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Miserable Fault Codes-Help

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I have a U.S. model 2006 C2S with 131,000 miles which has been running great despite my fault code woes that keep coming back intermittently or do not clear at all. Of particular concern are those related to the engine, but nevertheless I have included all fault codes here as some "may" affect others. I use a Durametric Pro unit. I can only clear the fault codes in #1, below. All the other fault codes cannot be cleared either individually or by choosing "clear all fault codes".

(1) Bosch Digital Electronics Motronic 7.8.1

P0420, Catalyst system efficiency below threshhold bank 1

P2099, Post catalyst fuel trim system too rich Bank 2

P2097, Post catalyst fuel trim system to rich Bank 1.

 Initially I had just lean as opposed to rich conditions in bank 1. As a result I replaced  all four O2 sensors and leaking throttle body. Smoke test done with no leaks indicated. I now get these three fault codes if I drive the car about 150 miles. Sort drives do not seem to trigger fault codes. I have rechecked all the electrical connections to the O22 sensors several times. I am wondering if this is not a catalyst converter issue. Thoughts please before I spend money.

(2) Vehicle Electrical System

Current Fault Codes

8039, Filler flap actuating element

The local dealer told me that this is a common problem with the 997 and they don’t even bother to fix anymore unless the customer insists. In my case the spring  solenoid/actuator  can be pressed in and bounces back but not enough to catch the flap. I’m not worried about this fault and only mention it just in case it is somehow connected to any other issue mentioned in this post.

(3) Airbag -POSIP

Current fault codes

C152, Communication PSM control unit (drive)

I have no idea what this means. would appreciate explanation and advice.

(4) Advanced Weight System-AWS

Current Fault System

8014, POSIP LN no communication

I checked the yellow contacts under the passenger seat and they are plugged in properly and are secure. Does this issue affect the airbags? Any thoughts would be appreciated.

(5) Porsche Access System-PAS

Current Fault Codes

8004, Terminal 50

What does the PAS really do and what is terminal 50? I do not get a chirp when I lock the car.

(6) Front Body Module

Current Fault Codes

8028, Left fog light

8029, right fog light

8042, Front luggage compartment unlocking

The fog light issues are my own doing as I have done a hack for my after market fog lights that are used as DLR’s with the switch in the Home position and pulled out to the front fog light position. I have no idea about the front luggage compartment unlocking as the lid lock works as it should with both the key and the latch in the door sill.

(7) Air Conditioning

Current Fault Codes

8035, interior sensor fan

A/C works fine. Where is the sensor fan located?


Any and all help and suggestions would be most welcome.

Thanks in advance.



Edited by Uwon
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Let's start with the most obvious first: P0420 (or 0430 for the other bank) is a three-way main cat efficiency failure, if the two O2 sensors on bank 1 are reading correctly electrically, the OBD II manual recommends clearing the code, road testing the car, and checking to see if the code is back.  If it is, the cat is on the way out.


POIS: This is Porsche Side Impact Protecting system, or side airbags. One of your codes indicates a lack of communication in the system, which could just be a control module reset or replacement, which is going to require a PIWIS system. It could also be a simple wiring issue.


PAS: Porsche Active Safe, or PAS, is an advanced driver safety system designed to limit forward collisions by using a powerful front-facing radar scanner to detect other vehicles. You would need a wiring diagram to determine what terminal 50 is, but 8004 is a PCM/Radio code - that says the CAN bus is not connected.

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JFP, thank you for your quick and informative reply. Lots to take in.
 About the cat converter, what is their usual life span on these cars?

Do you have a positive opinion on any of the various after market cats, such as Soul, Magna Flow, Fabspeed, etc.? I’m more interested in reliability as opposed to noisier exhaust.




Edited by Uwon
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Asking what a cat life span should be is like asking "how high is up".  Multiple factors come into play, type of fuel use, quality of fuel used, how the car is driven, oil consumption levels. etc., etc.  The factory cats were warrantied (thanks to the EPA) for eight years or eighty thousand miles. 


Only problems we have seen in aftermarket cats are performance consistency and build quality, so if you want a long-life unit, go factory.

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