Ahsai

I figured that out from the 996 DME pinout diagram. What year is your Cayenne?
You need the pinout diagram of your Cayenne's transmission control module (under front passenger seat). I have the 2006 Cayenne transmission control module pinout:

- pin 45 Green/Blue oil temp sense "+"
- pin 8 Green/Gray oil temp sense "-"

The two pins are connected to the two-pin temp sensor inside the transmission. You can apply the same principles of my mod so you have to plot the voltage on pin 8 and 45 while reading the actual oil temp from Durametric then decide which pin to use.

knfeparty

Thanks a lot; it's a 2004 but I doubt it's different than 2006.

This project is on my long-term to-do list...definitely sounds fun.

ian_alex

I've just found this thread which seems to be exactly what I am looking for,however, I am not an electronics wizard so couldn't make the kit, fit it yes but thats all!
Has this ever gone into production as a kit?
Appreciate any replies.
Thanks

Ahsai

A kit would be nice but I have no such plan though. I agree it's meant for someone with some background and interest in electronics. I wish it could be easier but if you want an oil temp reading with fast response, the stock oil temp sensor in the oil sump is at a great location for that as the hot oil from the main/rod bearings drips back to the oil sump.

gnat

Awesome job man. Count me as another that can't believe they missed this before!

Now to convince the wife to let me modify her car. Maybe if I just show her the latest scored bore thread...

Spent 12 years blissfully ignorant of oil temps, but now that my 958 shows it in digital and analog formats it drives me nuts not being able to see it in the 996. The BMW has always pissed me off that you get neither the oil nor water temps

Ahsai

Thanks gnat. I think it's due to cost saving for 996.

Actually some bimmers are ok. A 2011 328i has the oil temp gauge front and center on the instrument cluster but it doesn't have voltmeter and coolant temp though. Btw, I measured the parasitic drain on that car and it was within a couple of mA (compared to ours tens of mA). No wonder their batteries last 6+ years. I guess their smart charging system pays off.

ian_alex

Ashai,
Thanks for your reply. I will investigate a stock VDO gauge with sump sensor.
Regards

Slakker

Ok, I'm finally starting to understand this. As a poor man's hack, could you take a 0-5 analog volt meter and relabel it with a sharpie? The strange part would be the needle would read backwards since 0=300F but for $10 it might be dang handy to have for track days.

Ahsai

Yes in theory because of the high impedence of the voltmeter. It won't draw much current from the dme.

However, the most interesting oil temp region is between 0 and 0.5v so unless you find a 0.5v voltmeter, the oil temp change won't move the needle much, literally.

Slakker

Lol. So much for that idea.

bartjan

Thus this one might work as poor mans hack?

Ahsai

Nope as the internal impedence of the analog voltmeter is too low. The DME won't be able to drive it from that oil temp sensor pin hence the digitial circuit I made.

Porschetech3

Or for a REALLY REALLY poor mans hack , you just wire in a small red or blue digital voltage display next to a small list of pertinent readings ie. .5v-220f .4v=225f .3v-230f ect.http://www.ebay.com/itm/3pcs-DC-0-30...-/281308807040

jdexter

Off topic, but since this data comes off the OBDII port, is there anyway to use one of the bluetooth OBD readers to pick up the data and send it properly? Why can the durametric read it, but my kiwi3 can't?

Ahsai

Two problems:
1) the data bus that allows the scanner to talk to the DME for this purpose is on a seperate pin than the regular OBDII pin

2) even if you can physically connect to that pin, the scanner still needs to speak the Porsche specific protocol (not OBD). It needs security authentication of the scanner before the scanner can even query the oil temp sensor value