Multiple fault codes in 2005 Cayenne Turbo

[Ahsai]

I don't have the cayenne wiring diagrams but a typical cam sensor is the hall-effect type, which has 3 pins: +5v power, signal (square wave), and ground. I think at least you can check if the bank 1 cam sensor has power with key on engine off. Best is to get the wiring diagram so you can check the connection between the sensor and the DME too.

[SpawnyWhippet]

I ran some tests with my Durametric today. It looks like there are definitely problems with the camshaft or camshaft sensor. Camshaft deviation is not even reading on bank A.

The cylinder faults and misfires show something is clearly wrong with cylinder 3.

I am not skilled enough to further interpret these graphs, or know how to troubleshoot any further. Neither is my local Porsche dealer, who just wants to throw every Cayenne part at it until the problem stops.

 

Cylinder fault counter

 

Camshaft specified angle

 

Camshaft deviation

 

Camshaft actual angle

 

Misfire counter

Edited March 31, 2016 by SpawnyWhippet

[Porschetech3]

If I were you , I would spend a little time searching through TSB's . I seem to remember about 10 years ago a TSB about the ground wire connections on top of the engine. There is a ground for each bank, if the ground is faulty it will cause all sorts of crazy codes and intermittent problems. Its been quite a few years since I have fixed one of those , but I have seen a dozen of so.

[SpawnyWhippet]

Took the CTT to a independent specialist today. He hooked it up to his scanner / scope and not good news. He told me the cams were way out of deviation. Bank 2 was 15 deg out, Bank 1 was not even giving a measurement. Both cam sensors were giving readings. His opinion is that the rough running and misfires are most likely due to stretched timing chains.

 

He said the only real corrective action was to replace the timing chains and plastic parts, which meant dropping and stripping the engine - 30 plus hours and a few thousand in parts. Not much change from $10k.

 

Is there any way that the cam timing can be brought back into spec (+- 6 deg) without doing all that? No kind of mechanical adjustment that can be done on the cams without pulling or stripping the engine?

 

 

 

[Ahsai]

Indeed looks like a big job. Hope others who have done it will chime in.

http://www.6speedonline.com/forums/cayenne-955-957/268277-04-ctt-timing-chain-replacement-semi-diy.html

[Gonzales]

Hi All, had rough idle with cel and nr of faults. I did camera inspection and nothing. I did compression test and one cylinder show 0. Finally hole in exhaust valve. Changed valve spring and cam chain, sparks, coils. Now is much better but still misfire on left bank. No misfire fault. Strange. Will look for proper grounding. In The mean time my t-pipe blows. Waiting for Alu to be produced. Ctt 2005.

[lewisweller1982]

Spawny I feel your pain.

I got a ctt just done Head gasket done and full rebuild and still runs rough at part throttle load, no CEL no DTC, garage gave me it back and I just drive for a few km before giving it back to them to fix properly. Nightmare costing me a fortune.

sorry I cant be of much help, the 4k limiter set is defo the DME limiting rpm because sensor parameters are not in spec, stretched chains seems to be correct if both bank have issues and the sensor wave form and signal is plausible. 

Post what you find fixes this as its good for other despite the pain for you  :(

[SpawnyWhippet]

I gave up on the car and sold it for pennies on the dollar on Craigslist. Too many consecutive very large repairs in a very short time. Surprising for such an expensive car with so few miles (80k), when everything else looked and smelt like brand new. This is the second Cayenne Turbo I had to almost give away.

[Gonzales]

Idle problem solved. 5000km Spark plug with 0 (zero) gap. But now tranny failed. 721 code. Only reverse and 5th gear forward.

[Loren]

Idle problem solved. 5000km Spark plug with 0 (zero) gap. But now tranny failed. 721 code. Only reverse and 5th gear forward.

 

Fault code P0721

Output shaft speed inductive pickup [Output Speed Sensor Circuit Range/Performance]

 

Possible causes of fault

- 'Implausible signal', mechanical damage in sensor wheel or inductive pickup

- 'Implausible signal', inductive pickup faulty

- 'Implausible signal', Tiptronic control module faulty

 

Check each wheel sensor. You should get 24 pulses per tire revolution.

Remove ATF pan on the transmission (first drain fluid). Remove ATF filter, check plug/wiring and inductive pickup for damage.

[Gonzales]

Finally managed to pull out trans - DIY. Nightmare but I did it. Trans is damaged for sure. Will post as soon as I have time to open it.


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