A friend has a 2010 Peugeot Partner II with a 1.6L turbo diesel engine. It was idling horribly with white smoke and had no power under acceleration. When I floored the accelerator parked it would belch white and black smoke. I hooked up a scan tool and saw 5 EGR codes and guessed that the EGR was stuck open. Pulled the EGR and verified it. EGR solenoid was toast, but was able to force it into the closed position and put it back without plugging in the connector. Engine idled fine after that. However flooring the accelerator was still causing white smoke and when I took it for a test drive it still lacked power. Scan tool shows that the measured turbo pressure is never getting above 1000 mbar - or about 10% above atmospheric pressure up here in the mountains.

Is it possible that the ECU might be in some kind of limp mode and disabling the turbo when it sees a non-functioning EGR?

  • Can you tell if the wastegate is being opened?
    – HandyHowie
    Commented Feb 3, 2021 at 12:32
  • @HandyHowie Forgot to check that... But I'm thinking it's not the ecu, as the engine revs up to almost 5k rpm and the turbo pressure reference value gets up to 2 Bar. Commented Feb 3, 2021 at 12:50
  • What are the codes?
    – GdD
    Commented Feb 3, 2021 at 12:52
  • So 2 bar as per comment or 1 bar as question...
    – Solar Mike
    Commented Feb 3, 2021 at 12:54
  • @SolarMike 2 Bar is the ref value - i.e. what's being targeted / requested by the ECU. 1 Bar is the actual... The waste gate acuator seems fine. Not getting any vacuum to the actuator - so could be the hose, the boost solenoid or lack of command from the ecu, although I doubt it's the last since the ecu seems to be requesting 2 Bar... Commented Feb 3, 2021 at 14:44

1 Answer 1


So I did some testing and saw that the waste gate actuator is not getting any vacuum on start up. It should be getting vacuum enough to fully close it on startup.

I also manually held the waste gate closed while having someone hold the rpms steady at 3000 and verified that the turbo itself is working properly via scan tool showing the requested turbo pressure matching the measured turbo pressure.

During this test I saw the Turbo Pressure Solenoid Valve OCR showing 57% at 3k RPM with a Turbo Pressure Reference Value ( requested pressure ) of about 1500 mbar. This would indicate to me that the ECU is attempting to create boost.

So to answer my own question it seems like it's not the ECU or limp mode, there must be a problem with the vacuum hose, vacuum source or the boost solenoid itself.


Just to confirm, I changed the rubber hose that goes from the boost solenoid to the waste gate actuator and the vehicle reached near normal boost. Boost was slightly low ( below ref value ) at lower RPMs and basically matching ref value at high rpms.

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