2006 Cayenne S - Tiptronic won't start - need help figuring out what could be wrong

[Tammy88]

Hi, 

I have a 2006 Porsche Cayenne S - Tiptronic and when I turn the ignition to crank it all the lights come on, the radio and anything that would normally happen happens except it won't crank.  The car will go into neutral or any other gear just fine.  I did notice the break pedal won't press down as far as it normally would.  There are no error codes on the screen at all.  I replaced the battery last year and it's been just fine. I read somewhere that I should disconnect the battery to reset the car to see if that works so I did that and it did not fix the problem.  Do you have any suggestions on what I can check or what could be the problem? I'm feeling it's something simple and would like to know before I give up and take it to the dealer.  Thanks for your help!

[angusc]

Do you have the auxiliary battery in the truck as well as the main battery under the left-hand seat? Maybe worth checking.

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[Tammy88]

I'm not sure if I have an auxillary battery, but I will check.  When I find the auxillary battery, what should I look for? FYI - I replaced the battery under the drivers seat.   

[angusc]

Yeah me too, I replaced my under seat battery and then found there is another battery in the trunk. Was an optional extra. However my car started ok once the under seat battery had been replaced. The one in the trunk is a Varta battery so has been changed at some point in time since the car was new. The old one under the seat was a Porsche battery. I will probably have the trunk battery tested before replacing it but will replace it anyway, as I park my car for months at a time between use.

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[lewisweller]

18 hours ago, Tammy88 said:

Hi, 

I have a 2006 Porsche Cayenne S - Tiptronic and when I turn the ignition to crank it all the lights come on, the radio and anything that would normally happen happens except it won't crank.  The car will go into neutral or any other gear just fine.  I did notice the break pedal won't press down as far as it normally would.  There are no error codes on the screen at all.  I replaced the battery last year and it's been just fine. I read somewhere that I should disconnect the battery to reset the car to see if that works so I did that and it did not fix the problem.  Do you have any suggestions on what I can check or what could be the problem? I'm feeling it's something simple and would like to know before I give up and take it to the dealer.  Thanks for your help!

From my understanding if the main battery is good it will start, second battery or not ,(maybe wrong here but I'm sure the fail safe logic is that). If you can select gears and lights etc are on then I rule out brake pedal sensor and ignition position/entry drive kessy system as they won't allow dash lights to come on if an issue. Also the gear couldn't be selected from park if it was not working. 

Can you hear the starter click? If yes then two possibles, first the starter motor is faulty or the current/voltage to start is not enough, second possibility is an Auxiliary is jammed ie the alternator (ask me how I know) the water pump the AC compressor to the engine is seized. 

If you have a click then release the serpentine belt tensioner and take the belt off the water pump pulley. You can then proceed to spin the pulleys of water pump alternator and AC which should all turn by hand, also the guide roller too. The crankshaft pulley you would need a spanner or socket and ratchet to rotate the engine by hand. Very unlike you engine is seized so I wouldn't bother to go any further. Next if all free to turn is remove the inlet manifold and remove the start motor.  It actually really simple to do. I rebuilt mine after a good clean following an investigation into a non start which was a seized alternator. The starter motor condition was very good brush length was plenty and no visible wear at 115k km. What's your mileage? 

 

If no starter motor click then try jump leads from another big engined car/4x4 or strong heavy duty battery on the battery connector points in the engine bay right side under cover trim, this will rule out power delivery issue. 

 

If this doesnt work then starter relay, fuses or ignition switch crank position problem or start wire to starter motor fault. 

 

Any fault codes?  

Edited November 6, 2016 by lewisweller

[Tammy88]

Hi, 

My local mechanic looked at it and told me it was the starter, but I don't always trust that he has thoroughly investigated enough to determine the problem  He tends to go with the largest component and then will do a process of elimination. When I turn the key I do hear the starter click. I looked at the battery voltage and it doesn't go all the way to 12.  It is on the notch below 12. Since the voltage appears to be too low, what should I check?

 

[JFP in PA]

You could have the battery load tested, but if it is below 12V, it is probably toast.

[lewisweller]

4 hours ago, Tammy88 said:

Hi, 

My local mechanic looked at it and told me it was the starter, but I don't always trust that he has thoroughly investigated enough to determine the problem  He tends to go with the largest component and then will do a process of elimination. When I turn the key I do hear the starter click. I looked at the battery voltage and it doesn't go all the way to 12.  It is on the notch below 12. Since the voltage appears to be too low, what should I check?

 

If you don't have 12.6 volts when measuring with multi meter from the battery jumping terminals in the engine bay then the battery is done or charging problem exists.  

Another test, put the front lights on and have someone crank it, if the light do very dim or cut off the hello battery. 

Get another car and jump start it, if it starts then test the battery and see if the charging voltage is above 13.2v and ideally around 13.8v. Go for a long drive with as much electrical load off as possible and come back to your preferred place to stop (it may not start again), then switch off and get multi meter and test voltage whilst someone else cranks to start the engine again, if you see the voltage start at less then 12.6 volts then drop to less than 9.8volts when cranking over (assuming it turns over now) then the battery is most likely fudged. Even after just one year short journeys parasitic power leaks drain the battery when parked up and or the alternator failing cause these cars batteries to not last long. 

Also make sure you get the right battery 110ah and 950cca. 

 

I replaced my battery when I bought the car in Feb, the alternator failed 6 months later and I cheekly Sent the battery back to claim warranty as it had not been charging properly and was not passing my drop test when cranking, it would go to 8.8 volts, a new battery will hold almost 10volts which is perfect. They confirmed it was faulty and replaced foc under the warranty.