Passat 2.0 TDI oil pressure out of range

[MKLTD]

Hi All, I have a 2017 2.0 tdi passat with an oil pressure out of range error. The car goes into limp mode and the coil light flashes on the dash. I have already thrown the parts canon at it and replaced the oil pressure switches (brown and green) and the oil control solenoid. It has a new VW oil filter and fresh oil. The engine sounds fine, like it has oil pressure and doesn't idle rough or anything like that.

Can anyone work out what the fault could be from the scan below. What do the oil pressure switch bits mean? or any other clues?

Thursday,08,June,2023,16:28:39:38498
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64)  HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN: WVWZZZ3CZHE177014   License Plate: VN17



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                Address 01: Engine       Labels: 04L-907-309-V1.clb
Control Module Part Number: 04L 906 026 ES    HW: 04L 907 309 R
  Component and/or Version: R4 2.0l TDI   H24 1989
           Software Coding: 0119001203451D083000
            Work Shop Code: WSC 00015 115 08193
              ASAM Dataset: EV_ECM20TDI01104L906026ES 002002 (VW48)
                       ROD: EV_ECM20TDI01104L906026ES_002_VW48.rod
                      VCID: 7F5B0A3B77741AD2761-802A
1 Fault Found:

5580 - Engine Oil Pressure
          P055F 00 [109] - Out of Range
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 148432 km
                    Date: 2023.06.05
                    Time: 11:02:34

                    Engine RPM: 1645.50 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 28 km/h
                    Coolant temperature: 35 °C
                    Intake air temperature: 43 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 14.920 V
                    Unlearning counter according OBD: 40
                    Fuel consumption: 0.00 l/h
                    Engine oil temperature: 13.8 °C
                    Status of oil pressure switches-Bits 0-7: 5
                    Oil fill level: 57.640 mm
                    Outside temperature sensor 1: B1: raw value: 15.5 °C
                    Fuel temperature sensor 1: B1: raw value: 17.0 °C


Readiness: 0 0 0 0 1

 

[Uwe]

What do the oil pressure switch bits mean?

I've never seen any documentation for that.

Have you put a mechanical gauge on it to see what's really going on with the oil pressure?

Possibly a wiring problem to one of the switches?

-Uwe-

 

[dieseldub]

From what I understand about this system, it's a variable displacement vane oil pump. There are two oil pressure switches, a high and a low. The high pressure switch is basically ignored unless the RPMs are above 3000 RPM, which is also when the high pressure stage is supposed to be engaged.

Low pressure is supposed to remain engaged from idle to about that 3000 RPM mark.

So, with that being said, it seems a little strange that it's unhappy with the oil pressure situation at just 1645 RPM according to the freeze frame.

Would be good to get an actual oil pressure gauge on it, as Uwe recommended, and see what it does near that 1600 RPM mark and keep going until 3000, see if you notice a sudden jump in pressure as the high pressure stage is supposed to engage. Though, I'm not sure if the computer stops trying to modulate the pump when there's an active detected problem with one of the switches.

As far as I can tell, these are still just two different pressure switches with different pressure ranges, so it's not really sending the ECU actual oil pressure information, just a yes or no on if the pressure is above the specified ranges.

So, I suppose the one thing that could upset the ECU at this RPM range is actual low pressure switch being tripped at that RPM.

So yes, definitely put a gauge on it, see what pressure it actually has. Make sure you have the correct plug on the correct switch, do a continuity test from the low pressure switch wire to the ECU, see what you get.

 

[MKLTD]

The fault happens at multiple rpm ranges. The next time it registers the same code it could be at 3500 rpm for example. So i agree it could be a genuine low oil pressure. I would have thought that a low oil pressure code would show instead of just out of range. Out of range to me sounds like the ECU cannot determine something. As you both have mention a mechanical pressure gauge would be the next best option for fault finding to rule out a true pressure issue.