Kabb

Hi all - new joiner to the forum.

my cayenne S (2019, 25,000 town running miles) has been a faultless dream car for 2 years but in recent weeks has started playing up with the start/stop failing, engine light now on (not flashing!). The ACC and lane change assist also fails now and again.

The engine fan goes crazy when I switch the car off.

Any one have this problem? Is it time for a dealer visit?

appreciate any views and ideas.

Thanks in advance!

Needsdecaf

Strange combo of issues. Original battery? Can cause strange behavior when older.

Ticket Target

When there is an engine issue the first thing the system does to protect itself is defeat the stop/start. You're going to need to visit a shop to have it diagnosed.

Kabb

Thanks both - the battery is the factory fitted one.

will book the car in and post the diagnosis.

cheers

f82shabiyaoqiu

Same thing happened to mine today, please let me know if you got a answer

Kabb

Will do - mine is booked in for 5th May so will be a few weeks before I get an answer.

PorscheACC

When mote than one subsystem start to have problems out of the sudden, you will need to check the battery and its voltage..

Electronic subsystems tend to randomnly fail to start correctly when the voltage is low, further aggravated by each subsystem dropping the voltage further while trying to boot.

In addition, depending many subsystems require/depend other subsystems to start correctly and they will fail to start.

Vehicles never have more than one subsystem fail at the same time. If your mechanic tries to charge you to fix each system included in of OBDII problem error list/lights, go to an honest mechanic to get a second opinion.

joisey_guy

Mine is at the dealership getting fixed for same issue. The service rep said it was a thermostat sensor that went bad.

Kabb

Tried starting the car and fan went crazy. Called out roadside assistance who plugged the car in to carry out a diagnostic. Seems like a thermostat had glitched so he cleared the error and I took the car for a spirited 30 min drive to see if it comes up again.

all working fine now. Start / stop reactivated. Fan working normally and engine light gone.

I’ve booked the car in so it’ll have a Porsche health check anyway but looks like, for now, the issue was just a sensor glitch but now it’s been reset, it is behaving!

Kabb

Did the dealer manage to fix it? Was it a thermostat sensor issue? Would be interested in how much the repair cost. Cheers

joisey_guy

Mine is still at the dealership. They had to replace the vacuum hose too which they had to order. It will likely arrive today so hopefully I will get my car back tomorrow. Mine is still under warranty so will not be able to provide cost.

Galaxy1359

I have the same experience with my Porsche Cayenne 2019,stop start failed,the fan works non stop and the engine light come up in dashboard .any idea what is the issue?

OldSharkey

Exact same here. Began yesterday. 2019 Cayenne base. Battery at 13.15v with negative disconnected. Have a service appointment Wednesday.

Galaxy1359

Very strange .low mileage car with full service history getting this

Galaxy1359

@OldSharkey Did you take your car to the dealer for fix?what was the outcome?how much did it cost?