While trying to find out how to connect to the different networks in my X350 through the OBD2 connector something I found a few things that are strange.

According to the Electrical Guides (2003.5/2004/2005/2006 en 2008) the networks are wired as follows at the OBD2 connector (IP39):

1 Not used
2 SCP Network +
3 Not used
4 GND (chassis)
5 GND (signal)
6 CAN +
7 ISO9141 K-line (Serial Data Link)
8 Not used
9 12V from Passenger Junction Fuse Box
10 SCP Network -
11 Not used
12 Not used
13 Not used
14 CAN -
15 Not used
16 12V Power

However in my OBD connector I see the following pin-out:

1 Emty
2 Present
3 Emty (I believe...)
4 Present
5 Present
6 Emty
7 Present
8 Emty
9 Present
10 Emty
11 Present
12 Emty
13 Emty
14 Emty
15 Present
16 Present

The X350 uses the ISO9141 protocol for OBD2 (called Serial Data Link) and the K-line only. This uses pins 4/5/7 and 16.

OBD2 also has a L-line which is normally at pin 15. I have the pin but (how) is it connected?

The SCP network seems to be present on pin 2 but strange enough pin 10 is empty. I could imagine that it's ground at the same point as pin 4/5 and therefore not connected.

And then there's the CANBUS. Not one pin connected?? And the X350 absolutely sure uses CAN.

And then there is pin 11 which is not mentioned in the guides. Should this actually be pin 10?

I have read the the Instrument Cluster serves as a gateway for the different networks so does one has to access the CANBUS over SCP (pin 2 and 10)?

In OBD2 there's also the J1850 PWM protocol which uses pin 2 and 10. Does anyone know if this is the protocol used for the SCP network?

Haven't done any measurements yet apart from regular OBD2 but would be very interested if someone has additional information.

Guus

 

pin 10 SCP should be there I think. You can't use GND because SCP is differential - the circuitry needs to compare SCP+ with SCP- and use the difference.

I can't see how 10 can be absent!

 

I found it....

Because I wasn't sure about pin 3 I had reasoned the pin-layout the wrong way round!

Looking at the schematic it's almost symmetrical and by switching the numbers left to right it's correct again!

Guus

 

obd2 no power having found fuse F43 Had blown i replaced it .When i switched the ignition back on the car wouldnt start even though the ignition lights on the dash were lit as normal. So i disconected the battery and rechecked F43 and F16 Fuses in the cabin fuse box reconnected the battery and the car started as normal with no issues but it still has no power to the obd2 code socket having tried two readers none would work help please

 

sorry forgot to say my car is a x350 v6 petrol

 

How are you determining a pin socket is "empty"? 6 and 14 are CAN bus and have to be there unless someone has ruined your OBD connector. Checking voltage or resistance will not give a usable result except for the B+ on pin 16 and the two ground pins on 4 and 5.

 

sorry but you have lost me there all i know is when i plug my reader into the socket niether will work ive tried them on a friends and they work fine im a bit reluctant to start pulling the wiring out so have booked it into mirfield jag speicelists to let them sort it only safe way to go i think but your help is apprieciated kind rgds Gordon