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OM642 320CDi rail pressure too low

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by zedmeister, Jan 27, 2014.

  1. zedmeister

    zedmeister Senior Member

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    Location:
    Watford, Herts.
    Your Mercedes:
    SL R107/1985/2.8, CLK C208/2002/3.2, E Class W213/2017/220d, SL R230/2003/5.4K
    Hi
    Well I'm having fun with my OM642 as well. After changing endless bits in the last year for various fault codes that have cleared up those issues (such as exhaust back pressure sensor, lambda sensor, Air mass sensor, etc) I am currently left with:

    2047 Rail Pressure monitoring via volume control valve The rail pressure is too low.

    The car is a CLS320CDi with Brabus D6. The indie is always suggesting with every fault that removing the Brabus kit will sort it or is the first step to diagnosis! I have changed the fuel filter but to no avail. The car has done 85k miles and drives fine with normal acceleration except when accelerating hard where it jerks and does not accelerate. If I take my foot off, its back to normal, if I keep my foot in, the engine light comes on with the above code. Any suggestions?
     
  2. GAD Tuning LTD

    GAD Tuning LTD Forum Supporter Authorised Forum Supporter

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    Your Mercedes:
    Mercedes W205 C63s Edition 1 - C350 CDI
    I would also recommend taking the Brabus kit off as its not the same as mapping a vehicle because you will increase the rail pressure and then increase to limiter also. But with the Brabus kits and other tuning boxes it merely retards the rail signal so having your Brabus kit on it currently will being giving false readings.

    Many thanks

    The GAD Team
     
  3. OP
    zedmeister

    zedmeister Senior Member

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    Your Mercedes:
    SL R107/1985/2.8, CLK C208/2002/3.2, E Class W213/2017/220d, SL R230/2003/5.4K
    Update : taking the Brabus unit off fixes everything. Any suggestions?
     
  4. toby1

    toby1 Senior Member

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    Your Mercedes:
    1998 CL420 C140
    Leave it off?
     
  5. whitenemesis

    whitenemesis Senior Member

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    Your Mercedes:
    CLS55 AMG '05
    Leave it off and get the car remapped properly..
     
  6. OP
    zedmeister

    zedmeister Senior Member

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    Your Mercedes:
    SL R107/1985/2.8, CLK C208/2002/3.2, E Class W213/2017/220d, SL R230/2003/5.4K
    And lose 48hp? It's just a boring diesel without the Brabus unit!
     
  7. whitenemesis

    whitenemesis Senior Member

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    Not if you had it properly remapped, speak with the guys at GAD ;)
     
  8. Corned

    Corned Senior Member

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    Your Mercedes:
    2005 S211 E320CDI Avantgarde
    Then just live with the fault codes! :rolleyes:
     
  9. GAD Tuning LTD

    GAD Tuning LTD Forum Supporter Authorised Forum Supporter

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    Your Mercedes:
    Mercedes W205 C63s Edition 1 - C350 CDI
    Your problem is that the brabus unit is tricking the ECU and rail pressure thinking its lower than it is if this goes below the threshold you will get this error.

    As we have said time and time again to members the box tricks the ecu into thinking the pressure is lower than it is, hence making the ecu compensate for the "apparent" lack of pressure.

    Our honest advise would be to look in to remapping as this is the ONLY effective way of do this.

    We have two of the WORLDS fastest diesel Mercedes and we did not achieve this by a tuning box.

    There is so much more to tuning a diesel other than a rail pressure or Boost box.


    If you need any help or advise please just ask.

    Regards Team GAD
     
  10. Uncle Benz

    Uncle Benz Senior Member

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    Brabus boxes do break, in my experience...
     
  11. Bubble

    Bubble Senior Member

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    Your Mercedes:
    E350 Coupe CDI / Land-Rover Discovery 4 / Nissan Skyline 650bhp R.I.P.
    I have had both my cars mapped by GAD and the only problem has been the ache from the big grin on my face :D

    I have previously used tuning boxs on Mondeo diesels and they have caused problems with the check light coming on and then going into limp home mode.
     

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