2008 Cayenne S oil monitoring failure

[GlenC]

Suddenly the other day while rolling to a stop, the warning message "oil pressure monitoring system failure" appeared... As I increased speed it dissapeared till I slowed again.... Since oil change was due (80K), I changed the oil (0w40 M1) and filter. I disconnected the oil pressure sending unit and reconnected (no easy task) ... took the car for a test drive and all seemed fine... after about 10 minutes of driving, the warning returned, but only when the RPM dropped below 1000. The "oil pressure too low" red warning also intermittently appears. While driving further, the RPM trigger point rose to about 1500RPM. The warnings all go away as soon as the RPM increases and only reappears when the RPM drops below the trigger point...

My Durametric software is malfunctioning, it will not return actual values. When they get it fixed, I will check the info coming from the sending unit to see if the signal is erratic.

If the sending unit need replacement, I'm not looking forward to the cost (~$170) and work getting to it. Looks like the cooling fan needs to be removed to be able to reach it.

Anyone else have anything similar?

Glen

[bigbuzuki]

Is the oil pump doing its job?

[GlenC]

Is the oil pump doing its job?

I think so, it runs for a while before the warning appears. If it were truly mechanical, like the oil pump, it would not be intermittent or delayed.

[GlenC]

Okay, found a copy of the Durametric 6.1.1.3 software, and it works and reports actual values.

The oil pressure is approximately 2300mbar at idle, 640RPM (oil temp 70C) and 4200mbar to 4400mbar at 2500RPM

Oil pressure reading is a bit eratic as well as voltage for oil pressure. Again, the problem doesnt arise for a while... I'll have to take it on a test drive again with the monitor attached and watch/record the errors when they happen. From the surface, seems like the sending unit!

[GlenC]

Problem fixed!!! YEA!... Turned out to be the pressure sending unit... Once I reinstalled the working Durametric, I did a road test while monitoring Oil Temp, Oil Pressure and Oil Pressure sender voltages. All was normal until the oil temp rose above 80C then things started to happen. Very erratic pressures and voltages, and when RPM was near 1000, all pressure sending stopped at something around .360V and something under 600mbar..... thus the deduction of sending unit failure. Ordered the sending unit from the local Dealer (got a good price!!! :-) ) and about 3-hours of work I replaced it (not the easiest thing to get to).....however, no more errors!!!

[Zigsevig]

Im having the same issue now .. how did you get at the sensor??

[GlenC]

It's been so long ago, I forgot I even did this....  As I recall, I had to take off passenger side air flow sensor and the intake pipe, the loosen the belt then a very tight space to get at the sensor.  Sorry I don't remember more.   

[phil nickisson]

Where are the actual values for the oil pressure on the Durametric