P0402 means the EGR system is flowing too much exhaust gas back into the intake manifold. The most common cause is an EGR valve stuck partially open, often due to carbon buildup on the valve seat. Diesel engines are especially vulnerable because of higher soot output.
DTC/P0402·Volkswagen
P0402 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Volkswagen
P0402 on a Volkswagen means the EGR system is flowing too much exhaust gas back into the intake manifold. The most common cause is an EGR valve stuck partially open, often due to carbon buildup on the valve seat. Diesel engines are especially vulnerable because of higher soot output.
Repair cost on Volkswagen€78 - €1610
What does P0402 mean on a Volkswagen?
Volkswagen Golf
2009–2024Golf TDI models with the EA189 (pre-Dieselgate) and EA288 (post-fix) engines commonly throw P0402 after the emissions software update was applied. The remapped EGR strategy runs the valve at higher duty cycles, which accelerates carbon buildup at the seat. Cleaning the valve and intake manifold passages restores normal operation. On 1.4 TSI petrol Golfs, the integrated EGR cooler in the exhaust manifold can also stick open.
What causes P0402 on a Volkswagen?
Beyond the generic causes listed on the main P0402 page, these are the Volkswagen-specific patterns we see most often:
Volkswagen GolfEA189 post-Dieselgate software update accelerating EGR valve carbon buildup
Volkswagen GolfEA288 intake manifold runners clogged from heavy EGR duty cycle
How to diagnose P0402 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0402:
- Read freeze frame data and check whether the fault appears at idle, cruise, or under load
- Remove the EGR valve and inspect the seat and pintle for carbon buildup preventing full closure
- Command the EGR valve closed with a scan tool and verify it seats fully (position sensor should read 0%)
- Inspect vacuum hoses (vacuum-operated systems) for leaks that hold the valve cracked open
- On diesel engines, inspect the EGR cooler for internal damage and verify the MAP sensor reads correctly against a known-good reference
How much does P0402 cost to fix on a Volkswagen? (EUR)
Estimated repair costs on a Volkswagen (Volkswagen parts and labour typically run 15% 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 P0402 on Volkswagen
These codes commonly cluster with P0402 on Volkswagen vehicles:
FAQ: P0402 on Volkswagen
Can I drive with P0402?
Short distances yes, but expect rough idle and possible stalling. Excessive EGR flow dumps soot and exhaust into the intake, which accelerates carbon buildup on intake valves, especially on direct-injection engines. Get it diagnosed within a few weeks.
Is EGR delete legal in the EU?
No. EGR delete is illegal across the EU and UK. It increases NOx emissions, triggers a permanent check engine light, fails the periodic technical inspection (TÜV in Germany, ITV in Spain, TA in Lithuania, SKP in Poland), and can result in vehicle deregistration. Stick to cleaning or replacement.
Will cleaning the EGR valve fix P0402?
Often yes. P0402 is usually caused by carbon stopping the valve from closing fully. Removing the valve, soaking it in EGR cleaner or carb cleaner, and clearing the seat resolves the code on roughly half of cases. If the solenoid or motor itself has failed, replacement is needed.
Why does my diesel keep throwing P0402 after cleaning?
Diesel engines produce far more soot than petrol, so the EGR valve re-fouls quickly. If the EGR cooler is also blocked or leaking internally, the valve will stick open again within months. On heavily affected engines (BMW N47, M57), the cooler often needs replacement alongside the valve.
Looking for the full P0402 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0402 guideSkanyx · Volkswagen
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