I have an `06 3 with the 2.0 and an AT. First thing is the car won`t start in park. The "P" does not light up on the dash gear indicator. I have read that since this is not lighting the car does not think it is in park and therefore wont start. The only way the car will start is to put it in nuetral. Needless to say this is getting old real quick. I have taken the center console out and looked at the shifter. There are no visual problems, shifter moves back and forth without any obstructions. The tiny plunger that gets pushed in when in park is being pushed in. Any thoughts???
The second problem is the CEL has come on and off a couple of times. There are 2 codes coming up P0455 and P0171. P0455 is primarily a loose gas cap code, or a major evap system leak. I have checked from front to rear on the system and I see no cracks or loose hoses. Can a gas cap go bad or be intermittently bad? For code P0171 I removed the MAF sensor and cleaned it and tightened the fittings around the air-box. Any help would be appreciated.
Also, does anyone make a shop manual for this car yet?

 

The ECU/PCM controls both and my guess, which is actually a pretty standard one, is that it needs resetting... or at least it won"t hurt to try it.
Also, have you tried connecting the wires on the "plunger" together to see if it starts in Park? A better way to tell (re: safer) would be a VOM (volt-ohm meter) to check and see if the switch contacts are making contact w/each other, or disconnecting, as the case may be.

 

I have cleared the codes and they return after a run cycle.
I haven`t tried to mess with the plunger or the wires that connect them. I am going to try next to see if power is coming in or out of them. Do these cars have a nuetral switch? When I had this problem on some of my older cars it was a nuetral safety switch.

 

You wont get much, if any, power through your switch. You need to check for continuity. (The fact that the circuit is making a complete loop)

 

Agreed!It"s very low voltage/current.
Look for connection in the switch itself.
Disconnect it (and the battery first) from the main harness and check (Ohm setting) to make sure that it is acting like a switch.
BTW: AndI am far from an expert on the ATX trans, but I would think that they do not have a neutral switch like a std mechanically shifted ATX. It seems nearly everything about themis controlled electronically, through the ECU.

 

I third that it's most likely the micro switch that's gone bad.