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Loren => what do you think

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Attached is an image of the original problem / resolution I had on my 2006 Cayenne S. I got it back on the 19th of this month (last Thursday). Yesterday (7/25) the same problem happened (started but threw multiple errors on start up. I stopped the engine and it would not restart).

When I called the dealership, they agreed to have it towed. Although it hasn’t been diagnosed yet again, they did say that there must be more problems than the Tyco fuse and Airbag Control unit.

My questions:

When my car first threw errors last week, but before the tow truck came, the car would sometimes start with no error codes whatsoever. If a Tyco fuse (pyrotechnically designed to trip in a accident) blows, why would I have been able to periodically run the car with no errors?

Does it make sense that I would have the exact same problem, even after a $1,000 USD part was replaced?

I do not have the original error codes.

I am just really worried it is going to be a $5,000 fix on top of my $2,200 original 'fix' ... and in the end, I will not feel comfortable that the car is reliable enough to drive to a customer's site, the grocery store or even take it on vacation.

Any thoughts?


Edited by tom__w
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Dealership called and said that the car starts and runs no problem. As well, there are NO error codes stored. He wanted to know what stuff I have added to the car:

Hard wired Radar Whistler Detector

Dension (or similar...actually Viseeo) Bluetooth receiver

LED Lighting

Do you see any of these things causing this kind of problem? If not, I'm going to be ankle deep into diagnostic costs.

PS - And guess what, the dealer couldn't explain why the car would run fine after the first reported error but before they replaced the 'damaged' parts. Did I already say help?

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I don't think the parts you added would impact any control unit related to happy running of the engine since they are clearly separate UNLESS you hooked into existing power circuits that you don't know maybe leads to a CU.

I have seen where a denison type unit will cause problems with PIWIS reading the system which is why they have the bypass switch.

But if fuses were blown obviously something is wrong. To overload it sufficient to blow the fuse I would be looking at foreign loads connected same as the dealer is now questioning. perhaps one of those is failing and drawing to much. Next step would be to isolate them from the system

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I suppose I am just wondering how my car could have started and ran fine (** below) before the fuse was replaced?


Clunk while driving, errors. Stopped car would not restart (multiple errors)

** Started car 2 hours later and got home without issues or errors

Tried to start again and errors..no start. Towed to dealership

** Started at dealership and drove off flatbed. Didn't immediately start for repair tech.

Dealer replaced parts (fuse / controller)

Drove home and good for 4 days

Dead again - towed to delaer

Starts and runs fine at dealer

No error codes


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What fuses failed?

I would inspect wiring harnesses for damage from being worn or rodent damage in the engine compartment. It would help to know what circuits are in suspect at had the failed fuses. When it doesn't start is it not cranking over or cranks fine but doesn't flash up?

If it's blowing fuse 7 and 8 in the main fuse block near the brake master cylinder then those are for the fuel injectors/ignition coils, you could have a failing coil on both banks that could be at fault but this wouldn't cause a intermittent no start condition.

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Well the dealer called me and said that they were finally able to get it to not start. Now they can start 'really' diagnosing the problem.

sigh.... :huh:

And yes Loren, I specifically asked them to check the battery / ground

And no, the car doesn't even turn over. The display says press pedal, but of course that doesn't help in my case.

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Well the dealer called today and said that they have checked the battery and grounds. That was one of the first things they checked. They are going to hold onto it and have one of their guys drive it to and from work for a few days. I figured why not, I'm not taking it back until I can feel confident that the problem has been rectified.

Any more thoughts / ideas?

So sad ... I hate the thought of having to get rid of it because I don't feel confident it won't break down. :(

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Dont know if i can help you but your story sounds like the same strange problem o had some month ago. After changing coils and plugs for new ones the car behaved like yours. Sometimes running fine, sometimes not. I called

Porsche. No idea. What i did: changed all plugs again and bought new battery which is under the seat. Since that time no problem at all.

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  • 2 weeks later...

Well I got the car back from the dealer. Considering the previous repair, they picked up the towing cost as well as splitting the labor. Total came out to $400.

Although they can't say with 100% certainty that it is fixed, their service manager drove it back and forth from home for almost 2 weeks putting 500 miles on my car. It didn't fail once while he had it.

They say that the drain cowl was clogged and that there was a control box / wires that appeared to get wet. Some of the wires were slightly corroded. They cleared the drain and re-taped alll the connections after checking them.

It seems to be OK. But only time will tell.

All in, this problem has cost me $2,700 :censored:

Time to cut my losses and sell???

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