My 2001 S has started throwing check engine codes occasionally when the elevation drops my 1500-2000 ft (I live in the mountains). Specifically the P0442 Porsche code 97 minor leak in evaporation system.
The question therefore is this real or as a result of the car deciding to run the evap check just as there is a 5% change in atmospheric pressure. Significantly, this happened today right around a drop and the fuel level dropping below 3/4. I believe that can trigger the evap check to occur.
From what I can understand of the way the vacuum check works, a rapid change in ambient pressure would be exactly the thing the computer would see as a minor fault.
The forum search is not working for me (ticket has expired), but searching around, the usual culprits in order of frequency to throw this fault are, gas cap, vent valve, purge valve. However diagnosing the system is stated to be tricky even for a pro with the correct gear.
Thoughts? Will the fault clear after three engine start cycles or will I have to clear it with the reader each time? Should I start with the R&R the parts in order, or is this one for the pros? Alternatively, did the engineers just not think through this driving scenario and are all 986s prone to this when in the mountains?
Many thanks
Philip
Linear Mode
