank-2 EGR sensor B short to ground
Mercedes SprinterOM651 4-cylinder: P0407 usually indicates wiring or naming issue, not sensor B

Costo di riparazione di P0407 per Mercedes Sprinter

Costi stimati per i proprietari di Mercedes Sprinteradeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Mercedes-Benz

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and repair sensor B connector €13–€78 €78–€234 €91–€312 Moderata
Replace EGR valve B (sensor integrated) €195–€585 €130–€364 €325–€949 Moderata
Repair EGR wiring harness (sensor B branch) €26–€156 €156–€455 €182–€611 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Questi codici compaiono spesso insieme a P0407 o indicano problemi correlati:

P0401P0402P0403P0404P0405P0406P0408

Domande frequenti su P0407

What is the difference between EGR sensor A and sensor B?

Sensor A is the primary EGR position feedback. Sensor B is the secondary, present on engines with two EGR valves (most V6/V8 diesels) or on engines that use a redundant feedback sensor. On most 4-cylinder engines there is no sensor B, so P0407 only appears on more complex setups (Audi 3.0 TDI V6, Mercedes V6 diesels, some BMW B57).

Can I drive with P0407?

Short-term yes. The ECU disables the affected EGR bank and falls back on the other bank, causing uneven idle and reduced power. Diesels may enter limp mode. Plan the repair within a couple of weeks to avoid carbon buildup or DPF problems.

Does my 4-cylinder car have an EGR sensor B?

Usually no. P0407 on a 4-cylinder engine usually means the workshop manual labels the existing single sensor as 'B' due to manufacturer convention, or the engine has a primary plus secondary feedback (rare). On VW EA189/EA288, BMW N47/B47, and Mercedes OM651, the relevant code is normally P0405 not P0407.

Is repairing P0407 worth it on a high-mileage diesel?

Yes, in most cases. EGR sensor or valve replacement is far cheaper than dealing with a clogged DPF, NOx sensor faults, or AdBlue limp-mode countdown that result from continued EGR failure. On Audi 3.0 TDI V6 with dual EGR, budget for both sides to be inspected, since one failure often signals the other is close behind.

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Esegui la scansione della tua auto con Skanyx per diagnosticare P0407

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