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How to identify all turbo control valves and replace the compressor discharge (dump) valve.

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  • OVERALL DIFFICULTY INDEX: 2/10
  • IF YOU HAVE NO TOOLS YOU SPEND $5 TO GET THEM FOR THIS JOB
  • IF YOU HAVE NO EXPERIENCE YOU SPEND 25 MINUTES TO CARRY OUT THIS JOB
  • RISK OF BURNS, SEE BELOW

BEFORE YOU START
  • Turbo interventions are to occur on a cold engine only.
  • Never attempt working on an engine that has just been turned off. The turbo is too hot and the risks of burns or damage to the screws you are removing high.
  • The below works occurred on a Peugeot 5008 equipped with the EP6 156HP petrol engine. Works on many Peugeot, Citroën and Mini vehicles are identical, also similar for other turbos mounted on other engines.
DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.

Turbo control valves identification


Turbos are controlled by 3 different valves with 3 different functions.

LEFT: the Turbo Wastegate valve, a mechanical valve operated by a vacuum actuator.
It can only be visible after dismantling the catalytic converter.
It is normally open and continuously opens and closes up to various ratios as given by the ECU to regulate the turbo power.

MIDDLE: the Compressor Discharge Valve, a solenoid valve electrically operated. It is normally closed and opens only upon releasing the gas pedal following a sustained speed or an acceleration to avoid a turbo pressure surge. We are showing further below how to replace it.

RIGHT: the turbo regulation valve, a solenoid valve electrically operated that regulates the vacuum force used to control the Wastegate Valve. It connects the Wastegate Valve actuator to either the atmospheric pressure (to lower the turbo pressure) or to the turbo regulation vacuum reservoir (to increase the turbo pressure). Visit our turbo vacuum controls diagnostic page for more details.
Turbo wastegate:
Typical OCRs:
-Idle: 85%
-Lowest: 22%
​-Driving: 35-48%
Turbo dump valve:
Typical OCRs:
-Acceleration, driving: 0%
-Sudden deceleration: 100%
Turbo wastegate actuator (solenoid valve):
Typical OCRs:
See Wastegate OCRs

Replacing the turbo dump valve (compressor discharge valve)

Symptoms:
-Could generate "turbo dump valve stuck closed" or "turbo circuit pressure too low" codes 
-Slower acceleration
-Turbo pressure does not build up beyond 1200 mbar
-Triggers the ECU to voluntarily open the waste gate valve (OCR at 22%) on strong acceleration 
For replacing it:
Unplug the electrical connector, unscrew its 3 holding bolts, take it out, clean its seat with a soft cloth and refit the new valve!
That's it, it takes a minute.
Buy your turbo dump valve here, make sure of the compatibility with your vehicle:

See also our complete EP6 engine repair manual:

Or turbo diagnostics tips:
And more DIY tips for all types of cars: