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Fault code P0402 means excessive exhaust gas recirculation flow. The EGR valve recirculates more gas than requested, often because it stays partially open.

Typical symptoms

• Unstable idle and stalling
• Loss of power when cold
• Smoke and acrid smell
• Engine light on

Most common causes

• EGR valve stuck open by deposits
• Faulty return spring or actuator
• Miscalibrated EGR position sensor
• Vacuum leak in the control

How it is checked in diagnosis

• Reading requested and actual valve position
• Full closure test in diagnosis
• Inspection of the valve seat
• Checking the control circuit

Can you drive with code P0402?

Yes, but the engine runs rough especially when cold: best to act soon.

How MasterTuning helps

We read the real values from the ECU, not just the code: that is the difference between identifying the component responsible and replacing parts by trial and error. After the repair we clear the fault and check that it does not come back. Centres throughout Italy.

Read more: vehicle database · find an installer · what is ECU remapping

Do you have code P0402 on your car? Book a diagnosis at your nearest MasterTuning centre.

Frequently asked questions

What does fault code P0402 mean?

Code P0402 means excessive exhaust gas recirculation flow. The EGR valve recirculates more gas than requested, often because it stays partially open.

Can you drive with fault P0402?

Yes, but the engine runs rough especially when cold: best to act soon.

Is clearing code P0402 enough to fix it?

No: if the cause is still present the code comes back after a few kilometres. Clearing should only be done after the repair, with the diagnostic tool.

How much does it cost to fix code P0402?

It depends on the component responsible: the diagnosis is precisely what identifies it with real measurements, avoiding unnecessary replacements that cost far more than the correct repair.