Hi. I'm new to the saturn forum. I have owned my Saturn Sc2 since Oct. 2006, and needless to say I'm a Sattie freak. My question is my car drives fine in town, but when I get home and put it in park it will idle high, and i can put in other gears reverse, neutral, and others it will idle fine, just not in park. I have to turn the car off and then turn it back on and it idles fine. I'm thinking it might be the idle air control valve sensor. Any other ideals. Oh yea i have already replaced the EGR valve. Any information would be greatly appreciated. When i figure out how and get pictures updated I will post them and share. SUPER fun site!! Thank you. 99sattieSC2

 

Welcome to the forum. I am not that much of a tech so I can't be much help with your problem. But I'm sure somebody will be along with some answers.

 

According the theory of opeaton contained in my Mitchells service information is that the PCM the electronic control Gizmo that determins how the engine is going to run monitors a number of switches make that determination with. One of which is the Transmission Range Switch. This indicates what gear the transmission is in so that the PCM can determine the need for a given idle speed. As your problem starts when the transmission is moved from Reverse into Park. Reverse being the last place it was as the lever is moved to Park, it could be that the switch is creating a false input for that bit of information which either corrects itself via the action of starting starting the car or just takes that much more time for it to register correctly. Dunno, never though of it, can't remember ever really wanting to. But according to the theory guide, the logic thinks it is important enough to look for it.
So I too went looking for it, the service documentation said it was located on the rear of the transaxle. It was called the park/neutral switch. I found reference to it on page 4 of the wiring diagrams for the PCM. Assuming of course that pretty much all manuals are going to use the same diagram because it is available. If that is not true, than it is there some where. Obviously something mechanical has to actuate the switch to to make it work when the transmission is in park and neutral. That it works (if it is the problem) in neutral I would get suspicious of the mechanical part of it being out of adjustment or something for the park position.
Or as they say when you are not sure!
It is something else.
Good luck.

 

Thank you for the information on my sattie. I will give your information a try, and thanks also to all the other members helping. 99sattieSC2