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I just ordered the sensor from Porsche anyway. Enough is enough. It will be in tomorrow morning. If the new sensor works, I'll let you know. Thanks for the input, Rod
Sorry to break in from 2018, but Google landed me here when I put in "P0155, P0050, then P2254 and P2247". My question for bwestfall or anyone else who knows: When I examined the Bank 2 upstream O2 sensor on my '04 Cayenne S (164,000 km) I tried a 22 mm wrench on it to see if I could budge it. It turned very easily. It had tightness comparable to that of the oil filter cannister, about 17 ft pounds. I realize it's supposed to be at about 35 ft. pounds. I further noticed a number of twists on the cable next to the sensor. The codes led me to look for an air leak, among other possible causes in common. Would a lightly-tightened sensor be the potential cause of my troubles (etest in two months) or is this a faint, final hope before buying the expensive O2 sensor?
After a series of coil failures on my '04 CS I bought a set of eight OEM coils from the local dealer. The car immediately became much more drivable, though the fuel consumption was unchanged. Amazon.ca is an amazing shopper's resource, but not for Porsche ignition coils. Now I'm getting P0155, indicating a problem with the heater on the pre-cat oxygen sensor on the left side. Has anyone found a source of reliable O2 sensors at a good price? Will one do, or will all four need replacement?
My '04 Cayenne S has popped PO155 twice now after ten minutes of driving on the return leg of a 33 mile drive in each case. In between it popped some code related to the computer. I don't recall the number as it looked like a random failure. I suspected the rear battery but it load-tests fine, though it is original. I currently have the connection apart on one O2 sensor on the left side so that I can test the heater circuit with my multimeter, but I'm confused. It seems as though the computer may have shut current off to the wire upon detecting my intrusion, or maybe it's my meter. Does anyone have a reference to troubleshooting the heated circuit on a before-the-cat O2 sensor? Thanks, Rod Croskery
If an '06 has the same grease they put in the servos in my '04, there's a good chance that it has hardened and shut down the gears. Mine were not functioning two and a half years ago when I bought the car. If you can get the right one out, take it apart and see if it's jammed. It might just need some lithium grease. There's a bit more room to work on the right.
Again, pull the glove box and look at the sensor right behind it. Play with the settings. It has a lot of travel on a cable and you will be able to tell immediately if it is sticking or broken. That's the easy one. Three screws remove the glove box, basically. Find online video showing how to change the cabin filter for disassembly instructions.
What are the symptoms of the problem, i.e: what clicks or groans occur, and from where? Does the air conditioner work on MAX? Which vents do what with the system on auto at 70F? Have you made an effort to hear on which side the malfunctioning servo(s) is (are)? Removing the glove box is simple. There is an air control servo right behind it and you can watch it moving as you play with the controls. It is the first one to eliminate. There are one or two more on a plate on the right side, as well. See if you can see them (it) operating as you manipulate the controls. That's a start.
The problem is not that the aftermarket coils on my Cayenne S occasionally fail, it's that they don't fail enough to trip the check engine light so that I can identify which one is the culprit. A couple of months ago #2 blessedly quit in city traffic only an hour from home, so I isolated the culprit (under the engine mount) and had it changed shortly after we arrived home. It had fixed itself once on the highway and run normally on the retreat to my shop. The spark plug had worked its way loose, even though I had torqued them all to specifications at the time of installation along with the new coils two months earlier. Up until the point of the code 302 popping, I had gotten into the habit of downshifting in anticipation of a miss whenever I had to slow down in traffic. But there's still another coil missing a little bit, occasionally. Short of replacing them all with OEM products, does anyone have a way of testing the coils before they get so bad that a code pops up? Has anyone else noticed a loose spark plug after a bout of missing?
You are brave young people and worthy Renntech contributors.
Heidi993 Anything further to report on your project?
We have opened one, to see whats going on inside. Does anyone (Rod?) know which of the pins to attach 12V to move the arms without opening them? There are five pins, a pair by themselves and another three. The two, which I'll call 1 and 2, control the motor. With a 12v charge from a small battery (I used a stair-lift battery), touch the leads to 1 and 2. Observe. Reverse the poles. Observe. The arm should cycle back and forth. If it does not, open it and see why it isn't working. In the case of mine, all but one had old, hardened grease blocking the gears. The other one had a broken arm. When the old grease went out and light petroleum grease went in, the servos went back to work. If anything smells burned inside the servo when you open it, it's likely toast*. The servos seem very durable. The grease isn't. I blame Porsche for using a grease that fails after 125,000 km, even if that use was spread over 14 years. My 2005 Lexus might have similar servos, but I'll likely never know. They keep working, just like the ignition coils on the Japan-built car. Regarding missing servos: I could only find one on the passenger side plate in my LHD car. No explanation from the manual. REMEMBER! Make sure all blue connectors are fastened to the servos before you put the plates back in place. *Electronic things run on smoke, I think. When the smoke is released, they don't work any more.
Great photography. You do realize that the three servos will come out as a unit if you remove the screws holding the aluminum plate in place? That's not easy, but it is do-able. Be sure to reconnect all of the servos before you put the plate back up in. I forgot to do one and lost a full day getting the plate out and in again.
Heidi: I found the manual above to be unreadable. Online -- on eBay, I believe, I paid a guy in India about $15.00 for an electronic copy of a Porsche Cayenne service manual. It took a long time and a couple of demanded refunds before he eventually came through with quite a usable manual, though entirely in PDF. Servos are on both sides. There were two on the right side, behind the glove box. They were pretty easy. There's one (on a left-hand drive) which is a sitting duck, right out in the open. I think it controls a flap. On mine there is another on a plate up in the bowels of the AC system. That's where I discovered the need for the long torx screwdrivers. One screw was a safety screw, even. That's a torx with a pin in the centre, accessible only to the bearer of a screwdriver with a centre hole drilled to go over the screw. I suspect it was inserted by an earlier desperate mechanic, because he had jammed it into vinyl, rather than the metal clip which is supposed to go over the vinyl. I found the clip below. BTW: a tiny light on the end of a long, flexible cable is essential for this job. After the right side I discovered further clicking on the left, so I spent the next couple of days jammed into the driver's floor. The left side was way more difficult than the right. I never bothered to disconnect the batteries. Ruby has two. Rod
The online manuals show the layout of the servos in chapter HVAC.pdf, from about page 35 on. These diagrams provide adequate information on positioning of the servos for re-installation. It doesn't matter where they are for removal. You can adjust the arms on your bench with a small 12v power source and a couple of leads. Contacts 1 and 2 can be teased to operate the servo motor. Reverse the contacts to reverse the motor until you have each in the position it's shown in the diagram. Then positioning of the servos becomes the least of your problems. Don't start the job without a set of long torqx screwdrivers and a tiny ratchet with assorted torqx bits. My experience in replacing the servos on a 2004 CS with left hand drive may not translate directly to a car with right hand drive, but I wrote about it at https://rodcroskery.wordpress.com/category/2004-porsche-cayenne-review (reverse chronological order September 18, 2016) and posted comments on page one of this discussion. I'm pretty sure you don't need any electronic equipment besides a multi-meter to change the servos from below. It's a gruelling job, though.
The online manuals show the layout of the servos in chapter HVAC.pdf, from about page 35 on. These diagrams provide adequate information on positioning of the servos for re-installation. It doesn't matter where they are for removal. You can adjust the arms on your bench with a small 12v power source and a couple of leads. Contacts 1 and 2 can be teased to operate the servo motor. Reverse the contacts to reverse the motor until you have each in the position it's shown in the diagram. Then positioning of the servos becomes the least of your problems. Don't start the job without a set of long torqx screwdrivers and a tiny ratchet with assorted torqx bits. My experience in replacing the servos on a 2004 CS with left hand drive may not translate directly to a car with right hand drive, but I wrote about it at https://rodcroskery.wordpress.com/category/2004-porsche-cayenne-review (reverse chronological order September 18, 2016) and posted comments on page one of this discussion.