This is a wierd one. So when I put the key in and press once before starting the engine, a warning and beeps say 'low oil pressure do not start engine'. Surely with the engine not running, the oil will not be under pressure. Am I looking at a new switch?

Definitely try a new switch or an oil flush. 

Hello Richard,

You could try a new switch, but try will be the operative word, since you don’t know that there isn’t any stored information that the oil pressure was actually low when last used. 
If it were mine, I wouldn’t now be just changing the sensor (programming-in part?) but first getting the actual running pressure assessed. That way, there is unlikely to be any assumption associated with your issue. 
Kind regards,

Gareth. 

ok, so i went and got me a vcds. tis thing is pretty gd. this is the fault code i keep getting. ive changed the high pressure switch at the bottom of the block but really hoping i dont need to do the low pressure one as it looks a pig to get to.

1 Fault Found:

5581 - Oil Pressure Switch 
          P164A 00 [039] - Implausible Signal
          Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 5
                    Mileage: 203152 km
                    Date: 2021.07.03
                    Time: 14:55:55

                    Engine RPM: 0.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 20 °C
                    Intake air temperature: 23 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 9.980 V
                    Unlearning counter according OBD: 40
                    Crankshaft speed (RPM): 0.0 /min
                    Vehicle speed: 0.00 km/h
                    Vehicle voltage terminal 30: 14060 mV
                    Accelerator position: 0.00 %
                    C Eng Ds T u Raw: 1238.6 mV
                    Co Eng st: COENG_READY
                    Engine oil temperature: 46.7 °c

if someone can give me of advice on the fault or vcds i would appreciate it.
 

 

 

Yea looks like a faulty switch. 

   Hi,

Did you fix the issue ? I have a similar problem on my high mileage 2009 Audi A4 B8 allroad 3.0 TDI CCWA engine. The car had 2 oil pressure switch sensors replaced by my local garage without any luck (error code not clearing). As Gareth mentioned earlier on the post are these sensors programming-in parts ?

The oil pressure was tested with a gauge & computer tool and was confirmed OK.

Could this be a mechanical fault like engine wear due to running with low oil pressure, oil pump or / and the oil pressure control valve N428 ? The car at the moment is at an auto electrician for troubleshooting / checking wires etc.

Many thanks !

Stefan

error code:

5581 - Oil Pressure Switch 
          P164A 00 [036] - Implausible Signal
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 5
                    Mileage: 307591 km
                    Date: 2023.01.31
                    Time: 16:34:23

                    Engine speed: 0.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 77 °C
                    Intake air temperature: 20 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 11.920 V
                    Unlearning counter according OBD: 40
                    Crankshaft speed (RPM): 0.0 /min
                    Vehicle speed: 0.00 km/h
                    Vehicle voltage terminal 30: 11660 mV
                    Accelerator position: 0.00 %
                    C Eng Ds T u Raw: 2448.2 mV
                    Co Eng st: COENG_READY
                    Engine oil temperature: 11.0 °C