P0402Medium urgency
Exhaust Gas Recirculation Flow Excessive
Emission · EGR System
⚠️ May cause rough idle and stalling. Service within 1 week.
What this means
The EGR system is flowing more exhaust gas than commanded. Too much EGR causes rough idle, hesitation, and stalling as exhaust dilutes the intake charge excessively.
Likely causes
- Stuck-open EGR valveMost common
- EGR valve stuck partially open from carbonMost common
- Faulty EGR differential pressure sensorCommon
Estimated repair cost
EGR valve cleaning or replacement$80 – $400
EGR DPFE sensor$50 – $200
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Frequently asked questions about P0402
What does P0402 mean?
The EGR system is flowing more exhaust gas than commanded. Too much EGR causes rough idle, hesitation, and stalling as exhaust dilutes the intake charge excessively.
Is P0402 serious?
May cause rough idle and stalling. Service within 1 week.
How much does it cost to fix P0402?
Repair costs for P0402 range from $80 – $400 depending on the root cause and your vehicle.
Can I drive with P0402?
You can drive short distances but should have it repaired within 1–2 weeks to prevent further damage.