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250 Engine loom schematic

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by hooverphonique, Sep 9, 2024.

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  1. Sep 9, 2024 #1
    hooverphonique

    hooverphonique

    Hi,

    my 20212 250 has thrown a P0340 (cam sensor circuit fault) a couple of times recently (no other codes), and wanting to test the wiring, I looked for an engine loom schematic.

    Catcar doesn't seem to have this, so can anyone here advice on somewhere to look this up, or perhaps post the required schematic part for cam sensor to ecu?
     
  3. Sep 9, 2024 #2
    hooverphonique

    hooverphonique

    Also, is the cam sensor the one located next to the oil level stick, or next to cyl 4 ignition coil?
     
  4. Sep 10, 2024 #3
    Zoto

    Zoto

    Near dipstick - 1265 - inlet cam position sensor
    Near #4 cylinder - 1603 - solenoid that varies oil flow to variable cam
     

    Attached Files:

  5. Sep 10, 2024 #4
    hooverphonique

    hooverphonique

    Thanks for that, Zoto!

    Still looking for a wiring diagram...
     
  6. Sep 10, 2024 #5
    Zoto

    Zoto

    I'll send you one tomorrow
     
  7. Sep 10, 2024 #6
    autronix

    autronix RSM Club Member

    do you happen to have the EMS3125 version?

    some programms this is listed EMS3125 but the wiring diagram is for older EMS3110 ECU.

    the EMS3125 uses a 5 wire wideband sensor and pinout is not the same.

    as a quick check to differentiate from EMS3110 is:


    EMS3125 MAP sensor:
    1. green/black to connector A (grey) PIN D1
    2. orange/black to connector A (grey) PIN J1
    3. white/red to connector A (grey) PIN E4

    EMS3125 Boost sensor / (on inlet tube after the intercooler)
    1. orange/black to connector A (gray) PIN A1
    2. white to connector A (gray) PIN B2
    3. white/balck to connector A (gray) PIN J3


    EMS3125 VTC CTRL solenoid
    1. 12V
    2. CTRL to connector B (brown) PIN 1K

    many many thanks
     
  8. Sep 11, 2024 #7
    Zoto

    Zoto

    No - only EMS3110 (250/265)
     
  9. Sep 11, 2024 #8
    Zoto

    Zoto

    I've attached the ECU schematic and plug connection diagrams for sensor and solenoid.
    I had a look thru the ECU (120) plug connection diagram, but there are multiple options and I'm not sure which is correct for you, and to be honest I can't find one that has both the camshaft position sensor and solenoid shown, which is weird.
     

    Attached Files:

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  10. Sep 13, 2024 #9
    hooverphonique

    hooverphonique

    Thanks for your efforts, I'll see what I can make of this :-)
     
  11. Sep 13, 2024 #10
    autronix

    autronix RSM Club Member

    hooverphonique likes this.
  12. Sep 15, 2024 #11
    Zoto

    Zoto

  13. Sep 15, 2024 #12
    hooverphonique

    hooverphonique

    So with the help of the lovely people in this thread, I've now established the following:

    - the sensor gets power with ignition on (12V)
    - there is continuity between the sensor signal pin and the input pin in the ecu connector
    - the sensor emits a signal with a frequency that is rpm-dependent (freq rises with rpm)

    I measured the signal using a multimeter, so don't really know what it looks like, or the integrity of it, other than the frequency changes.
    Is it likely that the sensor (if faulty) outputs an rpm-dependent signal, but with a signal integrity problem causing the ecu to report a circuit fault?
     
  14. Sep 15, 2024 #13
    autronix

    autronix RSM Club Member

    Hi mate , yes I have, if you need something just let me know.
     
    Zoto likes this.
  15. Sep 15, 2024 #14
    autronix

    autronix RSM Club Member

    the cam sensor is an hall effect sensor and will produce a square wave 0 - 5V (usually) or 0 - 12V , etc and will change the frequency vs rpm.

    to check it you need an oscilloscope , with the multimeter you can test just the continuity, shorts etc.
     
  16. Sep 18, 2024 #15
    Zoto

    Zoto

  17. Sep 26, 2024 #16
    hooverphonique

    hooverphonique

    Based on the above, I concluded that it was more likely, the sensor output had gone wonky, than the ecu was faulty, so I've exchanged the sensor with an aftermarket one, and the sensor circuit DTC is now gone...
     

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