Cayenne S 957 - Intermittent Wiper

[CayenneHater]

The rain sensor wiper operation (intermittent wipe) has stopped working on my Garbage Can 957 S | 78K miles. I have worked through all steps in the Owner's Manual and have not restored functionality. All other wiper-related functions are working.

 

Four rain sensitivity settings can be selected by rotating the barrel in the wiper stalk. Using my Durametric, I can see that each of the four rain sensitivity settings are detected. Likewise, I have verified with a Durametric the wiper stalk positions shown in the Owner's Manual (off, rain sensing, slow, fast, one-touch) are detected. So, the wiper stalk appears to be fully functional. 

 

When I move the wiper stalk to position 1, the wipers actuate once. Pouring water over the glass (rain sensor) does not actuate a wipe cycle regardless of wipe interval setting (1-4).

 

EXISTING FAULT CODES - Durametric report attached.

 

1.  Air Conditioning 3: Control Module Faulty
2. Gateway 0414 Control Module Coded Incorrectly
3. Vehicle Electrical System 1117 Load signal generator terminal DF - Implausible signal, test conditions are not-completed, fault is not currently active and is not causing a DTC light
4. Transfer Case 2025 Power supply - Open circuit/short circuit to B+, test conditions are not-completed, fault is not
   currently active and is not causing a DTC light
5. Tow Bar 576 Terminal 15 Implausible signal 

 

The car did not originally have a towing package. I installed a used towing hitch and towing module (scrap yard). The towing module has not been coded to the vehicle. I suspect that explains the Tow Bar 576 fault code. I also think that might explain the Gateway 0414. I might have also swapped out the HVAC controls for a better looking, similar unit which might explain the Air Conditioning fault code. All air conditioning / HVAC features seem to be working. 

 

QUESTIONS

 

1) Does anybody know how I can confirm/investigate rain sensor functionality using the Durametric? I have already verified the plug connection at the rain sensor.

 

2) Is there any control unit (relay) or other component that I should investigate to resolve the wiper problem? I've looked at wiring diagrams and I don't see a relay or other component, but wanted to confirm. [I am in the process of replacing a "Servotronic Control Unit" to hopefully restore power steering functionality during low speed/parking. This part appears to be a plug-and-play relay, but Porsche had a fancier description for that part.]

 

3) Any ideas on possible further troubleshooting?  

 

Thanks for any input!

 

 

durametric output.pdf