The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P0404.
DTC/P0404·BMW
P0404 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)BMW
P0404 on a BMW means the EGR valve is responding to ECU commands, but not within the expected position range. The ECU asks for a specific opening (say 30%) and the position sensor reports something different. Carbon buildup restricting valve travel is by far the most common cause.
Typical repair cost, all makes€68 - €1400
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BMW 3 Series
2007-2024On the N47 and B47 320d, P0404 typically appears around 100,000-130,000 km as carbon accumulates at the EGR valve seat and limits pintle travel. The position sensor reports the valve isn't reaching commanded angles. Cleaning sometimes works, but on chronically affected engines the EGR cooler-valve assembly is replaced as a unit since they are sold together. EGR adaptation must be reset with INPA, ISTA, or Carly after the job.
What causes P0404 on a BMW?
Beyond the generic causes listed on the main P0404 page, these are the patterns noted for BMW models:
BMW 3 SeriesN47/B47 pintle travel restriction from heavy carbon buildup at valve seat
BMW 3 SeriesEGR cooler-valve sold as one assembly, full replacement required
How to diagnose P0404 on a BMW with OBD2
Follow these steps to pinpoint the root cause of P0404:
- Use a scan tool to command the EGR valve through 0%, 25%, 50%, 75%, 100% and watch the position sensor feedback for delay or sticking
- Remove the valve and check for carbon buildup at the pintle and seat that limits travel
- Inspect the position sensor wiring and connector for corrosion or chafing
- Measure position sensor voltage at full closed and full open against the workshop spec
- After cleaning or replacement, perform the EGR adaptation procedure if the vehicle requires one (common on BMW, Mercedes, VAG)
How much does P0404 cost to fix on a BMW? (EUR)
Estimated repair costs for P0404 in EUR, compiled across makes. Expect BMW 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 P0404
These codes are often seen alongside P0404 or point to related issues, on any make:
Looking for the full P0404 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0404 guideSkanyx · BMW
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