P0403 means the ECU has detected an electrical fault in the circuit that controls the EGR valve. This is a wiring, connector, or solenoid problem rather than a mechanical valve issue. The ECU expected a specific voltage or current response and did not see it.
DTC/P0403·Audi
P0403 on Audi: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Audi
P0403 on a Audi means the ECU has detected an electrical fault in the circuit that controls the EGR valve. This is a wiring, connector, or solenoid problem rather than a mechanical valve issue. The ECU expected a specific voltage or current response and did not see it.
Repair cost on Audi€85 - €838
What does P0403 mean on a Audi?
Audi A4
2008–2024B8 and B9 A4 2.0 TDI models share the EA189/EA288 EGR valve with the Golf, so failure modes are identical. The tighter engine bay on the A4 makes the connector hard to inspect without removing the intake duct. On 3.0 TDI V6 models, each bank has its own EGR valve, so a P0403 may apply to either side. Always read the freeze frame to identify the correct bank.
What causes P0403 on a Audi?
Beyond the generic causes listed on the main P0403 page, these are the Audi-specific patterns we see most often:
Audi A4EA189/EA288 solenoid failure with poor connector access on B8/B9
Audi A43.0 TDI V6 single-bank EGR fault requiring freeze-frame to identify side
How to diagnose P0403 on a Audi with OBD2
Follow these steps to pinpoint the root cause of P0403:
- Inspect the EGR valve connector for corrosion, bent pins, and water intrusion
- Unplug the connector and measure resistance across the solenoid terminals. Compare against the workshop manual spec (typically 5–15 ohms for solenoids, 2–10 ohms for motors)
- Back-probe the connector and verify the ECU is supplying voltage and ground in the correct sequence when the EGR is commanded
- Inspect the harness between the ECU and EGR valve for chafing, especially where it routes near hot exhaust components
- If the solenoid and wiring test good, remove the valve and check whether carbon is mechanically binding the pintle
How much does P0403 cost to fix on a Audi? (EUR)
Estimated repair costs on a Audi (Audi parts and labour typically run 25% above the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0403 on Audi
These codes commonly cluster with P0403 on Audi vehicles:
FAQ: P0403 on Audi
Can I drive with P0403?
Yes, short-term. Some diesels go into limp mode to protect the catalyst or DPF, so plan the repair within a couple of weeks. Long-term driving with a faulty EGR circuit accelerates carbon buildup on intake valves and may cause secondary codes.
Is P0403 the EGR valve or the wiring?
Usually the valve itself. The solenoid winding inside electronic EGR valves is a common failure point, especially on diesels with heavy thermal cycling. Always inspect the connector first (the cheap fix), then test solenoid resistance before replacing the valve.
Should I delete the EGR system instead of fixing P0403?
No. EGR delete is illegal across the EU and UK, fails periodic technical inspection (TÜV, ITV, TA, SKP), and can void insurance. It also raises NOx emissions well above legal limits. Stick to cleaning, wiring repair, or valve replacement.
How long does an EGR valve last?
On petrol engines, 150,000 km or more is normal. On diesels, especially with city driving, 80,000–120,000 km is typical before carbon or solenoid issues appear. BMW N47/B47 and VW EA189/EA288 are well known for earlier failures.
Looking for the full P0403 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0403 guideSkanyx · Audi
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