Rick150

Many electrical problems with my 2009 TS, Bosch wet cell battery seemed to be ok, CCA test was good but it looked like it was 90% of the battery holder size. Did a check with a battery supplier and found that the battery was not for this vehicle, it was 760CCA so I put in the AGM replacement at 970CCA and all my electrical troubles went away.

Look at the head of the bolts.

Bolt Head Grade/Strength Identifiers

HENRYSAUTOWAREHOUSE.COM

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You can usually figure out the grade, or strength, of a bolt by looking at the markings on its head. English bolts are categorized by grade and metric by strength class.

Did you check the drive shaft bearing? When the rubber mount lets go it makes a thunk sound as the power comes on and off and can make a roar noise when the bearing itself is failing.

From VW diag which shares Porsche codes.

P1749 18157 Transmission Control Unit Incorrect Coded

Probably  a glitch as Loren suggested.

If you have done 90k km or multiples of the the cardon shaft bearing need replacing before it costs you a whole shaft. Easy to check, get a small wreaking bar and move the shaft up and down, if you see cracks in the rubber around the bearing then replace it now!

The connection is there.

Thanks for posting the update, so important for the future when we are trying to track down faults 👍

Looking ahead I wanted to buy front brake pads but for some reason I keep getting offered pads for the 355mm disks and not the 380mm disks. I even went through part supplier catalogues showing them that 19" wheels wouldn't even fit over my disks.  No dealer for a thousand miles and they would want crazy prices anyway. Anybody know what compound I should use and where to find them without feeling I am paying extra just for the brand of vehicle?

This should help, valid for all models.

Because the have a galvanised body in high humidity environments or ingress of water it can set up on a dissimilar metal like fuses, earths ect. Common when the car hasn't been used in a while and the air inside is not being changed out. Check your fuses on side of the dash by pulling them, check and put back in, quite often things come to life.  Check earth bonds, there are lots of them. Also this galvanic action can get into the wiring if the insulation is cracked. Good luck!

As I said, check the fuses. The Cayenne has a Galv body and any moisture around causes electrolysis, fuses ect being copper based will form an oxide. Nice idea Porsche but hell on the electrics!

Here is what I have that may be some help.

There is a brown wire under the passengers seat from PDCC control unit terminal 31 to ground, check. RH fuse box on dash, Fuse 44 (5A) & 27 (15A) may need to be reseated, pull out and push them back in after inspection.

I own that model with 90km. Just about to replace the driveshaft bearing. They are very good as long as you keep the maintenance up, oil changes, transmission as well.

They say the better engine which I have has less issues because the the cylinders are Structurally Honed. Not much data on this model, not many around as the cost 2.5 times the base model.

Does the engine look like mine, 9PAAN1 ?

There can be two supplies if you have a battery under the spare wheel but if you have only one battery it splits off to supply the electrics and the starting circuit. Follow the + line under the seat  and you will find fuses and the line to the power relay. Check where the power stops, could be a fuse or a starting relay problem.

Follow the + wire from the battery under the seat till you find the 250 Amp fuses, there are 2 and this is the supply to the right hand fuse box.

Not sure what model, 955 or 957. If you have secondary battery under the spare wheel it may be flat?

These bolts are tightened to 270Nm or 200 ftlb, it's obvious that at some time they have been removed and put back NOT according to the service instructions. I would check the other side, let us know.

What model, 955 or 957?

Again thanks for the update. These vehicles have limited space around sensors and controllers. Seems to me any repair is a planned attack to get to the offending item (s).

All said they are fun and I don't take the numerous fault codes seriously, I just get around to fixing it in my time.

There are 2 wires to the sensors, one is brown. To identify the sensor your talking about do you know the other wire color, green/brown?

My electrical diagram only shows what's already posted, valid for 2009 4.8L, 3.6L & 4.8L Turbo.

Thanks for the update. Imagine the cost of getting a repair shop to do all this!

This may help?

Can you take a close pic of the belt? Bend it back 180 degrees so we can see the drive side. Something strange going on unless it's well past it's replacement time.

Usually belts just fly off but yours seems to have a lot of energy stored, like a rubber band. If it's not just a belt failure due to age then it's probably going to happen again so you need to understand why it failed.

Check the pulleys by rotating them, they should be free running with no noise.

16ftlb for high and low unions.