alex_pescaru wrote:

Just a thought: connect the tester - its CANL and CANH, with the help of some wiring adaption - on the Haldex connector.
If you can read all other modules on the high speed CAN bus, then the wiring is OK and all problems are on the Haldex electronics.

The unit derives power from the USB side. In theory you need CAN-hi and CAN-lo and ground. In practice I don't bother with ground. The device just sits on the bus quietly reading all the messages.

I work with industrial PLCs and have to generate the code that sends commands, and reads messages from devices on the network - pressure sensors, motor controllers, etc. it's handy if the message sent by the PLC is actually what I meant to send. This allows me to check.
An old adage is a PLC (or computer) will always do what you tell it to do, which is not always what you wanted it to do

Click image to enlarge

Something like that would be ideal, but I guess outside the price range for an end user. I was looking at USB scopes, however it would need at least two channels and preferably a differential function. ----------
Tony S

aesmith wrote:

Do you reckon the tester would work with just power, ground and the high speed Canbus connected? The diagnostic socket also has the low speed CAN and some other connections.

Tony
You might have already seen this and done it whilst checking Canbus resistance.


If you measure from the Rear Diff connector, a little wiggle test may help find exact wire position that fault is. This seems a relatively easy way to nail fault IF it is wiring or connector.
Ian

PS quote from postings on this video.
By observing the network codes generated you can sometimes narrow your search down, but as I recall in this case once the meter was set up I just began wiggling and moving the looms and connectors until I saw an issue. I knew from the history of the car and the codes it was a network fault, this test just pinpoints where the issue was. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

This is the wiring diagram for HS CAN. ( on page 8 )
https://www.freel2.com/gallery/albums/user...TS_LHD.pdf

From what I can see there is a spur at S4DB05c/S4DB04c from the main harness to the RDCM connector. The fault should lie in this area (IF wiring/connector) as rest of CANbus runs in either direction from this point. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

IanMetro wrote:

Tony
You might have already seen this and done it whilst checking Canbus resistance.

IanMetro wrote:

From what I can see there is a spur at S4DB05c/S4DB04c from the main harness to the RDCM connector. The fault should lie in this area (IF wiring/connector) as rest of CANbus runs in either direction from this point.

Tony
I am afraid that my transmission line knowledge is although good, a bit ancient.
To test and identify any wiring faults I would have used a TDR (Time Domain Reflectometer.
This will show up any mismatches or circuit problems and, more importantly, its position in the cable.

http://canlist.vector-informatik.narkive.c...-condition

Inspecting and moving wiring looms is quite important in finding faults, dont forget a close inspection of any connectors for corrosion or movement (including pins).

Try googling 'CAN bus TDR', for clues what a 'modern' equivalent is to TDR.

Ian

PS Sorry if you have already said, but have you checked that you have correct power at the Rear Diff connector, both voltage and earth? (also to vehicle metalwork <earth>) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)