How to diagnose electrical issues for the rear controller...
 

Hello fabulous Porsche gurus :-)

I'm experiencing some puzzling issues with the electronics at the back of my 2013 Porsche Boxster S

Here is the evidence I can replicate right now:
- The center-rear lightning strip a foot above the license plate flickers randomly. (The type of patternless flicker that indicates electrical or electronic problems... I don't think the Porsche is 'trying to tell me anything')
- The trunk no longer opens (either through the bottom-of-door control or the FOB.
- The frunk no longer opens through the bottom-of-door control (but opens with the FOB)
- The spoiler is stuck in the up position and I can no longer bring it down.
- When I start the car I get a yellow 'system fault' (also saying car can be driven)

What happened is that I left the car for two months but because of a gap in the rear rooftop gasket, water managed to seep in during heavy rains and caused damage. Here is the evidence my neighbor reported back to me:
- The car's rear braking lights would flicker every 30 seconds or so.
- The spoiler went up by itself.
- The passenger footwell filled with about an inch of water.
- The battery drained dead.

I have not looked there yet but I believe that the trickle of water allowed through by the gap in the gasket made its way into some of the electronics that are a foot backward from the passenger's shoulders (either on the cabin-side of the rearward-side of the vertical structural wall separating the engine from the cabin)

Q1: Given the symptoms, which board do you think was affected by the water damage?
Q2: Would connecting my NT530 reveal more data about the system fault?
Q3: Would running a dehumidifier in the cabin a couple of days revert the problem?
Q4: Is there a way to 'save' boards like this by drying them in a warm oven?

Thank you so much for any clue you can offer!

Jean-Pierre

Electronics under the carpet under your seat(s) has likely been damaged or their connectors are wet/corroded.

Thank you for taking the time okei981. I'm going to try to locate this board (is it under the floor carpet?), see if I can dry and up or repair it. I've been looking for videos where someone does the procedure but so far no dice. Silly of Porsche to place electronics so low in a convertible car!

Update: I had kind of a scary experience taking a 30 min drive with my car as it continues to have electrical issues with the Rear Control Module... while I was driving I got a 'ghost in the machine' experience that seemed to alternate between two modes:

Mode 1:

- Getting a message saying the headlight control module was malfunctioning.
- Getting Engine Control Module not functioning errors.
- Getting various system faults

Mode 2: (Scary one!)

- All the instrumentation powering down as if the car was off
- The interior of the car being pitch dark (not a single light anywhere!)
- The wipers starting to run

The two modes would alternate every couple minutes or so.

My hunch is that the faulty rear control module is going haywire on the CAN bus... Do you think something might have gotten damaged by this evening's misfortune?

Tomorrow I will take the driver seat off, see where this damn module is, try to dry / clean off the connectors and see if I can 'bake' that board and save it... God I hate electrical problems like this!

Thoughts?

Hi JP.. I do agree, you do need to get the seat out and get to the faulty module. It is possible that a connector is "shorted" due to the water on it. That would be a best case. I do recommend you try to "dry" the offending module, but I think if it did get wet, then subsequent power, it is probably not going to respond.
Over the years, I have dealt with this, and have not had good luck reviving modules. When I found that I couldn't revive modules, I would open them to inspect, and usually the short is evident. I hope your luck is better than mine was. I have found situations where connectors were wet or corroded, and those had a more positive result.

Good luck. Keep us posted

Rich

I seem to remember that someone recently posted a link to access the 981 Shop Manual online. If anyone has that information, it might be helpful to the OP. Just a thought...

Hi Rich, thanks for taking the time and for your prior experience with these modules... I am befuddled as to why Porsche would place sensitive electronics at the lowest point in the cabin of a convertible car!

I will take the seat off to inspect the module, hopefully the damage occurred at the connector level. If not I will try to 'bake' the board in a warm oven to see if it improves. It was certainly a wake-up call to see how erratic the car's electronics were yesterday when that module started to affect others on the CAN bus. Will post as I gather more evidence.

Hi Terry, that would be super useful indeed! Lots to know about this module!

Link for the factory service manual in the post linked below.

water pump replacement - Rennlist - Porsche Discussion Forums

Thanks so much! Super helpful!!

Well I finally took out the Rear Control Module out and I think I'm looking at a disaster. Look at the state of my board!

Q1: Should I spend even one second trying to save this board?
Q2: The 'EcuDoctors' can only help up to Boxsters 987 (before 2013) as the 981 is now secured to the VIN
Q3: Can I obtain a used board and pay someone to program it to my VIN? (or must I buy new from Porsche and they have to program?) What should I budget?
Q4: Can I drive the vehicle with this board taken out? (Can it cause further problems?)

What a mess. Thanks for your advice and support everyone!
https://cimg9.ibsrv.net/gimg/rennlis...4d7d9c6623.jpg
https://cimg2.ibsrv.net/gimg/rennlis...b8d8033bcb.jpg
https://cimg6.ibsrv.net/gimg/rennlis...ddfc668942.jpg
https://cimg4.ibsrv.net/gimg/rennlis...612ed6b826.jpg

Hi again JP. i am sorry. I was afraid that is what I would see.. I can answer one of your questions, and don't waste a minute trying to revive that module. It simply will not respond.
At least now you know what was wrong.

Good luck.

That thing ran?!