2004 cayenne S

Short version: dead battery, battery tested good recharged, reinstalled, place key in ignition dashboard unresponsive .

​​​​​​​when I place the key into the ignition I do here something click in the dash but again no lights in the dash at all no mileage being displayed. Please help where do I even begin?


Long story:
Was sitting in the parking lot waiting for my food to finish listening to music. I forgot I had turned the key without stepping on the brake pedal there for sitting there with the ignition on.

i got a jump then moved on with my life so I thought . Car wouldn't start again in the morning due to battery being low. Took battery out to AutoZone got tested battery was still good and they recharged it for me.

hook battery backup now when I put my key in the dash nothing happens. The mileage doesn't even light up nor does the central Locking System seem to be working. The key still works and will release the rear hatch. Hazard lights flash indicating doors supposed to be locking and unlocking but they do not.

when I place the key into the ignition I do here something click in the dash but again no lights in the dash at all no mileage being displayed. Please help where do I even begin?

 

Buy a new battery and install it. I'm guessing the Autozone test didn't really put enough load on the battery to find the failure. Often this sort of failure (where the battery reads OK without a heavy load, and where it appears to take a charge) is due to a cracked internal lead connector in the battery. Under low load conditions it conducts electricity - under high load conditions it doesn't.

All the signs you give point to a bad battery.. so..

 

agree that you probably need to replace the battery, however I also think you should check for corrosion of the wiring under the driver's carpet (under the dead pedal) there are several splices in the wiring that get damp and corrode. I replaced my battery due to some weird issues and a slow starter. Then 4 days later I got a tone of faults and a disabled car. I cleaned up the wiring under the driver's feet and it has been fine since.

I had to use a Durametric to reset the car to get it running again, btw. TO do this you have to have a really good battery, hold your foot on the brake for 30s (to wake up the CANbus) while trying to connect to the cars computer with either an official Porsche scan tool (PIWIS), a Durametric, or a iCarscan tool.

read this thread
https://rennlist.com/forums/porsche-...l#post13710465

 

Before buying a new battery, I would invest in a multimeter and battery charger. Those should last a lot longer than any battery will.

When you had it tested at Autozone, were they testing it as if they'd need to do a warranty replacement if it were bad? If so, that would make their test results even more doubtful.

BTW, voltmeter on the jump ports in the engine bay would very quickly get you good info in this debugging. Far simpler than battery removal, autozone trip, etc.

 

UPDATE:

Finally bit the bullet and bought another battery when I took the old battery back to autozone to get tested again, this time it failed. Dash lit back up when I inserted the key as normal now after reinstall. Beginning to think the battery may have been ready to fail for a while now because all my lights seem brighter. Of course I wont know for sure until I go to start the car tomorrow morning.