P0400
Exhaust Gas Recirculation Flow Malfunction
Description
Exhaust Gas Recirculation Flow Malfunction. This powertrain diagnostic trouble code covers the engine, the fuel and ignition systems, emission control and the transmission.
OBD Codes Details
Possible Causes
Failed catalytic converter, leaking EVAP hoses or purge valve, clogged EGR passages, faulty oxygen sensor
Solution
Check upstream and downstream oxygen sensor readings, smoke-test the EVAP system, inspect the EGR passages and valve, evaluate catalyst efficiency
Symptoms
- Engine performance issues
- Reduced power or acceleration
- Poor fuel economy
- Engine running rough
Diagnostic Recommendations
- Scan for additional powertrain codes
- Check engine performance parameters
- Inspect fuel and ignition systems
- Test sensors and actuators
Repair Cost Estimate
- Basic diagnostic: $100-200
- Sensor replacement: $100-500
- System repair: $200-1500
- Major engine work: $1000-5000
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
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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