Tiptronic "reduced driving" mode - safe?

[Keggers]

I have a 1998 996 tip.

Just had an engine rebuild and when the engine went back in the transmission control unit has blown I think when the transmission speed sender was unplugged/plugged back in).

The D and 4 lights are flashing showing its in Reduced Driving mode and it still drives finen auto mode. My mechanic is ordering in a replacement control unit, but says its fine to drive it in the mean time. My only concern is whether there is any risk of damage to the transmission given that I understand the control unit controls the Tiptronic coolant shutoff valve. Does this default to open (in which case I assume the transmission will be cooled fine) or is there a risk the transmission will be getting no coolant without the control unit operating?

Thanks for any help.

[Richard Hamilton]

It is fine to drive it in the emergency program. Here's what the 99 SIT says:

Edited January 15, 2012 by Richard Hamilton

[Keggers]

Brilliant. Thanks Richard. That's exactly what I was hoping for. That last bit from the manual re it being completely safe is missing from my 1998 manual, but that has put my mind at ease. Am a bit paranoid after my engine went!!

[scottiemac]

My 99 Tip went into that mode a couple of years ago and the dealer said it was likely due to not keeping the battery fully charged. They reset it for free.

The same thing happened a while later and I plugged in my OBD tool, cancelled the fault, went right out and got a battery tender and it hasn't happened again.

[Keggers]

My 99 Tip went into that mode a couple of years ago and the dealer said it was likely due to not keeping the battery fully charged. They reset it for free.

The same thing happened a while later and I plugged in my OBD tool, cancelled the fault, went right out and got a battery tender and it hasn't happened again.

Hi scottiemac. Actually tried to find a fault with my durametric but it can't even find the tip control module, so I think the unit has actually gone unfortunately. Thanks for the tip though.

[Loren]

My 99 Tip went into that mode a couple of years ago and the dealer said it was likely due to not keeping the battery fully charged. They reset it for free.

The same thing happened a while later and I plugged in my OBD tool, cancelled the fault, went right out and got a battery tender and it hasn't happened again.

Hi scottiemac. Actually tried to find a fault with my durametric but it can't even find the tip control module, so I think the unit has actually gone unfortunately. Thanks for the tip though.

Find someone with a PST2 or PIWIS to check for faults.

[Keggers]

Ok, I'm now a very happy man. After scottiemac's post I dug the durametric out again and tried with version 5 rather than 6 software this time. It found the tip unit and a "tip unit to dme" fault. I reset the fault and bingo, problem solved. All is good again. Thanks very much scottiemac!!!

[scottiemac]

Cool. I've heard on these forums that these cars are very sensitive to battery charge. If I'm not going to use mine for a while I plug in the battery tender and it seems to work great. My 5 series BMW is similar.

Good luck with it.