spooltime

I hate being the bearer of bad news, but to remove the driver side trim panel covering the 4-zone rear zone AC unit, you essentially have to remove the entire rear compartment lining as well as the rear seats.  I had to replace my PDC control unit after it failed, and it is located at the bottom left of the rear AC unit.  Replacing it was easy; it was removing all of the trim and the seats that was the PITA.  Here's a link with some pictures when I did the repair.  Looks like I didn't write down all of the steps to get the trim out. http://rennlist.com/forums/porsche-cayenne-forum/785774-park-assist-control-module-replacement.html

My expansion tank is now on day-by-day status, with coolant periodically dripping to the floor, and the engine temperatures fluctuating erratically. Also had an earlier low coolant warning that caught me off guard, but I topped it up until I could get the parts in.  I've got the necessary parts to replace on order, and had a question regarding the factory shop manual procedure for replacing versus other methods I've seen described on the internet.

Specifically, my question relates to draining the expansion tank before removing.  The shop manual calls for the entire cooling system to be drained at the radiator, while other write-ups I've found suggest it's sufficient to siphon out the expansion tank to remove without draining out the coolant.  Obviously, the latter approach is less involved, but my question is if it's really necessary to go for the full drainage method described in the shop manual?

Just do not overfill.

 

Best to be patient and let the front and rear diffs, and the transfer case fully drain and then drip.  If you're not in a rush, let them drip for a minimum of 30 minutes and you'll know virtually all of the old fluid is out.  When the diffs and transfer case are topped up with new fluid to the bottom edge of the fill hole (i.e., it starts to drain out of the upper hole), you're good to go. Just be sure the vehicle is level while doing this.  No point in trying to measure precise fluid amounts.

FWIW, I personally installed the Dension Gateway 500S BT and have been very satisfied with it.  Using an iPod to instead of the factory CD changer is easily accomplished with the Dension unit, and the BT has worked flawlessly as well.  I don't have any experience with other brands.

It's unfortunate you had a negative experience, but perhaps next time some additional due diligence before purchase might have helped avert some of the issues.  My turbo is 9 years old, but it's been quite reliable for the two years I've enjoyed it thus far.

Thanks for the replies.  I'll defer doing this job for the time being.

When the vehicle codes, indicating that the sensor is failing,

 

So no reason to do preventative maintenance before one of the sensor codes?  I've always understood that as the "pre" sensor wears out, the mixture starts richening up and fuel efficiency declines..  Just trying to stay ahead of the curve.

I did a search and couldn't find anything of much use.

What's the consensus on when O2 sensors on the turbo engine should be replaced?  Is there a specific mileage requirement, or is it sufficient to rely on the ME 7.1.1's built-in O2 sensor monitoring function and just wait until the "check engine" light illuminates with a corresponding O2 fault code?  The O2 sensors do not appear on either the "minor" or "major" service checklists.  I note that replacement Bosch sensors are supposed to have a service life of approximately 167,500 miles before requiring replacement, but I've always had it in my mind that to maintain optimal performance and fuel efficiency, these ought to be done at about 100,000.  Anyway, my Cayenne has tipped to the north side of 100,000 miles, so hence the questions.  TIA.

This one shows the lock circuit.  Looks like power is supplied to the lock module by the KESSY unit (which you already know).  The unit itself apparently is located under the dash in the location shown and appears to be just to the left of the steering column (as you're looking forward).  Probably a b*itch to get to.

WIRING 34.pdf

ELECTRICAL COMPONENT LOCATION 14.pdf

Hope this helps.

steering column.pdf

I replaced the battery with the big Interstate H9 battery and cleared all faults using Durametric.  The electrical system fault returned, showing only part number "11" (with no fault code), so I contacted Durametric support and they sent me a new electrical system diagnostic file to try.  When I used the new software file, it returned with the 0907 fault, but still only showed part number 11 as being the source of the fault.  I contacted them again and they said they're still working on getting the identification aspect of the electrical system diagnostic to report proper values.  But as least with the fault code and the diagnostic steps I received, I have some more possibilities to investigate.  Any other suggestions?

Thanks very much,  Time to dig out the multimeter.

I've been getting a P0907 fault code reported for the electrical system, which is a load management issue that supposedly is triggered when there's a voltgage drop.   I replaced the battery, and my voltgage gauge shows a nice, steady 13.9 - 14.1 volts while the engine is running, so it seems like the alternator is okay.  What other diagnositc steps can I take before I surrender and have my dealer's service department look into it?

In poking around various tuning forums, one suggestion is that a more accurate reading can be obtained by tapping the "Y" intake plenum in front of the throttle body.  I wonder if that makes more sense than installing a T adapter into a vacuum line coming off the rear of the intake?  The pressure and air temperature sensor for the DME is located on the top side of the "Y" plenum, if that matters.  Thoughts?

Can anyone share some information on the best location in 955 Cayenne Turbo's vacumn lines to splice in a T-fitting as a source for an aftermarket boost gauge?  The factory gauge seems like it doesn't give a full reading and is reading off a sensor, not actual boost, anyway.  I'd like to install a more accurate boost gauge.

I cleared the fault code and didn't think about saving a screen shot at the time.  If it recurs, I'll save it and send it to Durametric to see if they can shed some light on it.

I'm using the latest version, 6.5.0.6.  Vehicle is a '06 Turbo S.  Is there a way to determine what module 11 is?  Thanks!

I did my periodic Durametric read out of any stored fault codes, and was fully expecting to find one for the DME since my check engine light had briefly illuminated and then went out maybe a month ago.  Instead, no DME faults, but one for the electrical system.

The Durametric reported a code for module "11", but I couldn't obtain any further information about what module that is.  Is there a way to get the Durametric software to reveal more data?  More importantly, does anyone know what a fault in module 11 is?

I cleared the fault code and will see if it returns, but in the meantime, it would be nice to know what the reported fault is.

Autobahn cruising at 100-140 mph ups my consumption too.

Wish I could have this problem, but the law enforcement types would not be pleased with those kinds of speeds. :cheers:  

Just curious about oil consumption.  My Cayenne is a daily driver commuter vehicle with lots of stop and go driving.  I probably add a quart in total every 800 - 1,000 miles.  So in planning for a trip, I packed 2 quarts and figured that would cover me for the 1,700 mile round trip.

I checked the oil at my destination and it was barely down at all, so I didn't add anything.  After returning home last night after the second segment of the trip, I checked it again this morning and it was down only just a tad on the dipstick.  Maybe only 4 or 5 OUNCES (not quarts) of consumption over a 1,700 mile trip averaging about 70 - 75 MPH.

Obviously, I was happy and am feeling really good about the condition of my 95K engine, but I simply couldn't believe the difference in consumption between in-city driving and steady state interstate driving.  What would account for the difference in oil consumption? Anyone have some thoughts?

 

 

This is from a very credible source:

"...This N-rating isn’t free.  It comes at a price.  All of that development and testing costs the tire manufacturers and Porsche a penny or two.  For instance, one of the most popular tires for a newer Porsche is the new Michelin Pilot Super Sport (Max Performance Summer) 265/35/ZR19 N0.  It can be purchased from TireRack.com for $419.00 each.

The same tire, without the N0-rating but with the exact same specs is offered by TireRack.com for $297.00 each...."

 

http://www.pedrosgarage.com/Site_5/For_the_Nth_time.html

 

Obviously Pedro didn't read what he wrote on his website and you didn't post the relevant portion of his note about "N" tires:

 

"An N-rated tire is a tire from one of various Porsche-approved tire manufacturers that has passed a series of difficult and diverse tests designed by Porsche engineers to ensure maximum performance and safety under a wide range of driving conditions. To have this rating stamped on the side of their tires, and to be an OEM (Original Equipment Manufacturer) tire provider for Porsche requires the joint product development efforts of the particular manufacturer’s tire engineers working alongside the Porsche vehicle engineers." 

 

If Pedro's quote above is true, then it goes without saying that a non-N spec tire from the same manufacturer doesn't have the "exact same specs" unless we can assume that the tire manufacturer allows its jointly developed tire with Porsche to also be its mass market tire, just without using the "N" tire mold.  Pedro probably doesn't know any more about this than wrinkledpants or me and is just going on heresay like the rest of us.

 

I think we can all agree that a Cayenne will be fine without an N spec tire if you're not so inclined, but the GT3 analogy is bogus.  The discussion is about using a tire that Porsche spec'd for the specific vehicle (Cayenne) versus using one that wasn't.  What should or shouldn't go on a GT3 is irrelevant.

 

 

None of the tires that carry the N1 or N0 rating were made any differently for Porsche.

 

And you know this because of your current or former employment with Porsche or a tire manufacturer supplying N rated tires?   Just curious.

Based on my experience in the automotive and aerospace industries....it's 100% marketting....

It may be for marketing purposes, but that doesn't change the fact that N-spec tires have met specified Porsche engineering criteria for the specific application and fitment their approved for.  Let's call that a base line of acceptable performance.  Other non-N tires may be able to meet the criteria as well, but simply put, have not,  for whatever reason.  I prefer trusting tires that have; I consider them to be a safety feature of the vehicle.

 

 

So i can 100% tell you that non of the discount tires are on this list.....reason being they simply don't want to spend the money to qualify them with Porsche.

 

Or more likely, they can't.

 

While i do believe Auto MFG Engineers do the analysis to validate the designs of the 3rd party supplier, you have to remember that this "validation" is mostly marketing and cost driven.  This is why you will see only big name companies qualify with auto manufacturing.

 

It's very expensive to make a unique tire mold with the special "N" designation on the sidewall.  It's not new for major tire companies to collaborate with high performance vehicle manufacturers to design tires intended to enhance the performance and handling of the vehicle (e.g., Goodyear - Corvette; Pirelli - Ferrari;  Yokohama - NSX; etc., etc.)  I think there's much more to it than mere marketing.

 

This is also why you will see items that were once qualified, drop off the list.....they either failed, or did not think it was worth recertifying.  So take the Porsche "seal of approval" with a grain of salt.

 

Tire designs and compounds are constantly being tweaked and improved.  A single manufacturer may go from "N0" to "N1" to "N2" on the same type of tire as changes are made.  Others are determined to be unacceptable in use (after initially obtaining a designation) and are dropped.

 

Like I said, there's nothing wrong with using non N-spec tires; they just haven't been subjected to the same level of testing and quality control the N-rated tires have had.

 

If you really want to eliminate the mystery regarding proper tire selection for your vehicle, it's simple.  Go to the Porsche website and download the latest approved tires sheet, and then pick one in the correct size for your vehicle that's shown in bold lettering on the list.  The ones in bold are the most current approved version of the tire (e.g., N1 versus N0).  If you want even further refinement, go to one of the non-USA Porsche websites and download the approved tires sheet that has the EU tire rating specs shown - for rolling resistance, wet handling, and noise levels.  Then pick a tire that rates the highest with the feature that's most important to you.  Do this and you'll have Porsche-spec'ed tires that were manufactured specifically in collaboration between Porsche engineers and the tire manufacturer engineers with your vehicle in mind.  N-spec tires may be a bit more expensive, but in many regards, tires are the single most important safety feature on your car. 

This isn't saying, of course, that you can't or shouldn't use Porsche N-rated tires on your vehicle; that's your decision based on your budget and whatever other factors you base your decision on.  But in my experience thus far, the N-rated tires have given much better actual driving results than the non-N-rated tires I've tried. YMMV.