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. Removing the EGR system breaks the emissions type approval the car was registered under, which is why it is prohibited across the EU. It increases NOx emissions, triggers a permanent check engine light, and gives an inspector grounds to reject the vehicle, with the checks and the penalties set by each country. 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 in a good share 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.

P0402: Exhaust Gas Recirculation Flow Excessive Detected

Quick Answer

Safe to drive (short-term)

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.

Severity: Moderate · Emissions
Estimated repair cost: From €68 to €1400+, varies by vehicle

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What does P0402 mean?

P0402 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0402 and illuminates the check engine light.

Where it is on the car

Engine
Exhaust manifold
EGR cooler (diesels and many newer petrols)
EGR valve and position sensor
Intake manifold

Too little or too much flow is often carbon in the valve or its passages, or a blocked cooler, not only a failed valve.

What are the symptoms of P0402?

If your vehicle has triggered P0402, you may notice one or more of these symptoms:

Check engine light illuminated
Rough or unstable idle, sometimes stalling at stops
Hesitation or stumble during light acceleration
Black smoke from exhaust under load (diesel)
Reduced fuel economy and slight loss of power

What causes P0402?

Here are the most common causes of P0402:

EGR valve stuck partially open from carbon buildup on valve seat
: high
Failed EGR valve solenoid or motor not closing fully
: high
Clogged or sticking EGR position sensor giving false readings
: medium
Damaged EGR valve diaphragm or vacuum hose leak (vacuum-operated systems)
: medium
Faulty MAP or DPFE sensor causing incorrect flow calculation
: low

Is it safe to drive with P0402?

Generally yes, for short-term driving. Driveable short-term, but excessive EGR flow causes rough idle, hesitation, and may stall the engine at low RPM. Extended driving with excess EGR contaminates the intake and accelerates carbon buildup on intake valves (especially direct-injection engines). Get it fixed before next emissions test.

How do you diagnose P0402?

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 manufacturer-level software (a generic OBD2 reader cannot run this test) 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?

Repair costs for P0402 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Clean EGR valve and passages	€8–€25	€60–€180	€68–€205	Moderate
Replace EGR valve (petrol or diesel)	€150–€450	€80–€220	€230–€670	Moderate
Replace EGR cooler assembly (diesel)	€300–€800	€250–€600	€550–€1400	Professional

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

EGR Valve Replacement Cost

P0402 on specific vehicles

P0402 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0402 on BMW

BMW 3 Series

See BMW-specific causes & cost

P0402 on Volkswagen

Volkswagen Golf

See Volkswagen-specific causes & cost

P0402 on Audi

Audi A4

See Audi-specific causes & cost

P0402 on Mercedes-Benz

Mercedes Sprinter

See Mercedes-Benz-specific causes & cost

These codes are often seen alongside P0402 or indicate related issues:

Common questions about P0402

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. Removing the EGR system breaks the emissions type approval the car was registered under, which is why it is prohibited across the EU. It increases NOx emissions, triggers a permanent check engine light, and gives an inspector grounds to reject the vehicle, with the checks and the penalties set by each country. 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 in a good share 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.

Read our detailed guides

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