P0402 Code: Exhaust Gas Recirculation (EGR) Flow Excessive Detected
🟠 Moderate severity · drivable
Drivable, but too much EGR flow causes rough idle and stalling, so fix it soon.
What P0402 means
Too much exhaust gas is being recirculated into the intake — more than the computer expects. This usually means the EGR valve is stuck open or its position sensor is reading wrong.
Symptoms
- Check engine light is on
- Rough idle
- Engine stalling at idle
- Hesitation on acceleration
Common causes
- most common: EGR valve stuck open
- common: Faulty EGR position sensor
- less common: Faulty DPFE sensor (Ford and others)
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Clean the EGR valve so it closes fully | Yes | $20–100 |
| Replace the EGR valve | Yes | $100–400 |
| Replace a faulty DPFE sensor | Yes | $40–120 |
Frequently asked questions
Can I drive with a P0402 code?
Yes, but too much EGR flow causes rough idle and stalling. Fix it soon.
What is the most common cause of P0402?
An EGR valve stuck open, usually from carbon buildup.
How much does it cost to fix a P0402?
Cleaning is $20–$100; a new EGR valve runs $100–$400.
Related codes
P0401
P0401 Code: Exhaust Gas Recirculation (EGR) Flow Insufficient Detected
P0400P0400 Code: Exhaust Gas Recirculation (EGR) Flow Malfunction
P0404P0404 Code: Exhaust Gas Recirculation (EGR) Circuit Range/Performance
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.