P0402: Exhaust gas recirculation excessive flow detected
Drive carefully. Get it checked within a week or two.
Can I drive with P0402?
Yes, but drive carefully and get it checked soon. The EGR valve is stuck open, causing engine stalling at idle and low speeds.
What does P0402 mean?
P0402 stands for Exhaust Gas Recirculation Flow Excessive Detected.
Symptoms you may notice
- Spark knock (pinging or rattling) when accelerating uphill
- Rough, stumbling idle if valve is stuck open
- Slight drop in fuel efficiency
How much does it cost to fix?
Repair costs for code P0402 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- EGR valve stuck open by carbon debris
- Faulty EGR vacuum solenoid stuck venting
- Defective EGR differential pressure feedback (DPFE) sensor
- Short circuit in EGR wiring harness
What to do next
- Tap the EGR valve body gently to see if a stuck pintle closes.
- Remove and clean the EGR valve thoroughly with carb cleaner.
- Inspect vacuum lines to ensure vacuum is not applied at idle.
Last updated: October 2026
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General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code P0402 triggers when exhaust gas flows into the intake at idle or cold start when it should be blocked. The extra exhaust gas suffocates combustion, causing severe rough idle, bucking, or immediate stalling when you bring the vehicle to a stop. Cleaning out the stuck valve usually cures the problem.