any updates? can you take pics of the supposed problem area?

 

actually, i'm taking it to the shop tomorrow to have them track down the electrical problem. it's about time i took advantage of my extended warranty. the change-over valve is what's being shorted out every time i replace it (there's a pic on the first page of the thread).

 

My guess is that the electrical control system (from the dash switch and DME) isn't working right, and is causing the solenoid to fail. Makes me wonder a little if the ground connection (wherever it is?) has a high resistance connection. Someone mentioned that the factory system actually keeps voltage on the power lead to the solenoid, and completes the circuit by connecting the ground lead to ground when you want loud mode. I don't know anything about the circuitry of the factory control system, so would do what you're doing: take it to the shop for diagnosis.

 

this certainly has the makings of a bad ground connection because, as of about 90 minutes ago, my problem is gone. i had to cancel my appointment since it's not happening anymore, but i seriously doubt this is the last time i'll see this. i'll have to see if i can track down the grounds on my own and shore them up.

 

this about sums it up.

 

There are main grounding points in the rear near the upper shock mounts. Suggest checking connections at these locations. This is photo of one of them in the rear of my cab. Note the brown ground wires connected under the ground nut.

 

thanks ken.

 

just a quick update to this. i've run 300+ miles and i'm still working. i came across an article in the PCA porsche magazine (see screenshots) that might actually explain part of my problem.

I did have to jumpstart my car recently because I let the battery run down, and just before my problem fixed itself, i checked some of the PSE cabling and disconnected and reconnected some of the DME connectors while trying to troubleshoot this. I had the battery unplugged for 45 min or so while i did this. I wonder if this simulated the handover procedure mentioned in the article? It still doesn't explain why disconnecting the solenoid had no effect on volume, but it's a start at least.

 

I'm having the same issue with my car (2007 C2S Cab). Voltage at solenoid is 14V on quit mode and 10V on Sport Mode. I think this is causing solenoid valve to go bad and get stuck on solenoid being open all the time, i.e., not loud.

 

I'm curious whether anybody else had this problem resolved. I have a 2007C4S and i have this 10V/14V thing as well. I recently replaced the solenoid and it worked fine for 100 miles or so. Then I got the rattling sound. I measured the voltage, and its the 10V/14V. If I unplug the hoses from the solenoid and connect and disconnect them to each other manually myself, everything works. So its probably some voltage issue busting the solenoid.

Any help would be appreciated.