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Crankshaft Position Sensor on a Tiptronic

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Hi all,

Hoping to provide some clarity on replacing the crankshaft position sensor on a 986 WITH Tiptronic transmission as I have not seen (or was unable to find) any good/clear pictures of the process to find the sensor.  As I found out, it is hiding well behind the plug/receptacle for the Oxygen sensor on the right side of the vehicle.  I read all kinds of guides pointing me to the correct general location, but they all pretty much said it was obvious and I knew exactly what I was looking for.  I spent well over an hour searching because I could not see it, and found out that on a Tiptronic, you have no direct line of sight to the sensor unless you move the oxygen sensor plug/receptacle.  Hopefully these pictures will help anyone else trying to replace the CPS no a tip.


In order to see the CPS  you must unplug the oxygen sensor, remove the receptacle mounting bolt and push both cables and mount/receptacle out of your way.  The view shown here is from underneath the car looking up towards the wheel well and CV joint.


A wider view of the area you need to look into remove the oxygen sensor, receptacle, and bracket.  You can follow the cable from the oxygen sensor to the bracket in order to find it more easily.


This is your entry point and trajectory.  Just beside the right rear brake caliper, under the brake fluid line, past the coolant reservoir drain hose.  The extension is probably all of 18 inches to get you deep into where you need to be to unscrew the bolt holding the CPS in place.  I used the light you see plus a large work light on the floor to finally visualize the sensor.  The only way I was finally able to find the sensor was to identify the cable from the sensor and follow it by hand and light.  That is when I realized I could not see it due to the oxygen sensor plug being in the way.


This is just a wider shot of the entry using the light as a reference and the brake caliper is in the foreground.


Here is a view of the CPS still in place, but the bolt has been removed.  The oxygen sensor plug and receptacle have also been removed and pushed out of the way.  Once you see the CPS, it is obvious that is what you've been looking for.  What I think are coolant hoses are very close to the trajectory you need to access the bolt.  My extensions were pushed up right next to these hoses and I had to push on them with the tool in order to get access to the bolt.



Just a couple of other tips and tricks.  The bolt of the CPS is held on by thread locker.  Make sure you have good engagement with your male hex into the screw head during removal, otherwise it could strip.  I recommend ordering a new screw for the CPS while you're at it, the newer ones are torx and less likely to strip.  Once you locate the CPS you will find that you can actually reach in there with your fingers through a path in order to push it out of and into the hole.  When you go to put in your new CPS, place it in first without the bolt.  You can wiggle it into the hole reasonably easy with your fingers through the aforementioned path.  When you go to place the bolt, either use a magnetic tool or tape the bolt to your male hex so that it doesn't fall off.  Yours truly lost the original bolt and still have yet to find it.  Luckily it is a pretty standard M6x16 available at your local hardware store.  But I have no clue where that bolt ended up.  I searched by every means possible including a powerful magnet around the area of loss and still could not find it.


Hope this helps save you the hour or so of searching in your 986 Tiptronic for the CPS.  Remove that O2 sensor harness first and you'll save a bunch of time and frustration!


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I don’t know on a TIP if the same hole exists, but on a manual just below the cps is an access whole to the flywheel/clutch assembly.


I dropped the cps bolt and lost it too.  I ended up dis assembling the entire back end and removed the Tranny to find the bolt had roles back onto a ledge on the engine block.


it was just waiting to play pachinko with my flywheel.


turned a 15min job into a 2 day nightmare.


DYI tip, reach in there, feel for the hole and stuff a shop towel in there, so when your mag and tape plan fails, the bolt can’t find the hidey hole.



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56 minutes ago, crwarren11 said:

Yep I think that’s where mine is...I can reach a little into the hole but not enough to find it. Probed around with the magnet in there too as much as I could.


You will be the first to know if it is.  As Mike noted, once it comes off the ledge, it will make quite a racket, and could end up wiping out the CPS if it gets caught up in the shutters on the flywheel.

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6 hours ago, crwarren11 said:

Yep I think that’s where mine is...I can reach a little into the hole but not enough to find it. Probed around with the magnet in there too as much as I could.


Oh, I fished for that **** thing for a LONG time with a magnet -- to no avail.  Sorry to be the bearer of bad news -- but I don't think there is an opening in the bottom,

so once its in there -- I don't think its coming out (and that's not a good thing).


I think I have some pics on my phone -- maybe if you can see the possible locations -- you might be able to fish more productively.



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Whatever you might have would be greatly appreciated. 


As it turns out the CPS is not even the problem. The car still won’t start.  On to fuel pressure test next. 


Going to be very hard to swallow having to drop the trans for that bolt.  It sounds like you are telling me that I need to...


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16 hours ago, crwarren11 said:

Whatever you might have would be greatly appreciated. 


As it turns out the CPS is not even the problem. The car still won’t start.  On to fuel pressure test next. 


Going to be very hard to swallow having to drop the trans for that bolt.  It sounds like you are telling me that I need to...



I don’t have the picture that showed exactly where the bolt rolled to ... it’s in the other phone you can see in the first picture ?


but it you can see an example of the webbing it fell into.


so if you can get you magnet to go into the whole and then bend forward and check those crevices... you might have a chance.. you might consider borrowing a boroscope and see if you can locate it.


otherwise, my recommendation is to drop the tranny, which is what I ended up doing.  Murphy has never been a friend of mine when it comes to mechanical stuff... so I was pretty sure how all that was going to end up if I had left it there.





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5 minutes ago, crwarren11 said:

Thanks! I have a scope. I’ll see if I can find it in there! Didn’t even think about that.


Be careful, there is extremely limited room for something like a bore scope, even a very small one, and it is very easy to get the probe stuck.

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For years, shops like mine have tried to find an alternative method of seeing the IMS bearing cover on 2000-2001 and 2005 engines without having to take the thing apart.  We even brought in and evaluated "micro" scientific fiber optic camera probes that were on a few millimeters in diameter and cost more than $55K, none of them managed to get down far enough to see it without getting stuck. We never found a way to see the cover without taking the car apart.


I'm afraid you are on a "fool's errand" here.  Bite the bullet and pull it apart.

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1 minute ago, crwarren11 said:

Haha yes. Very likely. I’ll give it a few minutes while I chase the not-starting issue...and then sounds like I’ll be dropping the trans yet again.


As Mike noted, you are not the first one to get into this predicament, and you won't be the last.  Unfortunately, "fecal matter occurs" when nature sides with the hidden flaw.....

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In my case the bolt fell down and backwards into the hole, then managed to roll forward into the webbing of the engine -- it was in the first webbing just below the hole


if you can find a picture of the engine -- you might be able to try there -- not as tight quarters as trying to get down to the IMS.  I think it was along side the clutch, 

not behind it... but its been 4-5 years -- so I maybe mis-remembering.


In my case it was a royal PITA since I did my CPS in the driveway -- only to F it up -- and then had to trailer it to my buddy's shop to get it on the lift.


I never started it or even attempted to start it while it was in there.

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34 minutes ago, crwarren11 said:

Indeed Murphy loves me. As my wife reminds me, every time I do car work I drop/lose a bolt somewhere in the process. I think this is the first that has been in a dangerous place though. Yay!


Just remember: Murphy was an optimist...…………………...

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Are you guys talking about this hole? It's higher than the CPS though so how did the CPS bolt get into there?

I also include a pic of the webbing of the engine block in case it helps describing the location txhokie4life described.





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12 minutes ago, Ahsai said:

Are you guys talking about this hole? It's higher than the CPS though so how did the CPS bolt get into there?

I also include a pic of the webbing of the engine block in case it helps describing the location txhokie4life described.






If I remember correct - it was either where the pin to the chain guide (flip the yellow arrow), or the triangle just below it.

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  • 3 weeks later...

Finally got some time to work on this after replacing the fuel pump. There are really only two options. One is that the bolt fell forward and is lost on a rail or against a hose or something. The other is that is went backwards and there is only one possible location for it to end up based on the webbing on the engine side...See red boxes in the following images of the semi-circular cavity that goes directly into the area of flywheel and TC. In the image with the arrows I added a small “v” indicating the location of the bolt on the CPS, so one can see that by following from this point down, the bolt could only end up as stated above. In the image with the torque converter in place you can see that there would be space for the bolt to migrate into the area of the TC and flywheel. I did get my boroscope in that cavity pretty well and did not see anything. But I did not see enough to rule out the bolt being in there. I ran magnet through again with no luck. Anyway, just wanted to pass along my progress so far to see if there are any other thoughts. 





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  • 1 month later...

Hi guys,
Anyone have a good guide for tiptronic removal? Of course there are plenty for manual trans. I had a friend help me with this about ten years ago who knew all the tricks but he has since relocated. My Porsche manual isn’t very specific and references several special Porsche tools for locking torque converter position and several other things. I don’t specifically remember doing this last time but he was the one running the show that time around. I have everything out of the way and ready to disconnect trans from engine but don’t want to continue until I know everything else that needs to be done in advance. Thanks for your help!

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Take a photo of the top of the engine after all the covers are off

remove the rear bumper, you can just get at the screws under the rear spoiler with out taking it of

remove exhaust, i had to drill out the top 4 bolts holding the rear box. The bolts to the manifold i cut of with a chisel and small grinder

Remove drive shaft bolts

The two water pipes over the gearbox need to be removed as they drop down lower than  the cross member,remove the front engine cover to stop all of the coolant coming out, i used two wine bottle corks

Remove gear link from ball, i was unable to remove the outer cable from the gearbox mounting, so i left it on and moved it side ways when i removed the box


Top of engine

Remove the pipes,throttle body, clips and electrical cable, remember take a photo, a lot of pipes, 

I removed the oil air separater to remove the bottom starter bolt, as i had a new one to fit onto the engine

battery EARTH lead of, remove starter cables then starter

MARK the converter to the ring gear, so it fits back in the same place

I used a mirror to see the 6 bolts holding the torque converter  to the ring gear, you can turn the engine over by using a screwdriver on the ring gear teeth

When you have the 6 bolts out, leave the bolt on a magnet, so they will stay on the allan key when you refit them , also use grease to lock them on the allan key

With the 6 bolts out use a screwdriver to push the torque converter into the box and when you start to remove the box check the converter is coming out with the box

You will need a engine cross brace to support the engine.  GET a hose clip remover,       the pipes under the rear engine cross bar are in the centre of it  and the top one on the gearbox 







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Thanks for all of the advice. I am almost ready to move the trans. Coolant lines are clamped off but had to stop late last night at the point where I couldn’t easily remove the soft lines from the hard nozzles. The ring clamps are off but the lines are really sealed on there good. Once I get those off then I’m ready for the trans mounts to come off and the bolts connecting to the engine and then it should be freed. [emoji1696]

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