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Vsc brake system p400 code

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The vsc system engine light back on 12 avensis d4d down power only about half boost rattle my head trying solve problem 

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P0400 is an EGR or EGR flow malfunction, there is something blocking the EGR system such as carbon buildup or a stuck valve and it is an engine related fault so you will have an engine management warning light on along with messages about VSC malfunction however the VSC is upset because the EML is on

DTC Code DTC Name
P0400 Exhaust Gas Recirculation Flow


The EGR system recirculates exhaust gases. The recirculated gas mingles with the intake air so that the EGR system can slow combustion speed and keep the combustion temperature down. This helps reduce NOx emissions.

In order to increase EGR circulation efficiency, the ECM adjusts the EGR valve angle and the throttle valve angle.

P0400 (EGR valve malfunction)
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
After warming up engine and idling for 60 seconds, maintain engine speed at 2500 rpm for 40 seconds, drive vehicle, and perform engine brake deceleration by fully closing accelerator when engine speed is 2000 rpm or more.

The target and actual positions of the EGR valve are different for 40 seconds or more.

(1 trip detection logic)

  • EGR valve stuck

  • EGR valve does not move smoothly

  • Open or short in EGR valve circuit

  • EGR valve deposit

  • ECM

P0400 (Flow malfunction)
DTC Detection Drive Pattern DTC Detection Condition Trouble Area

After warming up the engine, decelerate from a speed of 80 km/h (50 mph) or more (fully release the accelerator pedal for approximately 5 seconds).

Tech Tips

  • Intake Air: -7 to 40°C (19 to 104°F)

  • Engine Speed: 1500 to 2400 rpm

  • Vehicle Speed: 46 km/h (29 mph) or more

Mass air flow rate is not changed when turning on the electric EGR control valve while decelerating.

(2 trip detection logic)

  • EGR valve deposit

  • EGR valve passage deposit

  • Air intake system (leaks or blockages)

  • Exhaust gas leaks

  • ECM

  • Mass air flow meter

  • Manifold absolute pressure sensor

Related Data List
DTC No. Data List

P0400 (EGR valve malfunction)

P0400 (Flow malfunction)

  • MAF

  • MAP

  • EGR Close Lrn. Val.

  • EGR Close Lrn. Status

  • Target EGR Position

  • Actual EGR Valve Pos.

Tech Tips

  • Actual EGR valve opening percentage: Fully closed = 0%, fully open = 100%.

  • If DTC P0400 is stored, the following symptoms may appear:

    • Stuck closed malfunction

    • Intake booming noise

    • Slight combustion noise

    • Stuck open malfunction

    • Black smoke

    • Lack of power

    • Vibration at engine stop


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  • 4 weeks later...

So what have you done about it, removed , cleaned, tested,diagnosed?

The engine ECU is detecting insufficient air flow through the EGR system attached is a pic of the EGR routing:

Green is the route of the exhaust gas from the exhaust through EGR Cooler onto the first EGR Valve then through the side if the cylinder head and onto the main EGR valve before entering the intake manifold there could be a blockage of carbon or either of the valves could be stuck/sticking shut. 

There aren't any EGR blanking plates fitted?


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No egr plate fitted take it to dealer now next to put it up on computer  and get decision then an what next step 

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