P0402: Exhaust Gas Recirculation (EGR) Flow Excessive
Too much exhaust is flowing back into the intake, usually because the EGR valve is stuck open.
Green, yellow, red: three ways P0402 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Code set once, idles fine.
Schedule a repair
Rough idle. Repair the EGR valve soon.
Stop and get help
Stalling at intersections. Don't drive until fixed; it's a safety issue.
Symptoms you might notice
- Rough idle
- Stalling at stops
- Hesitation
Common causes, cheapest first
- EGR valve stuck open with carbon
- Failed EGR valve
- Vacuum control problem
What you can check before calling
- Notice stalling when coming to a stop
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More egr codes
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0402 mean?
P0402 means "Exhaust Gas Recirculation (EGR) Flow Excessive". Too much exhaust is flowing back into the intake, usually because the EGR valve is stuck open.
Can I drive with code P0402?
It depends on what the vehicle is doing. Green: Code set once, idles fine. Yellow: Rough idle. Repair the EGR valve soon. Red: Stalling at intersections. Don't drive until fixed; it's a safety issue.
What causes P0402?
The most common causes are: eGR valve stuck open with carbon; failed EGR valve; vacuum control problem.
Is P0402 a serious code?
It can be. Stalling at intersections. Don't drive until fixed; it's a safety issue.
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