Macster

Pins 8, 11, 12 , and 13 are all labeled "discretionary" in the SAE J1962 specification I have. (Same goes for pins 1 and 3. 4 is chassis ground. Pin 16 is permanent positive voltage.)

Do you see pin sockets in the pin locations of interest in the OBD2 connector? If no pin socket, the pin is not connected.

If there is a pin socket showing then the pin is likely connected but to what without access to the wiring diagram of the diagnostics connector of that particular model of car or access to a PST2/PIWIS/PIWIS2 for that particular model of car to reverse engineer what pins are connected and what they are used for...I'm unable to say what they are used for.

Mandated by I guess the fed gov. and some state gov. environmental agencies (EPA/CARB to name two) there is an OBD bus, generally for Porsches this is ISO-9141-2 but not always. (My 08 Cayman S was KWP2000. As the car was an 08 MY I was expecting CAN but my info is Porsche (along with other car makers) asked for and received a pass on switching to CAN in 08.) Newer model years might have switched to CAN. (My Cayman S had a CAN bus but this was the comfort (Komfort in Porsche speak IIRC) bus which in the case of my Cayman was used by Porsche test computer to communicate with the instrument cluster. (The communication was hard to follow -- I captured it with a bus snooping tool/software I have -- and gateways were involved. I captured this traffic to figure out how to clear/dismiss the service light (among other things) but when I lost my Cayman S shortly after this to an accident I lost all interest in doing this.)

Except for rpms (in the case of some Porsches at least) and possibly speed (VSS) -- which is manufacturer dependent -- the rest of the data I believe are only available from the engine controller using the OBD2 bus and a suitable communication protocol. At least this is the only way I've been able to obtain this data. But it is really the only way I care to.

Auto test equipment I have I use to read this info from a variety of vehicles all the time. Well, not directly except when I have an hand held OBD2 code reader/data logger connected to a car for this purpose.

More often and in a number of vehicles the data is read automatically and is stored for later retrieval via a USB or wireless connection or stored/sent at some later time via a cell phone link to a web site and there I can view the data. I can also interact with the car with the right software using this device/cell phone link and have in the car essentially a remote wireless scan tool.

Now at the car, your car, in other places there might be test points at some connection that with a proper break out box and details on its pin out these raw signals could be available and with the right electronics could be translated into human readable format.

But a wiring diagram is needed to know, unless you can find someone who's already figured this out.

If anybody has it would be my guess someone working for a company that offers data loggers/metrics gathering technology for say track cars. They would probably consider this info a business secret and keep it to themselves.

Sincerely,

Macster.

sjfehr

Depends what I'm doing. I've pulled rpm, throttle, engine load and speed for race logging, but I've also plotted/logged O2 sensors, MAF, fuel ratio and others for troubleshooting purposes.

FYI, I use a bluetooth OBDII similar to the one linked above to datalog with my cell phone. Works beautifully! Had to invest in an external 10Hz bluetooth GPS, as most phones only update about 1Hz which isn't very useful. Still, $25 for the OBDII + $80 for the GPS + $6 for the software is damned cheap data logging w/instant review. Awesome to finish an autocross run and be able to instantly review video with full telemetry!

Apex996

Red = TPS
Grn = RPM
Yel = Ign Adv
Silv= MAF

thirteeneast

+1

and I think thats universal for OBD