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highly likely; probably fastest way to tell is to pop an ammeter across the connectors to see if current is applied to the actuator, if it is then its got to
be a vacuum problem ...
Can you edumacate me on change over valves? I thought that the valve would be driven by the vacuum (similar to a pneumatic valve) and that electricity wasn't involved. But then I guess the term "change over refers to electricity to vacuum - maybe?
For a bit of reference regarding the vacuum lines, I posted a DIY some time back on 6Speed... And on my blog.... 991 Exhaust Sound Hack
You don't have to remove the rear bumper cover to reach the two connections to the exhaust flaps... but the driver-side valve is tough to get to on the S exhaust.
Simply pulling the vacuum line from the exhaust flap valves will leave them either open or closed. In most cases owners who have had the Change-Over Valve failure the flaps could be in either position. Others have experienced a loose vacuum line which leaves the valves in "loud" mode. And then there's people like me who purposefully pull the line off, and cap it to kill the fault message.
Do some searching on the forums for COV issues. There are some really good technical explanations and diagrams available to help you understand how they work, when, and so on.
Location of all the COV valves. Including the vacuum lines to the PSE / S exhaust flappers.
I googled change over valves and answered my own question.
So why go to the trouble to use a vacuum to drive a diaphragm to move a rod in a linear fashion rather than just using a linear servo? Sorry this is OT, feel free to dismiss.
For a bit of reference regarding the vacuum lines, I posted a DIY some time back on 6Speed... And on my blog.... 991 Exhaust Sound Hack
You don't have to remove the rear bumper cover to reach the two connections to the exhaust flaps... but the driver-side valve is tough to get to on the S exhaust.
Simply pulling the vacuum line from the exhaust flap valves will leave them either open or closed. In most cases owners who have had the Change-Over Valve failure the flaps could be in either position. Others have experienced a loose vacuum line which leaves the valves in "loud" mode. And then there's people like me who purposefully pull the line off, and cap it to kill the fault message.
Do some searching on the forums for COV issues. There are some really good technical explanations and diagrams available to help you understand how they work, when, and so on.
Location of all the COV valves. Including the vacuum lines to the PSE / S exhaust flappers.
What's the point of this? Sport mode without the noise?
Throttle response is a lot sharper in Sport mode, and for PDK cars, the shift points are more aggressive (if still too sluggish.)
There was never any good reason for Porsche to associate the Sport and PSE functions with each other. I use a microcontroller on the LIN bus to maintain the state of all of the buttons independently across drive cycles, and I've found that my usual personal "default" is Sport on, PSE off, PASM off. When I'm in the mood to shift manually I turn Sport+, PSE, and PASM on for the whole "experience," but otherwise PSE usually stays off.
Conversely, the only time I turn Sport mode off is when I'm stuck in traffic, where the lazy throttle response and early shift points can be more relaxing.
I've seen this happen on a couple cars, most of the times the valves themselves have gone bad and need to be replaced. I wouldn't be surprised if this has happened again to your car.
One of my friends had the vacuum line to his exhaust come loose, and the car threw a coolant line warning.
Yep, it just means that I don't have to hit Sport and/or PSE every time I start the car. It's a minor tweak for the current cars, but will be a bigger deal in the next generation where you won't be able to disable auto start-stop by default.
Zapta's little hack will be very popular with the 982s and 991.2s, I suspect.
02-05-2016, 05:25 PM
Vacuum solenoid had failed. Thanks everyone