Using a OBDII Code Reader

[Porsche_Joe]

My engine check light is on so I connected an OBDII code reader and I have a code of P1123. Does this correspond with DTC 123 in the shop manual?

DTC 123 is the dual engine temperature sensor. One part of the sensor operates the dash temperature gauge and the second part feeds temperature information to the DME to help adjust the fuel mixture during warm up. This second function corresponds to my symptom. The CE light will only come on as the car nears normal operating temperature and it has to be idling (usually stuck in traffic). If I am able to avoid idling during this particular part of the warm up cycle then I never see the light.

I checked the sensor with an ohmmeter. It read a higher resistance when cold than the factory spec but about right with the engine at normal operating temperature. I want to make sure I am on the right track before I replace the sensor. Any information you can provide will be greatly appreciated.

[Loren]

There are two Boxster TSBs that mention a P1123 fault. One has to do with water in the air cleaner and the other one has to do with a cracked or leaking oil filler hose. If you want a copy of these TSBs then PM me your private email address.

[craig(nj)]

I checked the factory Boxster OBD II manuals and for P1123, theysay to check the fuel pressure regulator, and fuel pressure.

[Tool Pants]

Is that Joe King?

I also have the OBDII diagnostic manual and Craig is correct. P1123 is for cylinders 1-3, and P1125 is cylinders 4-6.

The sensors are detecting a rich condition. Like Craig said, the fuel pressure is too high or there is a leaking fuel injector, is what is listed as the fault area.

Hope that helps. Jeff

[Porsche_Joe]

Yes, Porsche_Joe is Joe King. I have the the 15 volume Porsche Boxster Shop Manual. There are a couple of diagnostic volumes but I have yet to find a cross reference to convert a P1123 to a DTC 27 which is the way it is listed in these manuals. Do you have the part number for the OBDII manual and does it have a cross references to provide the conversion from PXXX to DTC XX? Maybe I am missing something in my shop manuals. Thanks!

Thanks

[craig(nj)]

Boxster OBD II Manual part # WKD 483 620