@Schwinn good point, I'll see how hot things are this weekend, we've been in the 90s lately so may not be necessary anyway.

I already replaced the rear control module, per the OP that had originally fixed everything except my remote key unlock and the top control. I considered wrapping the whole thing in electrical tap to seal it up lol - I'll keep an eye on that waterproof case...

@b3freak - just heard back from Porsche, my dealer claims they're all the same. When asked if the security module is the same as the rear control, under the driver seat (US cars), they replied "It's the same one. I think I called [it] the security module. My techs call it the alarm control unit. but it's all the same." I really have no basis to say who is right, but now I'm a bit worried they reprogrammed the wrong module and even if I sort out the new problems my old problems will still need addressing. Can you confirm where the security module you're referring to would be located? Maybe I can just find it in my car. I went to the parts site you linked but didn't see any modules referencing "security" or "alarm" control.

 

My question to them would be... "If you successfully reprogrammed the "security module", then why can't I remotely gain access with the Keyfobs?"

I wouldn't have left the dealership without at least programmed keys. Seems like they charged you for a whole lot of nothing especially since they couldn't give you a diagnosis on the rear deck lid not working.

My thoughts are this... if the so called "rear control module" and the "security module" (Anti-Theft Alarm Control Unit if you prefer) are one and the same, then why two part numbers?


Here is another site. I began the search for a 2010 Porsche Boxster -
http://www.autoatlanta.com/porsche-p...section=901-04

It's called "Control Unit Porsche Access System" at AutoAtlanta and "Anti-Theft Control Unit" by Porsche of Atlanta
https://www.porscheatlantaperimeterp...category=20117


I can't be 100% on your car, but it seems like I read someplace that Porsche was going to move the module to a better location because of this problem with water ingress, but again, I can't be 100%. I'll check my car when I have some time.

 

Eric,

Read this thread...

I could be right in that Porsche decided to move the security module to better location.

https://www.planet-9.com/threads/m-5...cation.247677/

 

Eric,

Just got under the car. My 987 security module is located next to the steering column. Not easy to access, but doable.

ECU doctors call it an "immobilizer" which is actually just one function of the security module. Here is removal instructions from ECU doctors.

 

Thanks for all the extra research, I’ll see if I can find that on my car when I get back to all this this weekend. I’ll also call Porsche back tomorrow to see what’s going on here… when I first picked up the car they only mentioned the top not working, so when they gave me the keys and I signed for the work I was expecting the keys worked. When I walked out to the lot to drive off I noticed the keys didn’t work, so I did go back in to ask. They just chalked it up as indication of additional issues from the water, and said I’d have to pay more for them to look into it. Thinking I had still gained something with the top at least trying, I didn’t complain. In hind sight maybe that would’ve saved me a lot of hassle.

 

Eric, I found the procedure for reprogramming or correcting key issues with the 987 in the shop manual. I'm not trying to step on anyone's toes and so it's best to work with the dealer's tech team or other authorized shop that has access to the PIWIS and Porsche service network. According to the manual, the module that handles the security/immobilization/access to the car and programming of keys is called the KESSY/PAS control unit. And, based on the diagram it is definitely located behind the steering column. (see picture) Even though it's located in a better area than in previous Porsche Boxsters (i.e. under the seat), this unit still can get damaged if exposure to high levels of moisture or water ingress which usually happens from the water trailing down the a-pillar and flooding the floorboard. Maybe the actual tech working on your car was concentrating on the getting the convertible to work and didn't really think about the key issue? Maybe a little miscommunication to the service advisor? Anyway, it's still my opinion, that the security module (KESSY/PAS control unit) is the one that is in question. Have you tried relearning your keys? Sometimes that works! Anyway, all the best! Hope it works out.

 

Hey @b3freak ,

Thanks again for the research, I do remember seeing a module down there when I was originally messing with the brake pedal switch, and can confirm it was bone dry under there. I'll try to find some time to pull it and inspect closer, but finding time to work on this has been difficult. I'll keep doing what I can on weekends. I'll call Porsche again Monday to see if they can comment more specifically on that module / why the keys may not have been programmed, but it feels like my Porsche dealer is pretty checked out on this now unless I pay for a re-inspection. I may give into that eventually, but not quite yet.

Best,
-Eric

 

Sounds good Eric, just trying to help.

My advice at this point is to put out these fires out one at a time. Don't get overwhelmed or discouraged. How do you eat an elephant? ANSWER: One bite at a time!

Now, as a side note, since you unplugged the battery from the car and let it sit overnight, it might have to relearn itself... or complete a drive cycle for it to correct rough running. I recommend taking it for short 30 minute drives near your home. It may take several trips to complete the drive cycle and provide a "readiness status". This can be shown in a proper scan tool that provides live data. You need to establish if water has affected the engine in some ways. It's not uncommon that wet coil packs will cause misfires and a CEL. The DTC will be P0300 to P0306.

Keep us updated! All the best!!!

 

So I got some time to dig in a bit today. First update is the engine completely sputters out now - starts after a few seconds of cranking, runs uneasily for a few seconds, then stalls. This is running at idle, not pressing the accelerator or engaging any gears. So I first double checked the battery, it’s a 2019, but I put it on a charger for a while anyway to be sure it’s topped up, and it holds steady charge while cranking so I’m confident that’s not the issue.

Started looking into the fuel pump, you can hear it running for a bit just after the car stalls so it seems likely that it’s going bad or at least the relay to control it may be. I pulled the relay plate first since that’s the cheaper possible solution, but I’m unsure which relay goes where. I found the attached chart which seems to be the right layout, but slightly differs from what I have. Also I read online the fuel pump relay is supposed to be in position 8, but my position 8 is blank… I’m going to keep looking to see if there’s another part label but figured I’d post first in case someone knows off hand which is the right relay.

Photos attached…

 

I’m too lazy to read the while tread, but based on your first post the first suspect is HPFP. Before you replace it - you need to connect the scanner and check the live data for HPFP. There are 2 parameters that should interest you - set pressure (that system asks a pump to provide) and actual pressure (that pump is providing).
But the trick is, if the pressure is lower, the culprit may be the pump in your tank that doesn’t supply pressure or volume to HPFP. So you also need to measure it using a fuel pressure gauge (I guess there are no sensors for it to see it on the scanner live data).
The pressure for those both pumps should be tested in different driving mods (idle, cruising and hard acceleration too).
But based on your description when it’s getting worse and worse- I would speculate it’s HPFP.

I made a few DIY videos about my Cayenne, but it’s the same thing in your case.

 

I don't have a list of which relay is which, but the fuel pump relay should be powered by fuse D1 and should have three red/blue wires attached to it and one green/black wire attached to it. That might help you figure out which is which.

 

Eric, are you sure you want to jump problems? It's easy to chase rabbits down holes, but seems like the repairing the immobilizer and rear control modules should be the first fires to put out. Relays are pretty tough to kill unlike the modules under the seats that are in direct line of fire (or water in your case). Personally, I would make sure the DME and security modules are happy before moving to the rough running/stalling problems.

 

RCM has nothing to do with the engine running condition. You can start and drive the car without the rear control module at all. Immobilizer is not a suspect too - should it be a culprit - the vehicle won't start at all.
Only 2 things needs to be done is - test the fuel pressure from the low pressure pump (in the tank) and test the pressure from the high fuel pressure pump.
If all the fuel pressures will pass the test - then you can continue looking for other culprits.

 

Replacing the RCM was the first thing I did, which did seem to fix 90% of the initial issues, it just had to be coded to the car for the top and keys to work. All the engine issues started after the dealer coded the RCM (which didn't even fix the top or key issues). So I'm reasonably convinced based on our discussions about the RCM vs "Security Module", which was their name for supposedly the same module, that they may have programmed the wrong thing, but they're giving me the typical "the tech didn't notice anything weird" and that I have to pay more to reinspect.

For those joining in later, the car ran mostly fine when I picked it up aside from a slightly longer crank time that I attributed to battery drain (left a door open while servicing or whatever), so I didn't say anything until I was 3/4 of the way home in limp mode and couldn't reasonably drive back to the dealer. They attributed the top and keys still not working to "other issues caused by the water damage", which I felt was a reasonable answer at the time.

So I have to agree with HETPE3B on this one, the current issues don't seem to be explainable by RCM or immobilizer. I pulled all the carpets again to confirm everything is definitely dry, and both modules are working as far as I can tell (minus the top / keys). Brake lights, turn signals, spoiler control all work, the top just doesn't try at all. For immobilizer, not sure if it's all the same module (forgive me if I'm confusing terminology here) but the steering wheel lock never had issue, and the alarm doesn't go off entering the car manually anymore (which it used to with the fried RCM), so I think they're working properly? I'm certainly the newbie here so if there's still a compelling reason to look into the top / keys I'm open to anything, but at the moment I don't see how they could be related to the engine issues, and I would much rather a drivable car with top stuck down and manual keys than the pretty paper weight in my garage now :P

Thanks to everyone again for all the suggestions and help thus far, next step is I'm going to order a better OBD scanner (the Foxwell NT530 Schwinn suggested) and invest in the proper service manual - free info online has had mixed reliability.

-Eric

 

Have you tried to drive the car in order to complete a drive cycle as I suggested last week? Have you tried the process of relearning the keys?

Once you get the Foxwell, make sure you run a complete test of all modules it supports. Not just the generic OBD scan.

I look forward to seeing the results.

Cheers!