2012 Cayenne transmission fluid change and now only has 3rd gear!

[GiftedFew]

Hello all, I just changed out my transmission fluid and filter on my 2012 Cayenne S.  Relatively straight forward job that took a few hours but when I started the truck, the check engine light came on and only has 3rd gear when I put it in drive.  I followed the steps on heating the fluid up to ensure the proper amount of fluid level is reached.  

 

When put it in gear it goes right to 3rd gear and will not shift.  

 

Reverse seems fine it is just when it is on drive.  I tried putting it in manual mode and that will not do anything.  Hoping someone can help! 

[GiftedFew]

Update:  It appears to be a trouble code P0700/$07E8 - Transmission control system.  

 

I tried resetting the code, but it did not do anything.  It still stays in 3rd gears only when in drive. 

[JFP in PA]

You need access to a Porsche specific scan tool to go further.  P0700 Indicates the powertrain control module (PCM) detected an error in the vehicle speed information.

[GiftedFew]

Thanks JFP, there is now a new code P0796 Pressure Control Solenoid C Performance/Stuck off

 

Seems odd these codes came on after a fluid and filter change.  It stays in 3rd gears so looks like it will need a tow.

 

Is it worth removing the pan again to see if there is some sort of damage to wires in the transmission?  Everything looked good when I put it back together but maybe something happened.  

[RFM]

Did you put the O-ring on the new filter and is it o.k ? 

[GiftedFew]

I did put the O-ring on the new filter and just confirmed this morning that the old filter has the old O-ring as well.  So, there is not two O-rings causing the issue.

 

I think minimally I will remove the pan again this weekend and see if I can visually see anything wrong.  Is there anything specific I should look for?

[GiftedFew]

Heading out to pull the pan and inspect the wiring! Hoping to find something obvious.  

[JFP in PA]

26 minutes ago, GiftedFew said:

Heading out to pull the pan and inspect the wiring! Hoping to find something obvious.  

 

Unfortunately, a stuck or dead solenoid looks exactly like a brand new one right out of the box; the problem is internal. 

[GiftedFew]

JFP you are right, everything looks good. there is nothing loose.  I did find out the reason for 3rd gear is it is the only gear that does not need power hence its the onloy gear that is working.  Any ideas how I would check for power to the harness? 

[GiftedFew]

here are photos of the harness.  

[JFP in PA]

I would be willing to bet you already have power to the harness, otherwise you would be getting an "open circuit" code, which you do not have currently, and the vehicle has gone into "limp mode".  The code you are getting is pretty specific, the solenoid is not moving when it should, which also implies power in the system.  You have a jammed solenoid, which needs replacing.  When one jams, it is a good idea to replace them all, as one usually follows the others.  A full set (aftermarket) retails in the $400 range, plus labor and fluid. Just be aware Porsche does not sell solenoids by themselves, they will tell you that you need a new transmission.  Most aftermarket shops simply replace the entire valve body with solenoids with a rebuilt unit with new solenoids, ($700-800 for the unit) which usually fixes the problems. 

 

Ninety-nine times out of one hundred, problems like this result from Porsche's ridiculous tip oil service intervals; the trans should get fresh fluid and a filter at least every 45-50K miles.

 

Overview of wiring harness

-1- - Shift solenoid valve (S1)

-2- - Plug connection for output shaft speed inductive pickup

-2a- - Cable routing for output shaft speed inductive pickup

-3- - Oil pressure switch 2 for transmission (omit in MY 2006)

-4- - Oil pressure switch 1 for transmission (omit in MY 2006)

-5- - Shift solenoid valve UK (modulation pressure)

-6- - Input shaft speed (turbine speed) inductive pickup

-7- - ATF temperature sensor

-8- - Modulation pressure solenoid valve (main)

-9- - Shift solenoid valve C1 (modulation pressure

-10- - Shift solenoid valve C3 (modulation pressure)

-11- - Shift solenoid valve B1 (modulation pressure)

-12- - Shift solenoid valve C2 (modulation pressure)

-13- - Shift solenoid valve (S2)

[GiftedFew]

ok, Thanks so much for the insight, super helpful.  I will call a few local shops on Monday and see if anyone can handle the repair.  

[JFP in PA]

2 minutes ago, GiftedFew said:

ok, Thanks so much for the insight, super helpful.  I will call a few local shops on Monday and see if anyone can handle the repair.  

 

Consider becoming a contributing member and donating to RennTech, it cost a lot to run this site and maintain access to a library of technical information like we do 😉

[GiftedFew]

will do, i get it on the maintenance.  If i pull the body valve and replace it.  is it a plug and play or is there programing required?

.

[JFP in PA]

It should be a direct "plug and play" swap, as nothing inside the Tip is programable, all that stuff is outside in the unit's control module.  The trans will probably have to go thru an adaptation relearn afterwards, but that just requires a "reset" not unlike zeroing the trip odometer.  Most Porsche scan tools can handle it if it is required. 

[GiftedFew]

I received the new valve body today, installed it, went together pretty easy.  Plugged in all wiring harness wires, replaced the filter (one o-ring), re-installed the pan and filled it with fluid per directions at Blauparts.  It has the exact same issue, 3rd gear only.  The transmission gear lights on the dash is blank for park, reverse, neutral, it lights up in drive but only 3rd gear.   I'm at a loss, it is still giving the same codes.  I erased the codes and still the same, then when i turn it off and back on the codes are back.

 

[JFP in PA]

Did the valve body come with all new solenoids? 

[GiftedFew]

It did and said it was tested and operational. 

 

[JFP in PA]

At this juncture, I would say you need access to a PIWIS system to properly test cycle the individual components, as well as evaluating the transmission's external control module.  

[GiftedFew]

Looks like I will need to take it to a shop.  hoping one near me can handle that. 

[JFP in PA]

26 minutes ago, GiftedFew said:

Looks like I will need to take it to a shop.  hoping one near me can handle that. 

 

You need to make sure whomever you choose has a current PIWIS system, the late model Cayenne's use a different control system than earlier Porsche's, making them a bit of a pain to run diagnostics on without the PIWIS. 

[GiftedFew]

JFP, do you know where I can send the valve body to have it refurbished?  The one I bought was from ebay and it said it was in working order but maybe it was not.  I have been searching around and even called Revmax but they don't do them anymore.  

 

I'm dropping the car off at a shop today so they can run diagnostics.  They have a current PIWIS system that they are going to use. I have a feeling they may tell me its the valve body and the one from ebay was just bad.  

[JFP in PA]

2 hours ago, GiftedFew said:

JFP, do you know where I can send the valve body to have it refurbished?  The one I bought was from ebay and it said it was in working order but maybe it was not.  I have been searching around and even called Revmax but they don't do them anymore.  

  

 

Not really; you might try checking with your local chapter of PCA for members that have gone thru the same issues.