Error codes, engine running rough, check engine blinking....

[rslay]

I have a 2009 Cayenne S with about 131K miles.  Just spent $2700 replacing the fuel pump and thermostat so I'm not a happy camper.  Today the engine started running rough and the check engine light is blinking.  I hooked up the Durametric and got 3 error codes:

 

1352 Valve lift control cylinder 6

2A04 Mixture beh. cat. conv Bank 2

0306 DME control unit faulty: EEPROM no signal/comm

 

I found some info on the P0306 code:

Possible causes of OBD code P0306
A code P0306 may mean that one or more of the following has happened: Faulty spark plug or wire Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector Burned exhaust valve Faulty catalytic converter(s) Running out of fuel Poor compression Defective computer  ​

 

Where is the O2 sensor?  I'd like to start with that.

 

 

thanks,

Richard

Edited September 9, 2015 by rslay

[Loren]

:welcome:

 

The O2 sensor would be the last thing you would change.

If it was the O2 sensor then all of the cylinders on that bank would also have faults.

 

Cayenne's have a history of troublesome ignition coils. Porsche has updated them several times. Do the tests for cracks and resistance and if more than one is suspect replace them all with the latest version.

[Fmscell]

Efficiency or mixture codes are usually the cause of something other than Oxygen Sensors (degraded Cat, engine misfire etc). I would agree that the O2 sensor is not at fault..

[rslay]

The error code is showing cylinder 6.  How do I determine which is # 6? 

[Loren]

The error code is showing cylinder 6.  How do I determine which is # 6? 

 

http://www.renntech.org/forums/tutorials/article/289-cayenne-v8-engine-parts-locations/

[wvicary]

I'd start by checking every electrical connection near where the work was completed and make sure it's all seated correctly.

[CharlieRST]

P0306 is misfire on Cylinder 6, Bank 2 ( engine's left side, second cylinder back from front of engine.)

If the coil connector is loose, you can get misfire. The mis-fire causes the O2 sensor to get 'bad exhaust' out of the cylinder and causes the fault code for mixture before primary catalytic converter 'bank 2'.

If the connector on the coil is secure, and if the coil is okay, ( and if the spark plug is okay... probably) then the mis-fire could be caused by a vacuum leak on cylinder 6. I believe the air plenum is removed to change the thermostat. It's been known to happen that the gasket between the air plenum and the head can fall out of place as the air plenum is lowered in place... or the gasket can catch on the clips of the fuel injectors as the air plenum is lowered in place.. and tear the gasket. Either of these would allow an air leak/vacuum leak.

The description written in the lead of the thread for 0306 doesn't fit P0306.

The fault code involving valve lift for cylinder 6 doesn't fit the pattern of the other 2. Could the description associated with 1352 be incorrect too?

Check for ignition problem or vacuum leak.. fix it and then clear the codes and try it to see if anything returns.

[rslay]

Gosh I hope it's not the gasket.  The dealer will never admit to messing that up.

[rslay]

Turns out the coil was bad.  I replaced it and she's running like a top.  Cleared the error codes and they haven't come back in 45 miles or so.

 

Thanks for the replies and advise!