Hello AMHD!!

I own a 2003 Chrysler PT Cruiser. It is the GT model with the 2.4L Turbo engine. Lets get right down to it...

When I run the codes I get P1105 (Secondary vacuum sensor circuit).

No other codes pop up, the check engine light stays on, the car runs normal for the most part. There is an occasional shudder and RPM drop when the car is at idle and in gear but stopped. I attribute this to a dirty intake manifold sensor, I cleaned it a while back, will change it soon. No other problems with the vehicle's engine. I got the car at 104k and have put another 40k on it in the last couple of years. I am amazed by the fuel economy for this car. More than a decade old, and well used, a couple of weeks ago from Savannah, GA to Charolette, NC I got 27.5 ish mpg. Even through the mountains north of there I was staying above 20 mpg. It has plenty of power, seldom hesitates and starts in under 2 seconds every time. When I was up north and temperatures were near freezing it still started without hesitation, maybe taking a second or two more.

Anyway, its not the most urgent matter, and I assume it refers to a faulty sensor or a vacuum leak somewhere. All things considered, I have replaced many of the vacuum lines and all of the coolant lines and am working on other rubbers underneath as the Florida weather tends to be harsh on them. How would I identify the Secondary vacuum circuit in order to narrow down the issue? What does that circuit control? Any advise would be greatly appreciated.

Thanks in advanced guys.

P1105 is related to the TIP (Throttle Inlet Pressure) Solenoid and could indicate a problem with either the solenoid or the harness itself.
No matter, I would clean or replace the Mass Air Flow (MAF) as needed and also clean the throttle body and throttle plate as well. Then I would clear the DTC and do an extensive road test. You may need to do a couple of drive cycles (cold start to warm engine) before that code will reset, if it does.
Let us know...

On older Cruisers, it is usually a bad TIP Solenoid.

I never got around to fixing this until about a year ago, but txgreasemonkey, spot on, I pulled one of the vacuum sensors from a junker and it solved the issue. May have even got a little performance boost from the turbo. Credit where credit is due.

Thanks for the update. Now when someone sees what the fix actually was then we know it was a reliable one. It is all too often that we make recomendations and we dont actually know what the result was other then never hearing back and going on to assume it was fixed.