Coolant Display Defective
 

I have been seeing this pop up with consistency at inconsistent times. Prior to its appearing I KNOW the engine coolant temp is normal. If I turn off the ignition and restart, it returns to normal functioning. My intuition says it's one of the two sensors that are bad but several people proclaim removal and replacement of the thermostat (and therefore water pump) are necessary. This does not make any sense to me, as I mentioned, the temperature was normal before and after I restart. What say you?http://forums.pelicanparts.com/uploa...1673029685.jpg

Your photo shows you are cruising along at 64mph (warmed up?) and the coolant gauge ("coolant display") needle is not showing any temp.

Bad gauge? Bad gauge connection?

I'm impressed with Porsche's sensing of the sensors, so I would expect that starting with what is called out first makes sense.

More information...the temperature is always normal (say 130-150deg) when the warning appears. This is what I meant when I stated that turning the engine off and turning it one again results in a normal reading. The engine is warm at this point, but the timing and temperature at which it occurs is inconsistent.

Did you look up the fault code?

From Rennlist, it’s just low coolant, fill it up and see.

So, I had the two temperature sensors replaced for a tidy sum and it did not fix the problem. The next suggestion was to replace the thermostat, which necessitates removal and therefore replacement of the water pump. Does anyone have any idea as to why changing of the thermostat would fix a problem like this? The engine coolant temperature is not abnormal when he fault occurs.

Did you check the coolant level?

It could be the level sensor, I would not be changing the thermostat unless it's overheating.

The coolant level is normal. The fault code is P 3081. I think the answer lies in the fact that the cayenne thermostat is an active one and has its own sensor that is being read by the computer and checking against the oil temp.

I assume you’ve read this:

https://www.autoserviceprofessional.com/articles/9690-faulty-porsche-coolant-temperature

I just had that forwarded to me by my shop owner that did the research to find it. He is trying to see if Porsche released a TSB on this issue. I will let everyone know if this works. Thank you for your response.

So..there is no TSB for this problem with this vehicle (there is for the hybrid), but there is a solution. I finally decided to follow the advice to replace the thermostat (which included the water pump and the serpentine belt). This appears to have solved the problem. I was not initially aware, that the thermostat itself has a sensor in it (as is is an 'active' thermostat). I did the work myself. It was an all day job, greatly assisted by Youtube university...

Thanks for the follow-up, let’s hope you got it.