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I had my 991.1 shipped back to the East Coast last week as I am taking a cross country trip back West in a few weeks. My son received the car and it was running perfectly prior and the last time he drove it. He cleaned the car this weekend and when I went to start up the car, I immediately got two faults pop up, something I have never experienced before.
One fault came up as ‘FAULT OF HEADLIGHT CONTROL SYTEM’ and the other was ‘PASM FAULT…possible to drive on safely’. I am running the DSC v3 Suspension Control Module and because of the fault , the suspension has defaulted to ‘stiff’ and the SPORT, SPORT+, PASM and TRACTION CONTROL buttons do not work. I am only allowed to drive on NORMAL MODE.
Not sure what has happened and not sure where to turn to as I am traveling. I am going to order a scanner to help but i’ m looking for any advice. Not sure if I can reboot the DSC controller to help. Maybe Tom @ TPC will chime in.
Thanks for the help in advance. Not the way I wanted to start a long trip.
A bit more information just came about. After I penned the above post, I took my wife to the store no more than 10 minutes away and after I dropped her off I went into the parking lot to investigate further. I stopped and looked down at the MFD and the 2 fault notifications were gone. I immediately hit the SPORT button and it worked. Strange!
I shut the car off and restarted and both faults appeared.
The drive earlier this morning was 30 minutes or so and that didn’t help.
My question is how does the car clear the faults itself and why didn’t they stay cleared?
I ordered a Foxwell Porsche scanner for tomorrow to help on this end. Any guidance is appreciated.
Thanks
Tom
I could be totally wrong, but my money is on the battery being the culprit, especially if it's the original from when the car was built!
Lots of us find strange electrical gremlins popping up in these cars as the battery starts to get older.
Is there a way to tell the age of the battery? I’m not at odds with replacing as I have a 4K mile trip ahead of me in the coming month.
Do I need a dealer to replace the battery or can I code a new one with the Foxwell scanner? (Haven’t read the instructions yet as I just ordered it!!)
What is the best battery to purchase for these cars?
Update once again.....When my wife was finished at the store, I restarted the car ,and low and behold, both faults reappeared. I drive for 10-15 minutes and as I was driving the faults cleared once again and all systems were GO!
Ran it that way for the next hour or so but did notice that I was charging at 14.5 volts the whole time where it usually drops to 13.8 after that long.
Installed battery is and Interstate MTX-94R/H7 and the date code was not punched so I can't verify the actual age. Faults definitely seem to be battery related as they disappear and I don't ever remember taking that long to charge to the standby state of 13.8.
Do I need to hook up a battery tender when changing or is this a precaution? Searching for batteries locally now..........
Had my local dealer install and program $326 total
OK, here's the latest on my saga........Replaced the battery with a Duracell SLI49ACM Premium battery about an hour ago. As I couldn't verify the actual age of the Interstate battery installed in the car when purchased, replacing the battery before a cross country trip was a 'no brainer' just as a precaution. After we replaced the battery, the faults still appeared ONLY at start-up. We drove the car for about 10-15 minutes and all of the sudden, faults go away and the SPORT mode and all other buttons work fine. Faults will NOT reoccur after they go away as long as you are driving or the car stays on. We did have a few stops where we stopped hard, shut the car off, restarted and the faults didn't appear, Can't duplicate this scenario each time.
There seems to be a debate on whether the battery needs coded to the car or not and not sure if this becomes part of the overall issue. I have a Foxwell scanner coming in the morning so I can dig a bit deeper if required and also recode battery if needed. We have had it out a few times and each time we restart we have the faults.
I am open to any suggestions at this time.
Final update on my PASM issue............After inspecting all systems at the dealer, Sewickley Porsche in Pittsburgh, the fault was being thrown from the DSC Sport PASM control unit that I had upgraded to back in December. The headlight control fault is thrown at the same time because the headlight control module has lost communication with the PASM control, the DSC Controller in my case, and can't adjust the headlights based on the suspension attitude. Makes perfect sense.
I immediately contacted DSC support while at the dealership and when I returned home we tried to just re-flash the DSC Controller with the latest firmware and config files. We had an issue with the connection process so DSC support sent out a new replacement controller for me to install. Out with the old and in with the new, problem solved, good as new and works perfectly. From the stellar service received at Sewickley Porsche in Pittsburgh to the awesome tech support at DSC, I couldn't be a more happy Porsche owner!
The battery may not have been the issue afterall but since I had no idea of the age/health of the battery, it was money well spent to assure me of a safe start to my cross country trip.
Kudos to the Sewickley Porsche Team led by Service Manager Duane Smith and Jeremy at DSC Tech Support.............you guys rock!
06-02-2021, 12:30 PM
PASM Fault from nowhere
