I just tried the mod to cut the 12V red wire going in to the control module for the variable power steering. The module is located behind the glove box at my LHD Xkr 2000. I like the mod and want to go further and see what can be done to make the power steering adaptable.

I have a question for those of you that have been working with the signals from the can bus. I don't want to use the OBD2 port since hopefully it will be a permanent installation so the OBD2 port cannot be blocked all the time. Rather I want to read the can signals directly from the can bus wires, using a can adapter with an Arduino or similar. Are there can bus wires accessible in the space behind the glove box?

Bump. No takers?

Best is to check the electrical guide. It lists the position of all the control modules as well as the pinout for every connector, including wiring colors. I assume you would want vehicle speed, rpm, etc, so best is to look for the ISO-9141 bus instead because this is where OBDII is implemented. As you know, OBDII is well documented. I am sure these same data points are available over CAN a well, but it may not be a easy to decode, i.e. not documented. Just my thoughts.

Thanks fmertz,

I have now studied the electrical guide and found pins 10 and 24 at the Major Instrument Pack that I believe are the CAN High and CAN Low signal wires respectively, see pictures below.
When you suggest to use the ISO-9141 bus instead, is that the same as the SCP network referred to in the electrical guide? I cannot find any information in the guide about ISO-9141. Since I plan to use an Arduino to build my solution and there are quite a few CAN Shields available for Arduino thats my plan A. The CAN messages for vehicle speed, throttle position and so on will require some work to log, that's true. CAN logging will be one of the first activities I need to to but one or two members at the forum have already done some of the work and created a crude list of messages.

In this car, there is CAN, SCP and Serial ISO-9141. From memory, it is the "S" symbol above, pins 13 and 14. For decoding, there is the ELM327 itself...

S stands for SCP Network and D stands for Serial and encoded

Are there ELM327 Shields like there are CAN Shields for Arduino that can be hard wired from the D-pin? I want to avoid using the OBDII port

ELM electronics has datasheets on their web site, including basic example wiring and command set.

For reading data Serial and ELM should likely be the easier way. But later on I might want to send messages over the network as well, messages that can be read elsewhere in the car. And sending messages to the serial, encrypted network maybe is out of question?

In case you use ISO9141, think what to do about the 510-ohm (IIRC) pull-up (you don't want too few or too many).

Thanks for the heads-up JagV8. My first option will be to go the Can route since I want to send messages as well. Besides, not all modules in the car are connected to the Serial encrypted network.

Not to pressure you into using the serial network, but I do not believe it is "encrypted" in any way. This serial network is also likely less critical to the operation of the car, so maybe safer for experimentation.

The various OBD types have checksums etc but none are actually encrypted.