EGR control electrical fault.
P0403 — also written PO4O3, P 0403, 0403 — is the OBD-II code for egr control circuit. Same code, same fix: this page covers every spelling of it.
This is a straight-up electrical 'break' in the EGR system, usually meaning the solenoid coil has fried or the wiring's been chewed through. It's properly common on VAG 1.6 and 2.0 TDi engines where the valve is buried at the back.
P0403 is a emissions fault code, typically costing £100–£500 to put right in a UK garage.
What P0403 actually feels like to drive
- The 'Glow Plug' light flashing or EML on constantly.
- Car suddenly goes into 'Limp Home' mode, feeling like you've lost 50bhp.
- Engine runs perfectly fine for 5 minutes, then cuts power as soon as it warms up.
- A weird clicking or chattering sound from the engine bay after you turn the key off.
- Cruise control suddenly stops working for no apparent reason.
What causes P0403?
- Failed EGR solenoid
- Wiring
UK vehicles that throw P0403 most often
- VW Golf / Passat 1.6 & 2.0 TDi (Common Rail) 2009-2015
- Vauxhall Astra J / Insignia 2.0 CDTi (A20DTH) 2008-2015
- Ford Focus / Mondeo 2.0 TDCi (Duratorq) 2010-2014
- Audi A3 / A4 2.0 TDi (CAGA/CAHA engine codes) 2008-2013
- Land Rover Freelander 2 / Discovery Sport 2.2 SD4
How P0403 is fixed
- Solenoid replacement
The P0403 misdiagnosis that wastes money
I see so many lads just throwing a cheap eBay EGR valve at this without even popping the bonnet to look at the loom. P0403 isn't about carbon buildup; it's an electrical circuit fault. I’ve had more than one Astra come in where the previous garage replaced the valve three times, but the actual culprit was a tiny break in the wiring harness near the gearbox mount or a corroded pin in the ECU plug. If you don't check for 12V and a PWM signal first, you're just guessing with the customer's wallet.
What a UK garage should charge for P0403
Pricing is a postcode lottery. For a basic Focus or Astra, a decent Bosch or Delphi valve is about £120-£180 from the factors, plus 2 hours labour, so you're looking at £250-£350. But if you're in a VW or Audi with the EGR at the back, the part is £250 and the labour is massive—often 5 to 7 hours. You won't get much change from £600-£800 at an indie, and a main dealer will easily quote you over a grand. Always stick to OE brands; the £40 'no-brand' specials from Amazon usually last about three weeks.
P0403 repair cost in the UK
Most P0403 repairs land between £100–£500 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 P0403
If your local garage says "you need a new EGR" for a P0403, ask them if they've done a 'continuity and load test' on the wiring. A simple multimeter check isn't enough; you need to see if the wires can actually carry current. Also, if you’re driving a VW or Audi, insist they check the EGR cooler motor specifically. These are a nightmare to get to on the back of the engine, often taking 5-6 hours of labour. Don't let them bill you for a 'quick' job then call back four hours later crying about how hard it is — they should know the book time up front.
Can you drive with P0403?
Drivable.
Urgency: medium.