Ragestar7

Hi there everybody, please excuse me for any rookie/ignorant behavior as I am new to the forums. I purchased a 2016 Porsche Cayenne CPO last year. Here is the problem I am having;

1. One day all of a sudden, the start/stop button does not deactivate. I always press it the first thing I get in the vehicle and it stopped working. The light does not pop up anymore. I searched a lot on the forums and I found many cases of START/STOP functionality as a whole not working, in my case it works, but im unable to DISABLE it. Did not find a single thread with my scenario.

2. Interestingly, if you press the Sport button, the start/stop button gets deactivated and the light pops up.

3. I do not want to keep driving on sport as I have a weekend beast reserved for that sort of driving, so I would like to fix that button.

4. Dealer states "two master technicians" suggest it has to do with the battery voltage, and suggests replacing the battery, he said battery is not covered in CPO and wants close to $900 for the replacement. I bought the car at 66k miles and in 8 months have put 8k miles, so I do not see the battery dying out? I do not know when it was last replaced, but my radar detector has always shown voltage to be above 14.5V.


5. I thought the battery should be replaced when the functionality of start/stop STOPS working, but in my case, I am trying to DEACTIVATE this system rather than ACTIVATING it (which it is by default for 958.2 cayennes)

6. Any input is appreciated! Also attached a photo of my Cayenne

GTCharlie

Batteries unleash numerous gremlins in this car so they're right to suspect the battery. One of the factors the car uses for start stop functionality is battery health. The life expectancy is 5 years so you're due anyway if it's original. I bought my '16 (9/15 build date) in 11/21 with 62k miles and the battery voltage didn't meet CPO spec so they replaced it. They date stamp the mfg date on top of the negative terminal if you want to go through the trouble of getting to it under the driver's seat. Parts and labor was $777.

By the way, The 958.2 Auto Start Stop can be turned off at startup with the defeat device by T-Design's. http://t-design9.com/memory_module_porsche.html

lacibaci

What happens when you program the Multi function key and use it to disable auto start?

Dr. G7

I would be unhappy if my start/stop button does not deactivate. I also hit this the first thing.

As other posters have mentioned, a weak battery could be the culprit.

~$1000 is steep. Can you get a reputable indy to look at it. A caveat: the battery replacement is not a simple job. But then, nothing is simple on a Porsche.

lml999

The battery in my '15 CS is original (at least none of the service paperwork lists a battery replacement.)

I figure seven years is pretty good; I just booked time with my indie to replace the battery and to finish programming my trailer module. I'll be in upstate NY and the Poconos (for Porsche Parade) in June and would prefer not to be dealing with a weak/dead battery while on the road...

Ragestar7

Hey guys, thank you for the quick replies, this was finally solved, attached is an image of what was wrong. BTW, good news is, I got a free battery replacement !

Ragestar7

Thanks for the reply mate! It was not the battery, but they decided to replace it as the first step in troubleshooting, and that did not solve the problem, so they could not charge me for it. .

Ragestar7

I just got the car back, I never knew about that. Thanks for pointing it out. I will do this and let you know. However, the issue was addressed by Porsche Rocklin.

Ragestar7

An oil change is simple, but it set me back by $400. Shell Shocked lol.

lml999

You need to find a good independent mechanic or DIY. You're talking about $100 in oil and a $15 filter.

patpatpat

If the multi function button works I say get some electronic cleaners in an aerosol can with a red straw. Spray it around the buttons and gaps.

this solved my problem because mine was due to a dirty electrical contact underneath

lml999

Good advice.

No more drinking coffee/soda in the car!

wyowolf

Jeez... 1k for a battery and 400 for an oil change!! I should have became a Porsche Mech instead of fixing aircraft...

Ragestar7

I do know of a good Indy, but jeez, he was booked out for like 2-3 months.

Ragestar7

I'm actually surprised, why THEY did not want to replace the auto start stop button first and then do the battery, should they not start off with the CHEAPEST route first? Or they avoided that since the button would be counted as part of CPO and they were hoping to make me pay for the battery?