Fault code P1400 – a step-by-step guide to diagnosing and fixing it

Error code P1400 is displayed and the check engine light is on - what does this mean?

The DTC P1400 is a manufacturer-specific error code that is recognized by the OBD system and indicates a problem with the exhaust gas recirculation system (EGR). This trouble code occurs when the EOBD system detects a malfunction in the EGR valve or its control circuit. The exact definition may vary slightly between manufacturers, but usually refers to EGR flow problems.

What can cause this error code?

• Defective EGR valve
• Blocked EGR lines or channels
• Damaged vacuum hose system
• Defective EGR position sensor
• Faulty wiring to the EGR system
• Defective EGR control unit
• Clogged intake manifold
• Loose or corroded plug connections
• Defective pressure sensor in the EGR circuit

What symptoms occur in parallel with fault code P1400?

• Loss of engine power: Reduced acceleration and reduced top speed
• Unsteady idling: Engine runs unevenly at idle speed
• Increased fuel consumption: Significantly higher consumption than usual
• Knocking noises: Metallic noises from the engine compartment
• Black smoke: Dark exhaust fumes from the exhaust pipe
• Starting problems: Difficulty starting the engine

How to fix the problem of error code P1400?

• The repair requires a systematic diagnosis of the EGR system and the associated components.
• Clean or replace the EGR valve: Remove the valve, clean thoroughly with brake cleaner or replace with a new valve if irreparably damaged
• Flush EGR lines: Check all vacuum hoses and lines of the EGR system for blockages and flush with compressed air or special cleaning agents
• Check electrical connections: Check all plug connections, cables and contacts of the EGR system for corrosion, damage or loose connections and repair them
• Replace EGR position sensor: Test the sensor for proper function and replace with an original part if defective
• Clean the intake manifold: Dismantle the intake manifold and remove any carbon deposits that may obstruct the EGR flow
• Update control unit software: Have the specialist workshop check whether software updates are available for the engine control unit that rectify known EGR problems