1fatskizz

Hey guys, first post, bear with me. My car just popped an engine light and the trans went into limp mode. Took it to the dealer and they're saying it's not communicating with their software at all? Has anyone had this type of issue before? The car still drove fine on the way down to the dealer, I'm waiting for their call but was wondering what info you guys might have.

By the way, nice to meet you all, wish my first post was a better one, haha. I have an 05 Cayenne Turbo, 84K all blacked out, nice looking ride. I hope to contribute to the forum in the future if I have a valuable info...

1fatskizz

I don't know if anyone's following this or not, but a quick update. They made communication, not sure how yet, but will post when I get the papers. It's a trans fault code, he's digging into it now. Will update when I know more. After talking to the service writer I'm finding out these Cayenne's are pretty finicky...

Andy E.

This happened to me on my '09 GTS. The problem was linked to a corroded CAN-BUS electrical connector underneath the driver's side carpet. A blocked sunroof drain during winter months froze/thawed/froze and flooded the floor below the carpet.

This is a known problem with the 955/957 Cayenne. It's worth taking a look...

1fatskizz

Noted, thank you!

Petza914

Andy,

Does the Pano roof have the same type of drainage system or is it different than Cayennes with a regular sunroof?

Pete

Andy E.

Pete,

The roof drains are different in both the sunroof and panorama roof but essentially, they both work the same way in that they exit through the same pillars.

1fatskizz

Official diagnoses came in as a bad TCU due to trans fluid soaking it and valve body. Dealer has quoted me $6K for the work, that's outrageous! I have a good indi shop putting together a quote on replacing the TCU and new plug, he's confident it will solve the problem. Worst case is a valve body to follow, any way you look at it, it will be a fraction of the dealer cost...

1fatskizz

Anyone have a write up on replacing the TCU? I can't seem to find one anywhere. From what I understand it's under the driver's seat?

Andy E.

There are firms that specialize in repairing ECU's. You may want to try reaching out to a few to see if they'd be able to diagnose and repair your unit. You can also start by physically opening the unit, removing all residual fluid and and air drying. Unlike water, most oils have insulating properties and if lucky, all it really may require is a good cleaning.

1fatskizz

I'm totally open to this idea, but I have no idea where it's at or how to get it. If I did, I'd take it out, blow it off or clean it and let it sit overnight. But I have to let my indi shop know before 4 today to order the parts because they have to order them in...

v10rick

The TCU is under the front passenger seat. Does your Indy have the PIWIS tester or equivalent to program the module? It has to be married to your vehicle.

1fatskizz

im in big trouble guys! I'm now being told, after replacing the TCU and wiring harnesses, that it now needs some sort of output shaft sensor that I can ONLY get by replacing the WHOLE trans??? Anyone?

Derek Tsang

XR4Tim

I don't know of any output sensors that require transmission replacement. I think worst case is one that is only sold with the valve body.

Travis

TCU lives under passenger seat (same place as the transfer case TCU) as mentioned though I don't believe it requires a visit to the dealer to marry the unit to the car.

There was a TSB published addressing replacing the TCU due to a hard shift in the earlier P!Gs. There are two ways to upgrade the firmware one is to go to the dealer and get new software is loaded. Other option is to buy a new TCU with the newest software and install. No PWIS required either way.

https://rennlist.com/forums/attachme...-shift-1-2.pdf