The Quick Answer above is the generic definition. What follows is the model-specific detail for the Volkswagen models that log P0405.
DTC/P0405·Volkswagen
P0405 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Volkswagen
P0405 on a Volkswagen 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.
Typical repair cost, all makes€70 - €670
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Volkswagen Golf
2009-2024On 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.
What causes P0405 on a Volkswagen?
Beyond the generic causes listed on the main P0405 page, these are the patterns noted for Volkswagen models:
Volkswagen GolfEA189/EA288 harness chafing against EGR cooler shorting signal to ground
Volkswagen GolfConnector pin corrosion on early EA189 cars (2009-2012)
How to diagnose P0405 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0405:
- Back-probe the sensor signal wire with the key on, engine off. A healthy sensor at rest should read 0.5-1.0V (varies by vehicle, check workshop spec)
- Verify 5V reference at the sensor connector. If reference is missing, trace the wire back toward the ECU
- Unplug the sensor connector and inspect for water intrusion, corrosion, and bent pins
- With the connector unplugged, the signal wire should read 5V at the ECU side. If it reads 0V, the wire is shorted to ground
- If wiring and reference are good, the sensor itself is the most likely failure. On most modern systems, replacing the integrated valve assembly is the practical fix
How much does P0405 cost to fix on a Volkswagen? (EUR)
Estimated repair costs for P0405 in EUR, compiled across makes. Expect Volkswagen parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Codes related to P0405
These codes are often seen alongside P0405 or point to related issues, on any make:
Looking for the full P0405 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0405 guideSkanyx · Volkswagen
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