My Transfer Case is STILL Dead. Last Try.

[bobinyelm]

I started this "project" with about a dozen DTCs that plagued my new-to-me '04 Cayenne (that has turned out to actually be a 2003 according to the build date).

 

I replaced an after-cat O2 sensor to try to cure a "Cat Low Efficiency" DTC (P0431), so I will assume on that one is a genuinely tired Cat at 136k miles.

 

The other codes have all disappeared with a new Group 95 Battery,/H9 (vs the Group 49/H8 the last owner installed and which was at only around 11v ignition ON and not running) except for a level sensor I am awaiting a replacement I ordered.

 

The LAST "BIGGIES" are DTCs for the Transfer Case, DTCs for "Power Supply" and "Grounds" for Transfer Box Servo Motor DTCs 2040 and 2041.

 

I pulled ALL fuses and checked for corrosion and put them back, and checked for voltage at BOTH sides of every fuse. No problems. All wiring harnesses look great-no signs of physical damage or corrosion anywhere

 

I surrender...

 

Anyone offer a FINAL Hail Mary before going to the Porsche Dealer where they have a Test Box for the transfer system?

[lewisweller]

1 hour ago, bobinyelm said:

I started this "project" with about a dozen DTCs that plagued my new-to-me '04 Cayenne (that has turned out to actually be a 2003 according to the build date).

 

I replaced an after-cat O2 sensor to try to cure a "Cat Low Efficiency" DTC (P0431), so I will assume on that one is a genuinely tired Cat at 136k miles.

 

The other codes have all disappeared with a new Group 95 Battery,/H9 (vs the Group 49/H8 the last owner installed and which was at only around 11v ignition ON and not running) except for a level sensor I am awaiting a replacement I ordered.

 

The LAST "BIGGIES" are DTCs for the Transfer Case, DTCs for "Power Supply" and "Grounds" for Transfer Box Servo Motor DTCs 2040 and 2041.

 

I pulled ALL fuses and checked for corrosion and put them back, and checked for voltage at BOTH sides of every fuse. No problems. All wiring harnesses look great-no signs of physical damage or corrosion anywhere

 

I surrender...

 

Anyone offer a FINAL Hail Mary before going to the Porsche Dealer where they have a Test Box for the transfer system?

Yeah get under the passenger seat and whip out the control module. (You will find the transmission and TC module under there in a plastic cassette type case thing. Check part number of each and that will tell you which one is the TC, part number 0AD927755AB or similar IIRC, can't remember what the differences was in appearance though. 

Check the plug and harness for damages ( the harness can get trapped in the seat mechanism!) and then crack the control module open and check the board for fried components, bulging capacitors or anything obvious. Take pictures!!! Post them!!!  Don't be scared off by scaremongering people that say "oh you can't open them little black boxes of witch craft, the world will end". Ha ha 

 

Read the pdf attached for testing for faults codes 2040 and 2041, it looks as though the consensus is if not for a wiring issue/fuse blown, then either the servo motor or the control module is faulty.

Used control modules on Ebay are cheap as chips like £30 and they don't need to be programmed to your car it is plug and play as long as you buy another module with the same part number of the same manufacture year etc so I've been reliably informed and read. 

 

After that throw hands up in the air and reach for the wallet. 

TRANSFER BOX.pdf

[Brett968]

You might also want to pull the transfer case motor out and take a look at it. Takes like 10 minutes. As I recall, it is really easy to open the motor and inspect it once you have removed it from the car. On my Cayenne a winding on the stator had melted, rendering it inoperative.

[bobinyelm]

1 hour ago, Brett968 said:

You might also want to pull the transfer case motor out and take a look at it. Takes like 10 minutes. As I recall, it is really easy to open the motor and inspect it once you have removed it from the car. On my Cayenne a winding on the stator had melted, rendering it inoperative.

 

Curious-

 

Did it have any DTC codes you could pull before you looked and saw that it was physically toasted? 

[Brett968]

22 hours ago, bobinyelm said:

 

Curious-

 

Did it have any DTC codes you could pull before you looked and saw that it was physically toasted? 

I don't recall. It's been a few years. Sorry...