Burnt McGurnt

2010 GTS w/ 80kmi
I replaced a leaking dead battery about 3 months ago. Could my cell phone charger be draining the battery while parked? It seems that time is the culprit. After a 10 min drive the battery has enough charge to start. Only after sitting for about a week does it have trouble turning over and need a jump. The alternator seems to be working at 14-14.5 volts per the dash display when running.

I know these things get screwy and throw all kinds of codes at low charge. The PCM touchscreen just failed, perhaps from low voltage? See my previous post about misfire CELs and please chime in if you think they are related. I think I have a few separate issues going simultaneously.

Thanks for your input.

tomhartzell

If you don't routinely put your GTS on a battery maintainer for extended periods -- from CTEK or Porsche -- I would highly recommend investing in one. I put both my cars on a CTEK maintainer if I know I'm not going to be using them for 3 days or more. Your cell phone charger may be part of the problem if it's plugged in the entire time. (And when your battery gets low or is going bad, all kind of strange trouble codes will start showing up.)

ScootCherHienie

There is a 90% chance your problem is blocked roof drains. When the water can't get out the tubes that drain onto the ground, it backs up until it starts running down interior body panels where you never see it and gets under the carpet without making the carpet wet. Wiring harnesses are under there and splices that are not water-tight can have a resistance to ground that drains the battery over 5 to 15 days to the point the vehicle may not start or just barely starts. There is plenty of information about cleaning roof drains in the DIY section here. Usually, you don't have to do anything other than pull the little cover/cap of the end of each hose and let the water and grit out... job done, repeat for each roof drain outlet. It can take a LONG time for the moisture under the carpet to dry out in winter, but leaving windows open to allow as much low humidity air as possible to get in may eventually dry the padding under the carpet. It took 3 days of 100 degree temps with all 4 doors open in dry climate to dry mine completely. Water can collect in the well in the cargo compartment where the subwoofer and subwoofer amplifier are located often destroying them. It can also collect in front or rear seat foot wells. You can't tell if the padding is wet underneath by feeling the carpet. You have to lift the carpet and feel the padding underneath. Photos and locations of the outlets should be in the DIY roof drain info that's part of this Cayenne forum. Several issues that seem unrelated is fairly common when water has gotten under the carpet... sounds like your situation.

Petza914

I think your problems are battery related and that it is the cell phone charger depleting the battery when parked. As mentioned, invest in a Battery Maintainer of your choice and just plug the car in when you park it. See if your issues go away. I keep all my Porsches on Battery Tenders when they're parked. The battery in my 914 lasted 12 years. The 2 in my 997s are and at 6 and 7 years.

Burnt McGurnt

Thanks all.

I preemptively cleared my roof drains about a year ago but will check the padding for moisture now.

I will be disconnecting the cell phone charger from now on when parked.

I'm fairly certain one or both sides AOS are going bad. Should the engine start stumbling when removing the oil cap?

What side is which bank? how are the cylinders numbered? porsche noob here

Is there a factory service manual or the like somewhere for sale? I haven't seen one.

Thanks again

Petza914

If the AOS is failing it should be very difficult to remove the oil cap. If it's relatively easy to remove, yes opening it will cause a vacuum leak that will change the way the engine is running, so that's relatively normal.

deilenberger

The cylinders are numbered front to back..

As far as a factory service manual - there are PDF copies of a 955 manual floating around. Marginal usefulness IMHO since they're 11,000 pages - each procedure is outlined for each model, meaning if screwing on the cap on a valve stem is documented, it's repeated about 12 times for all the different Cayenne variants. There are enough differences between the 955 and 957 models that it may be of no use at all, depending on what you're seeking.

Perhaps more useful might be alldataDIY.com - around $18/year, it condenses the factory into searchable format and eliminates all the duplication. If it covers your year Cayenne I suspect you'll be happy with it. I have no experience with the 957 coverage since I don't own one, it's excellent on my '11 CTT and '09 Boxster. We'd be interested if you do try it out on how you find it - useful or not?

Petza914

I believe as a rule at least within Porsche, Bank 1 is the bank that has the #1 cylinder on it. For LHD in the US, that means for my Cayenne that's the PS, for my 997 it's the DS, and for my 928 it's the PS. The 997 is essentially different because it's a rear engine so the motor sits in it backwards (crank pulley on the side toward the back of the car instead of toward the front).

thesteve

Do you have a second battery in the rear? Before I changed mine (2nd batt in rear) I had the problems you speak of despite a new main battery, because the bad battery hogs all of the normal charging current while driving.
Forgive me if that's not an option in the 2010 GTS, I have no clue.
BTW, through the whole pandemic, with barely driving my car, I've never had a dead battery. But I have two good batteries now. (pre-pandemic, and before I replaced my bad rear batt, I was always SOL after letting the car sit 2 or 3 weeks.)
That said, I think I did kill my main battery once recently after leaving my charger plugged in for a week. But it may have been my Garmin GPS.
Lesson learned either way, I unplug stuff from my cig lighter now that I'm working from home.

Burnt McGurnt

Second battery? I dont think so.

barrios35

My PCM was draining my battery. I pulled it out and battery was good. Replaced it with an aftermarket and never looked back. Best decision ever.

ScootCherHienie

99% of un-obvious battery discharge problems are caused by the caps on the ends of the roof drains getting plugged with dirt. They trap bits of road grit and over time, they stop draining the runoff from the roof. When that happens, water finds its way to the lowest point in the car by traveling down body panels behind the trim where you never see the water draining into the interior. It does NOT make the carpet wet. Instead, the water goes all the way down to the metal floor and gets absorbed into the padding under the carpet. Wiring harnesses pass back and forth under the carpet padding and connectors and splices in wires eventually get wet and voltage from the electrical system gets slowly drained until the source of the moisture is removed and the carpet padding is dried-out. There's no actual "cleaning" of the drains required. Just find the roof drain info in the DIY section of this Cayenne forum and remove the caps from the drains. If water runs out when you remove one of the caps, that's the one that was leaking into the interior. A lot of people do not reinstall the caps as they don't really serve a useful purpose as the drains stay clear without the caps on them. The roof drains exit the body down low so you need to get under the car to find and remove the caps. I do not know if locations of the roof drains are the same for the small sunroof and the panoramic sun roof... when you get to the DIY section, see if there's any mention about whether the 2 different sunroof options share drain locations or not. You can't feel the water in the padding by pushing on the carpet, you have to lift the carpet, but it is tightly fit in a few places, like the kick panels in the driver and passenger footwells. People tend to experience periods of 4 to 10 days with wet padding under the carpet before the battery is discharged enough for the Cayenne to not start without a jump or battery charge. That said... don't leave chargers plugged-in. The way chargers SHOULD work is by turning off when there is no load on the charger (that may even be a law now), but I've seen enough weirdness in chargers to not assume that they turn off properly when there is no load (phone, etc.) connected.

Pepperman

i have this problem I did clean drains but still water is dripping on gear selector from the top lights console