Discovery 3 won't start

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First thing is to check the engine ground strap - easiest way is to use a heavy jump lead between the battery negative post & a good, clean bit of engine. I think the transmission fault message is a 'consequential' fault, not the cause of the non-start condition, it equally well could be a defective starter motor.

ETA - could also be the gear selector arm bushing on the transmission siezed - you wouldn't normally get any noise from the starter motor with that one though.
 
First thing is to check the engine ground strap - easiest way is to use a heavy jump lead between the battery negative post & a good, clean bit of engine. I think the transmission fault message is a 'consequential' fault, not the cause of the non-start condition, it equally well could be a defective starter motor.

ETA - could also be the gear selector arm bushing on the transmission siezed - you wouldn't normally get any noise from the starter motor with that one though.
Thanks so much for the response, yes i will defo try that, i do have some big jump leads knocking around.
 
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I don't think there's a start inhibit - otherwise the starter wouldn't click. If the initial checks are OK, then you need some way of reading the DTC's ('fault codes') to progress the diagnosis.
I've seen that message on other brands and later LR's but never on a L319!
 
I removed the battery and took the TCM module out, i took the TCM apart looking for any signs of corrosion but it looks ok, however there was some slight green discoluration on some of the plug pins. Im going to spray some contact cleaner on them later and clean them up a bit with a toothbrush before reinstalling. I tried earthing the engine block to the negative battery terminal with a heavy duty jump lead as you suggested but no good.
 
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The 'TCM' you've found is actually the Transfer Case Control Module - the 'true' TCM is integrated into the gearbox itself. It's possible its the transfer box that's throwing the transmission fault on the dash. Try putting the transmission into neutral with the ignition on and changing range a few times. Contact cleaner isn't corrosion remover so it may not be the cure you're looking for, the only real cure is to replace the connectors in the housing. I do think you're approaching the point of needing to read the DTC's to make progress.
 
The 'TCM' you've found is actually the Transfer Case Control Module - the 'true' TCM is integrated into the gearbox itself. It's possible its the transfer box that's throwing the transmission fault on the dash. Try putting the transmission into neutral with the ignition on and changing range a few times. Contact cleaner isn't corrosion remover so it may not be the cure you're looking for, the only real cure is to replace the connectors in the housing. I do think you're approaching the point of needing to read the DTC's to make progress.
One day I am going to find an electrical cleaner that actually cleans, all the ones I have used are a a disappointment.
 
They're all solvent based, of one sort or another. There isn't a solvent for copper corrosion...
The temptation is to use something abrasive, but that just widens the receptacle or thins down the pin. I've never found a better solution than replacing the corroded parts. I use www.auto-click.co.uk for stuff I can't get through work, sometimes you can resurrect pins on control modules with abrasive cleaning and a tinning coat of solder.
 
The 'TCM' you've found is actually the Transfer Case Control Module - the 'true' TCM is integrated into the gearbox itself. It's possible its the transfer box that's throwing the transmission fault on the dash. Try putting the transmission into neutral with the ignition on and changing range a few times. Contact cleaner isn't corrosion remover so it may not be the cure you're looking for, the only real cure is to replace the connectors in the housing. I do think you're approaching the point of needing to read the DTC's to make progress.
I cleaned the connections up a little and examined them under an electronic microscope and all looks fine. I do have an iCarsoft LR2 which i plugged in initially a few days ago but i didnt reallt understand what i was looking at, i do remember seeing a few faults with BCM if i remember rightly.
 
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It's the connections in the plug housing that will be problematic - watch out for a poor fitting battery box cover (or missing foam tape) that's the usual cause of water ingress - and a poorly fitted E-box cover!
I had two Disco 3's from new, the first, a 55 plate, was 'problematic' but was still on the road in November with 188k on it, the second, a 56 plate 07MY I had for sixteen years before passing it on to one of my sons - it's still in daily use. Over that time (and with a few years working in a LR dealer) I came to know them pretty well, driving them around the Artic circle, Alps, eastern Europe and North Africa. The only time I had any real problems were a rear wheel bearing failure driving through Spain to Morocco, repair was sorted out by LandRover Assist and we actually got to the RV point in Fes before the rest of the vehicle who'd detoured to Tangier for 'tourist' reasons!
 
One day I am going to find an electrical cleaner that actually cleans, all the ones I have used are a a disappointment.

Must confess when I found a few green terminals on a some connectors I very carefully used the files to clean the pins , along with using the spray , they came up a treat and tested them after with a multimeter to ensure Vdc was going through the connector

Hope it’s also useful to u

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It's the connections in the plug housing that will be problematic - watch out for a poor fitting battery box cover (or missing foam tape) that's the usual cause of water ingress - and a poorly fitted E-box cover!
I had two Disco 3's from new, the first, a 55 plate, was 'problematic' but was still on the road in November with 188k on it, the second, a 56 plate 07MY I had for sixteen years before passing it on to one of my sons - it's still in daily use. Over that time (and with a few years working in a LR dealer) I came to know them pretty well, driving them around the Artic circle, Alps, eastern Europe and North Africa. The only time I had any real problems were a rear wheel bearing failure driving through Spain to Morocco, repair was sorted out by LandRover Assist and we actually got to the RV point in Fes before the rest of the vehicle who'd detoured to Tangier for 'tourist' reasons!
That sounds amazing mate, and i will definitely be listening to all your advice. You obviously have a wealth of knowledge about these that is invaluable to novices like me. I'm very intrested and keen to learn all i can Graculus.
 
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