Papagut

Just like it sounds - seems like my transfer case is locked up. I suspected the actuator, so I replaced it. The LED on the selector indicates reduced mode when I start up, if I put it into neutral and on the brake and attempt to turn reduced mode off, it will flash like it is attempting the change, then I get a 4WD error on the dash and the selector becomes inactive. Like it is attempting the switch, but fails. No sounds that I can detect from the actuator from within the car. When I was replacing the actuator, the there is a divot in the sprocket that did not line up, so I connected it and turned the ignition on to advance it into the correct orientation to install. That worked, making me think that the actuator is fine and it is some kind of mechanical lockup inside the transfer case. Changed the fluid, didn't look terrible, appropriate volume came out. Nothing warned me this might happen like any grinding, bumping or other funny business. Codes that seem relevant are: 2050 for mechanical switching error, 2039 potentiometer short circuit, 2033 potentiometer 2 short. There are others: DME control module 1314, and on occasion I am getting intermittent PSM failure light on the dash as well. Next suspicion for me is the module, or potentially corrosion in the wires coming to and from the module under the footwell passengers side carpet - I have seen this in the past for causing other random issues in this vehicle. New battery in it from just a few months ago. Anyone here seen anything similar or have any suggestions? Thanks - Mark

I'm going to chime in with my solution here just in case someone experiences a similar issue: I started with replacing coils and plugs in the cylinders that were misfiring as I wanted to rule that out. Simple solution really - almost all of the codes cleared up, starts and runs much more smoothly. I was not aware that warming up has an effect on coils/plugs - so I suppose I learned something there. Good luck if you run into the same issue. Mark

Good morning, here is my challenge with my 2004 high mileage Cayenne Turbo: on initial startup, I get a very rough idle that will settle after a minute or two, after the typical start-up cycle, although it will remain a bit rough afterward as well. I ran my codes and came back with these: P0199 - engine oil sensor (more on that in a moment) P0021 - cam position timing over advanced or system performance B2 P0431 - catalyst system efficiency below threshold bank 2 Plus misfires on 1, 3, 4 P0446 - evaporative emission vent control implausible signal I cleared these and ran again for a while, P0021, P0431, and P0199 came back more or less right away. I have had a rough idle in the past, so I checked the various vent lines again + the air oil separator gasket - all look sound, and all have been replaced somewhat recently as well. However, because the codes are all coming from one bank, my thinking is more toward the cam on bank 2 now: maybe the camshaft position sensor is at fault or variable timing solenoid is a bit gummed up. I checked the angles and found bank 2 has a deviation of 3 degrees, not sure if that is significant enough to come into play. Raising the RPM and watching the angles in real time seemed to show the cams responding and adjusting evenly and in step with one another. Also not certain if the O2 sensors on that side are feeding poor information, but not getting any codes indicating that. Finally, the oil sensor is definitely gone, I have a new one ready to install on my next oil service, which is coming up pretty shortly. This behavior predates the sensor failure, but has been getting worse lately. Plugs are fairly new, coils I checked as well when I did the plugs. The general feeling of vibration I get from the warm engine I am chalking up to aging engine mounts, which have never been replaced to my knowledge. Any insight you might have to share on what may be the source of my codes would be greatly appreciated. Thanks, Mark

Great news! In my cayenne, I found wiring in both sides that was corroded, but only those wires that you were holding were corroded completely and causing my major problems. Nothing found in the back for me, and no moisture traveled that far, just drivers and passengers side front. Perhaps some of the other errors you are seeing are persistent and you just need the faults to be cleared? You may just need to drive it around a bit. I'll pass along one more related tip that has helped me out quite a bit for my electrical issues: under the carpet in front of the drivers side seat is where the battery grounds to the frame. If you are getting some moisture in the footwell carpeting, I would inspect that too for any corrosion and clean it up for a nice connection. I put some conductive grease on mine. I do that once a year or so where I am because we have wet snowy winters and use salt on the roads and that main connection is right about where your wet feet go. Glad to hear you have it mostly sorted out. Good luck, Mark

In my opinion you have absolutely found the source of your troubles. The symptoms were the same, and your picture may as well have been one I took myself. There were no wires in my harness that were left with an intentional dead ends, and I can even remember that particular wire being in a similar state. Mine had corroded away entirely just like the wires you are holding. I remember both times the wires terminated in a larger connection in my car, but mine is a 2004, so potentially different. Were these two lines the only two inside some tape that you have cleared away? If they were clearly the only two inside the tape - then most definitely, clean them up and reconnect them. I would be willing to bet that your systems will all come back up. If you found them just like the image, naked and loose inside the bundle of wires, then I would be careful to search for their original near connection points. It is a little harder to see in your image, but behind your finger looks like a connection for a number of larger wires wrapped in electrical tape? I would inspect that too while you are in there. Another thing: right behind your thumb on the left on the thinner of the two wires looks like more corrosion maybe? Watch out for that, you may reconnect everything perfectly but there may be more corrosion further up the line just waiting to cause more trouble. When I was doing mine I just felt the flexibility of the wire for any signs. So, 100% I think you have the problem right there inbetween your fingers, just be careful that you reconnect them back the way they were originally, then afterward get the wheel wells off and clean out the drain points that tend to clog up and cause water to get into that area. Write me back if you want more info on that and good luck! Mark

I have a development to share: after nearly 10 years, this same set of symptoms suddenly returned for me: brake proportioning, PSM, ABS, speedometer - all offline + can't put it into gear. I went straight to the same place that caused me trouble all that time ago: drivers side, under the carpet, right about where the footrest is, and exposed the wiring harness. Of all the reconnections and cleaning up that it did - there it was: one small power line had become corroded and broke loose. Cleaned and reconnected, all systems immediately back up. I'm not saying that there are not other causes for this trouble, but only posting this in the hopes that I can help another member out. Here is a post-repair picture, the red lines you see looping back upward in the centre of the image - those were my culprit. The thinnest of them had come loose. Hope that this may help someone out.

Just in case anyone comes across this thread trying to solve unstable idle issues, bigbuzuki was on the right track. I replaced the vapor canister purge valve, pretty easy and inexpensive, and the crankcase breather check valve, even easier. the purge valve may have been a contributor, but the check valve was the main culprit. What is interesting here is that all of my ventilation hoses were intact and without leaks, but if you peered inside the removed check valve, you could clearly see that the membranes inside had completely disintegrated. That immediately did the trick.

I am thinking this is definitely a likely cause too. I replaced the ones running over the top of the engine a while back, they are all nice and intact, replaced the air-oil separator gasket, that has a nice seal now too, but the line that runs downward on the drivers side front of the engine - that is where I will look next. I think I will start a new topic specific to my idle issues with the codes that I am getting.

Thanks for that information, I'll check that off my list of possible causes for my unstable idle issues.

I just removed and cleaned my throttle body as a step in trying to get a nice stable idle, and I noticed that at rest, the plate is slightly open. Here are a few pictures to illustrate it - is that a normal state? After cleaning it, and it was moderately soiled, I also attempted to reset the adaptations via Durametric. Following the instructions, it says that once completed, the final value will read 14 - mine started at 11, and after following the process - ended right back at 11. Not sure if that is related so I thought it best to note that too. No other significant errors present. Thanks, Mark

So, in the end I never got to try this solution... There was a HUGE storm in Calgary, flooding everywhere, and I was caught in it. I had to drive through mabye 24" of water at one point. It was something else! Anyhow, I park it for the evening, and when I go to fire it up the next morning - problem solved! Something obviously happened on that trip that caused it to reset in some way - but as soon as the back end dropped, it returned to level and is functioning normally. So, if you find yourself in the situation I did, I would definitely try bleeding off some air like wrinkledpants and paqueras are suggesting before replacing the module or valve body, which are pretty expensive. Or of course, just drive into the nearest lake - that clearly seems to work! Thanks, Mark

Strangely, I was wondering about giving that a try - I have the cover off at the compressor and will give it a shot and post back

Hi, I have an interesting issue: my front wheels will adjust ride height, but my rear wheels will not - they are stuck in the highest position. When I start it up, I can hear the system attempt to raise the back end further, but since it is at it's maximum, this causes a system error eventually that locks out any manual adjustment. I suspect that this started when I did an extended job on this car and the right rear had a slow leak in the system someplace, and eventually dropped down to a very low position. What I thought I would find is that the height sensor on that corner may have broken - but no, all looks fine (sensors at all corners look fine). When first start the car, the height adjustment is active momentarily, and if I adjust it, the front wheels will respond - the rear wheels will not. My first instinct was to calibrate with Durametric, but that requires the suspension to be in the normal position, and I cannot get there with my back end stuck way up in the air. It is as if air can enter the rear end but cannot escape, or that the vehicle believes that the rear end is in a lower position than it is in reality. Any suggestions on how to proceed? Thanks, Mark

Hi everyone, I have a slow oil leak happening at the far front drivers side of my 2004 Cayenne Turbo. I have it down to a fairly small area, but am not sure about the likely source as the whole area is a bit fouled up. Would you let me know what you think would be a likely source? I lose about 1 litre over maybe 6-9 months. First image is from inside the left wheel well looking forward, second and third images are from underneath the same location from different angles. Thanks, Mark

Thanks, I am sure it is a break in the signal someplace, and there are plenty of modules under the passenger seat along with another in the cubby, which doesn't look like a typical amp to me - but I am going to have a good search for that connector. When I pulled the head unit, I had a good look at the connector. The thing is, I cannot seem to locate that same connector or set of lines anywhere else. Well, not immediately apparent anyhow. Would you expect it to be bundled within a wiring harness along with standard wiring? I'll post back with what I find.