P0402 — Exhaust Gas Recirculation Flow Excessive Detected
Category: Powertrain Severity: Medium
Updated:
DTC code P0402 means: Exhaust Gas Recirculation Flow Excessive Detected. It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include faulty EGR valve stuck open or malfunctioning, faulty EGR position sensor and wiring/connector issue; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Faulty EGR valve stuck open or malfunctioning
- Faulty EGR position sensor
- Wiring/connector issue
- Carbon buildup affecting valve movement
Symptoms
- Rough or unstable idle
- Engine hesitation or stalling
- Check engine light on
- Possible failed emissions test
How to diagnose it step by step
- Check whether the EGR valve stays open at idle.
- Clean the valve and its seat.
- Check the control solenoid.
- Replace the valve if it doesn't close.
How to fix it
Check the EGR valve for carbon buildup that could keep it stuck; clean or replace it if needed. Test the position sensor and its wiring separately before assuming the valve itself is bad.
Estimated repair cost
Cleaning: $100–250. Valve: $200–650.
Frequently asked questions
What does DTC code P0402 mean?
Exhaust Gas Recirculation Flow Excessive Detected.
Is code P0402 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0402?
Carefully: an open EGR causes stumbling and may stall the engine at idle.
Related codes
P0401 P0403 P0400 P0404 P0405 P0406 P0410 P0411 P0420 P0421
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