P0401
Exhaust Gas Recirculation Flow Insufficient Detected
Description
Exhaust Gas Recirculation Flow Insufficient Detected This body system diagnostic trouble code indicates an issue with the vehicle's comfort, safety, or convenience systems.
OBD Codes Details
Possible Causes
Blown fuse, faulty switch, damaged wiring harness, poor electrical connection
Solution
Check fuses and relays, inspect wiring harness, test switches and sensors, repair damaged circuits
Symptoms
- Check engine light illuminated
- Engine pinging or knocking, especially under load
- Rough idle
- Increased NOx emissions, failed emissions test
- Hesitation during acceleration
Diagnostic Recommendations
- Inspect EGR valve for carbon buildup preventing it from opening
- Test EGR valve operation with a scan tool
- Check EGR passages and ports for blockage
- Inspect EGR solenoid and vacuum lines (if equipped)
- Verify EGR flow using live data during a commanded test
Repair Cost Estimate
- EGR valve cleaning: $50-150
- EGR valve replacement: $150-450
- EGR passage cleaning: $100-300
- Diagnostic scan: $80-150
- Total diagnostic and repair: $150-800
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
Last updated:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
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