Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
Thanks for all the help people! She now starts with the transmission control unit disconnected, obviously lots of faults lit up.
Going to check the wiring thoroughly from here. Can I check voltage or resistance on this module to rule out wiring issues? Guessing it will need coding if a replacement is required?
21st Apr 2014 10:34 am
TDi.Si
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
Right now I'm really confused! Re connected the module to defiantly make sure it was that, car started with no problems at all just tried it again after it's been sat about 3 hours and won't start again, disconnect the TCM and it still won't start!
I'm guessing it's a broken wire somewhere causing this? Guess it only makes a circuit occasionally. I've read that there are spliced canbus joints around the loom, does anyone have any pointers as to where to start looking?
21st Apr 2014 6:35 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20853
The splice joints are not in a specified location. Only in a general vicinity...
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Slightly more than a general vicinity as the numbers at the end of the wire descriptor is the distance between the two points in millimetres.
So if you find the connector and the next point is a splice then trace the wiring from the connector for 'x' mm to find the splice. If you have more than one starting point then you can triangulate the location with reasonable accuracy.
If you make a habit of reading the distance even when you know the location of the connector or splice you brain becomes reasonably adept at visualising where the joins are. This is handy for me as I am more thumbs than fingers when it comes to removing bits of trim without loosing all the clips.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 02 Jul 2006
Location: Oberon, NSW
Posts: 6922
Is the TCM in the engine bay behind the battery?
If that is the one they can fail due to water ingress. Check the connectors?“There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely gamesâ€
Ernest Hemmingway
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22nd Apr 2014 12:46 am
TDi.Si
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
All good advise so far! Thanks very much for those diagrams! I figure it must be a break in a wire which was disturbed when i removed the tcm. Yes it the one behind the battery, its clean and dry, i even took it apart to check inside for moisture, but its all good.
It seams im jinxed with cars, my VW has a electrical fault too, albeit it still runs fine!
22nd Apr 2014 11:22 am
TDi.Si
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
Im at a bit of a loss with this now. It seams as if the car will run after a hard reset for an un determined amount of time then the hazards come on and it lowers, it doesnt always cut the engine though! It then will sometimes start after its gone to sleep, or a hard reset will work, other times it wont reset atall!
Are those diagrams from topix? I may have to subscribe if so to get a clearer image.
Any suggestions are welcome as i really do like the car, but its looking ever more likey to be sold as a non runner
28th Apr 2014 7:02 am
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20853
Had a very similar fault. EPB module was dropping out of the canbus network, after the car was running for 90 seconds. Once whatever it was in the module had cooled down, it would restart againMy D3 Build Thread
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
I guess that would make scense! Ill have to time it, seams to be around 15 mins. Would it show up as a logged code if i was to scan it with a decent scanner?
28th Apr 2014 7:46 am
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20853
No, a scanner will not pinpoint the fault.
Disco_Mikey wrote:
No, comes down to good old fashioned diagnostics
You need to break down the CAN-BUS wiring into sections, and isolate them. If the wiring is all fine, then start isolating modules, one by one
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
So its a case of litrally unplugging the suspect module and running/driving the car to see if it cures it? Or is there a better way?
I dont mind putting the time in, just want to make sure ive got a rough idea of what to do.
28th Apr 2014 8:29 am
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20853
You have to isolate the module/wiring, and complete the canbus circuit, to allow the car to start My D3 Build Thread
Member Since: 09 May 2013
Location: Stroud, Glos
Posts: 101
Well it would appear to be a wiring fault. If I start the car car move the wires in the black connector behind the passenger side rear wheel it instantly lowers, hazards etc! Seam to be getting somewhere now!
Big thanks to everyone especially Disco_Mikey
28th Apr 2014 7:56 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Ah yes, a favourite place for wiring issues. I feel some heatshrunk crimp action coming.
Glad you found the source.
Land Rover - Turning Drivers into Mechanics Since 1948
One of the most reasoned and thorough diagnostic threads on here - this careful approach will always yield results in the end. This ought to be a "sticky" I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
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with the transmission control unit disconnected, obviously lots of faults lit up.
just tried it again after it's been sat about 3 hours and won't start again, disconnect the TCM and it still won't start! 
