P0343 code - is it the DME?
 

Hi all,
It has been a while since I had a problem that was puzzling. My 2001 Boxster S suddenly developed a misfire and flashing CEL. I read the codes and found it is a P0343 code, indicating a probable wiring fault. I followed the recommended testing procedure and found 12V at the connector with ignition on but engine not running. Testing the wiring from the camshaft sensor connector to the other end of the disconnected harness at the DME showed no continuity. So far the testing indicates it's a short in the wiring that I need to correct.

Here's where it becomes somewhat less clear to me. With the harness disconnected from the DME, I checked for voltage on the DME output pin (on the DME itself). With the ignition on, there was 12V on pin 20. There was no voltage at pin 19 (camshaft position sensor 2).

Now I am confused because the wiring test indicates a short in the wiring but I read contradictory information whether it may be normal to find 12V at pin 20 on certain Boxsters or that the DME could have developed an internal fault.

The car has been owned by my brother or me since 2005. I know the wiring has never been hacked nor are there any add-ons to the car. I replaced the coolant reservoir and oil filler tube (on the engine) a week before the camshaft sensor fault appeared and moved the wiring harness out of the way while doing that job. So that makes it quite possible that a wire broke or chafed during that job.

I suppose the next step is to replace the shorted wire and see if it works. If anyone has experience with the issue, especially whether there may be 12V at pin 20 on the DME, I would appreciate the input. Apologies for the length, but I wanted to present as much relevant information as I can.

Thanks, Greg

P0343

CPS on bank 1, bank 1 is on the right side of the car. You need to measure on PIN C/12 which is on the third plug from top of the DME, see manual. If you look closely on the pugs they are numbered.http://986forum.com/forums/uploads02/c121784192863.jpg

Thanks for your reply. My car is a 2001 US-spec version with the DME 7.2. The pins for the CPS are different from a 7.8.

OK, probably Tiptronic?

But in any case you can follow this procedere to analyze it if you know your pins.

Thanks for that link. That's very helpful and more detailed than what I found in the Bentley manual. My car is a 6-speed manual.