2015 1.6hdi 90bhp oil pressure fault

[Dave7494]

Hi everyone , new here and desperately seeking help , 

I have a 2015 Berlingo multi space 1.6hdi 90bhp 
Car has 191k miles and had timing and water pump done in last 12months and now recently due to f40a fault code showing oil pressure fault that intermittent had 2 new oil pressure switches from Citroen , new oil pump , full service and now had the mesh removed from oil pick up to test if that was maybe the issue but unfortunately driving it for 10 minutes tonight it’s shown back up with the fault and limp mode. 

I’m now at a complete loss to be honest , it’s an intermittent fault , when it comes on and I stop the car (fan keeps running in limp mode ) take key out and turn it back on the fan goes back to normal and the car is no longer in limp mode and like tonight after doing that it was driven 15miles mixed driving to see if I could throw the fault again but it didn’t come on. Sometimes it does sometimes it doesn’t. 

The wire to the oil switch looked ok aswell. 

Has anyone else experienced this or have any ideas of what I could be facing please 

Thank you for any help

[Sol]

What are you using to read the fault codes, as f40a can be a false code produced by certain firmware versions of ECU and Diagbox actually tells you it's a bug and to be ignored.

The limp mode could be a boost fault, low or high, a boost leak, or fuel pressure less than commanded, but with Diagbox you would know the real issue by looking at the codes and live data. That's why I was guessing you haven't got Diagbox as that code is usually not a genuine one although it relates to an oil sensor fault, Citroen know about it and Diagbox would flag it as a bug and not a genuine code.

Off the shelf code readers only get basic P codes from the engine ECU and not Citroen specific stuff but I had my last van 2 years, it had that phantom code and never ever went wrong or tripped limp mode. So I am certain it's not related and you need to get a proper Diagbox scan and live data checked for fuel pressure, boost commanded vs actual, cam to crank sync, airflow, EGR position etc.

[Dave7494]

Thank you very much for your reply and help. The diagnostics system used was an autel so you could very well be correct with that as when I pick the ecu p code side of the system it comes up with no faults stored. It’s only in the bsi side that this code shows saying oil gauge fault f40a

[Dave7494]

That would make sense though as the live data shows -40 engine oil temp so that would be pointing at the level / temp sensor. Just need to find it lol

[Sol]

Ok spot on. I'll have a look at Servicebox when I get to work tomorrow, and see where the sensor is for level / oil temp. I don't think there is an oil temp sensor but could be wrong, Citroen Servicebox will know. There is a level sensor and often goes wrong.

If there is an oil temp sensor and it's telling the ECU the oil is -40 then that could cause weird running errors. There was a Ford TSB for the Ranger truck and F150 showing mad negative temperature readings and it was blocking engine start even though the value was nonsense.

[Dave7494]

That’s fantastic thank you for all your help. Hoping it is that , had a look online and the sensor is listed as both level and temp so hoping that’s the case. Any help of location tomorrow would be a huge help
Thank you

[Sol]

You're correct, the sensor is numbered 4100 and is combined level and temperature. It's shown in the attachments below, schematic, wiring, colour scheme and location.

B9 Oil Warning System:

  Oil schematic.pdf (Size: 133.1 KB / Downloads: 44)

Colour Legend:

  legende.pdf (Size: 73.37 KB / Downloads: 21)

Sensor 4100:

  Sensor 4100.pdf (Size: 81.11 KB / Downloads: 40)

Location on Vehicle:

  Sensor Location.pdf (Size: 229.07 KB / Downloads: 42)

[Sol]

Also for the Limp mode issue, have a look at my How To post on that, linked below:

https://www.berlingoforum.com/thread-20797.html

[Dave7494]

Absolutely fantastic thank you so much

[tony.berthun@poka.com.au]

Also for the Limp mode issue, have a look at my How To post on that, linked below:

https://www.berlingoforum.com/thread-20797.html

Thanks Zion 
picked this thread up with the same problem with my belingo and bang.... found a split hidden unneath my intercooler top hose made a new hose and all faults went away 
Thankyou so much for saving me so much time and effort 
tony