pbwillz

2008 987.1 Boxster, 76k miles.

CEL came on and pulled the codes listed below mostly relating to valve lift and cylinder misfire. I noticed car idles rough and vibrates more than it should. I don’t have any knowledge if coil packs / spark plugs were replaced from prior owner but maybe that is a good starting point?

Initially, I thought these were earlier signs of a bad AOS. Occasionally, I see smoke on startup (which tapers off) when the car isn’t driven for a week and oil burning noticeable at the exhaust. On a more recent humid day, the cloud of smoke was thicker and could be seen from inside the cabin but seems to have been an one-off experience. I did the oil cap test and I was able to pull off the cap with vacuum holding it. Will do a manometer next to determine condition.

Appreciate the help !

P1371 Valve Lift Control Checksum Error
P1359 Valve Lift Control, Cylinder 1
P1361 Valve Lift Control, Cylinder 2
P1363 Valve Lift Control, Cylinder 3
P0300 Random Multiple Cylinder misfire detected
P0301 Misfire, cylinder 1
P0302 Misfire, cylinder 2
P0303 Misfire, cylinder 3
C152 Communication PSM control unit (drive)

harveyf

You should concentrate on the Valve Lift Control codes. Very high level, your engine has Variocam Plus. This is a combination of active valve timing and active valve lift on the intake cam. Search on Variable Valve Lift on youtube and you will find mutliple tutorials. Unless you are very hands on and have some diagnostic equipment, you should probably take it to a shop for diagnosis. The fail safe position is low intake valve lift so I think it is safe to drive the car but I would get someone who knows what they doing to look at it sooner rather than later.

If you are hands on, you can use a Durametric to manually activate the valve lift, as a test. Many would consider swapping the actuators between the two banks to see if the problem follows the actuator.

Regarding Checksum Error, Porsche software does a variety of checks behind the scene, looking for "implausible" sensor and actuator data, typically voltages or resistances. If they go out of range, it will kick out a Checksum Error. Think shorts to ground, open circuits, or values that are "outside the box" of a normal operating range.

pbwillz

Thanks for the input. Took it to my Indy and it turned out to be bad spark plugs, ignition coils, and variable cam adjuster solenoid. Repairs completed and car is running again.