Tiptronic emergency run mode

[roadsession]

Apologies for the xpost but realized most naturally aspirated 996 have 6MT and many turbo owners seem to have tips....and the 722.6 transmission is shared...so here goes:

My car is in the shop with the following faults from the durametric:

DME: P0715 Porsche fault code 552 Tiptronic supply voltage speed sensors

Tiptronic: 13 RPM Sensor N3

transmission definitely hunts from 2 to 3 to 4

Transmission fluid level is ok, and it was changed 5,000 miles ago.

Dealer is saying it could be TCU or valve body.

I don't want to go through a $5,000 trial and error - what are your thoughts? in your experience which has been the most likely culprit of the two?

Thanks

[Loren]

Exact model year of your car please? (there is more than one Tiptronic)

[roadsession]

Exact model year of your car please? (there is more than one Tiptronic)

Hi Loren

It's a 2002 996 C4 with the mercedes 722.6 transmission...

Thanks!

[Loren]

P0715 Supply voltage of speed sensors (outside tolerance)

Possible cause of fault

- Short circuit to B+/ground/between wires or open circuit

- Tiptronic control unit faulty

Have you tried resetting them? (if it will let you)

If that is not it there is a several page troubleshooting for the Tiptronic wired connector that involves reading the connectivity of several wires - if you are up to try that I can send it to you.

[roadsession]

P0715 Supply voltage of speed sensors (outside tolerance)

Possible cause of fault

- Short circuit to B+/ground/between wires or open circuit

- Tiptronic control unit faulty

Have you tried resetting them? (if it will let you)

If that is not it there is a several page troubleshooting for the Tiptronic wired connector that involves reading the connectivity of several wires - if you are up to try that I can send it to you.

Hi Loren,

Thanks - yes it's been reset 2X and keeps coming back. i also reset adaptation. battery is new, ignition switch is new....

Is the 715 caused by the faulty RPM sensor in the valve body or is the RPM sensor not responding due to faulty TCU?

Thanks

[roadsession]

P0715 Supply voltage of speed sensors (outside tolerance)

Possible cause of fault

- Short circuit to B+/ground/between wires or open circuit

- Tiptronic control unit faulty

Have you tried resetting them? (if it will let you)

If that is not it there is a several page troubleshooting for the Tiptronic wired connector that involves reading the connectivity of several wires - if you are up to try that I can send it to you.

and yes if you can send it to me that would be great. I'm at roadsession at gmail.com

[Loren]

I sent it to you via PM.

[roadsession]

The problem ended up being the solenoid on the conductor plate.

The SA did say it's extremely rare to see a TCU go bad - for this fault code it's most often the solenoid/speed sensors on the conductor plate on the valve body.

It's all fixed.