EGR system not performing as commanded.
P0404 — also written PO4O4, P 0404, 0404 — is the OBD-II code for egr range/performance. Same code, same fix: this page covers every spelling of it.
P0404 means your EGR valve isn't moving to the position the ECU asked for, usually because it's physically jammed by UK 'stop-start' soot. I see this most on high-mileage 1.6 TDCi Fords and 2.0 CDTi Vauxhalls.
P0404 is a emissions fault code, typically costing £150–£700 to put right in a UK garage.
What P0404 actually feels like to drive
- The car feels 'flat' or gutless when you're pulling away from a roundabout.
- A noticeable 'chugging' or hesitation at steady motorway speeds (cruising at 70mph).
- Reduced fuel economy—you'll notice you're getting 5-8mpg less than usual.
- The engine idling roughly, feeling like it's about to stall when you stop at lights.
- Tapping or 'pinking' sounds under light acceleration when the engine is warm.
What causes P0404?
- Carbon buildup
- Stuck valve
- Sensor fault
UK vehicles that throw P0404 most often
- Ford Focus 1.6 TDCi (DV6 engine) 2008-2015
- Vauxhall Insignia 2.0 CDTi (A20DTH) 2009-2017
- Volkswagen Golf/Passat 1.6 TDI (EA189) 2009-2015
- Honda Civic 2.2 i-CTDi 2006-2011
- Land Rover Freelander 2 2.2 TD4 2006-2014
- Vauxhall Astra J 1.7 CDTi 2010-2014
How P0404 is fixed
- EGR service
- Carbon clean
The P0404 misdiagnosis that wastes money
I see so many lads just throwing a cheap £40 eBay EGR valve at P0404, only for the light to pop back on three days later. They forget that a clogged intake manifold or a split vacuum pipe often mimics a dead valve. We’ve had Insignias in where the owner replaced the valve twice, but the actual fault was the MAP sensor being so choked with soot it couldn't see the pressure change when the EGR opened. Always check the feedback signal on your scan tool before binning the hardware.
What a UK garage should charge for P0404
A basic diagnostic plug-in is £50-£80. If it's just a clean-up job using Wynns or Liqui Moly EGR cleaner, you're looking at £150. However, if the motor in the valve has fried, a quality Pierburg or Valeo replacement valve will cost £200-£350 for the part alone. Add 2 hours of labour at £70/hr, and you're hitting £500+. On the newer VWs where the valve is hidden behind the engine, labour can push the total bill closer to £750. Stay away from 'budget' factor parts; they rarely last a year.
P0404 repair cost in the UK
Most P0404 repairs land between £150–£700 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0404
If your garage tells you "it just needs a new valve," ask them if they’ve checked the EGR cooler and the pipework for carbon blockage. On the TDI engines, you can fit a new valve, but if the ports in the head are restricted, the P0404 will return because the airflow isn't what the ECU expects. Insist on a 'dynamic test'—we use the scan tool to command the valve open while watching the airflow drop. If they won't do that, they're just guessing with your wallet. Also, avoid 'EGR Delete' kits; they're an MOT failure if the tester spots the tampering.
Can you drive with P0404?
Drivable.
Urgency: medium.