EmissionsModerate✅ DIY Friendly

P0402

Q: What does OBD2 code P0402 mean?

P0402 means: Exhaust Gas Recirculation Excessive Flow. Too much EGR flow detected.

Exhaust Gas Recirculation Excessive Flow

Too much EGR flow detected.

SeverityModerate

CategoryEmissions

Est. Repair Cost$100–$500

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›EGR valve stuck open
›Faulty EGR solenoid
›Incorrect EGR valve
›Vacuum leak to EGR causing constant flow

⚠️ Symptoms

›Rough idle
›Stalling at idle
›Check engine light
›Engine runs poorly at low RPM

✅ How to Fix — Step by Step

Step 1:Test EGR valve for sticking open
Step 2:Replace EGR solenoid
Step 3:Check vacuum supply
Step 4:Replace EGR valve

🔧 Diagnostic Tools Required

✔OBD-II Diagnostic Scanner
✔Digital Multimeter
✔Basic Hand Tools
✔Flashlight
✔Vehicle Service Manual

Using the correct diagnostic tools helps identify the root cause of P0402 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: An EGR valve stuck open causes very rough idle and stalling — the engine acts like it has a massive vacuum leak.

Frequently Asked Questions

What does OBD2 code P0402 mean?+

P0402 stands for Exhaust Gas Recirculation Excessive Flow. Too much EGR flow detected.

What causes code P0402?+

EGR valve stuck open; Faulty EGR solenoid; Incorrect EGR valve; Vacuum leak to EGR causing constant flow

How do I fix code P0402?+

Test EGR valve for sticking open; Replace EGR solenoid; Check vacuum supply; Replace EGR valve

How much does it cost to fix P0402?+

Estimated repair cost for P0402 is $100–$500.

Is P0402 DIY-friendly?+

Yes — P0402 is generally DIY-friendly with basic tools.

AI Diagnosis

🤖 AI-powered diagnosis for P0402 is coming soon.