V8 Discovery 2 won't start means

So, @ManxDisco ... how did you get on?

Well when fault last occurrd I did not get the symptoms described by Dippypud. Ie no dash leds once in possition 2. I think the fault may be more prevalent when the battery is at 12.3volts or below. I have recharged the new battery and the fault has not reoccured since Sunday night.
I spoke to CallRover today and he advised that I wiggle the wIrini on back of ignition switch next time it fails. Then if this does not work replace both fuse boxes. This ties in with Sierrafery's thinking. Alternatively it could be a fault that occures every time my wife considers driving or being driven in the car .
I have ordered some circuit board silicon spray from Radio Spares as Nanoroad would not accept paypal. In any event this intermitent problem does not worry me so much knowing that I can hot wire it.

The Discovery ran fine all week - even wading through 2 ft of flood water without any problems.
We did a good run in it on Friday night then Saturday morning when I went to move the Disco - would not start - same symptoms. So she is being considerate as to when she wont go.
I jumped out R2 to start her and move her on our drive. I tried to restart her later - still would not go.
Plugged Nanocom in - no faults recorded on ECU, also ignition switch shows correct positions. I was playing arround with the gear lever and up popped a gearbox fault - this cleared, but I should mention here that when I bought the car, she had a gear box switch possition fault. I fixed this fault by adjusting the gearbox switch possition. The leds light up correctly, the dash now shows the correct gear selection and I have not had a gearbox possition error for 3 weeks. My question is - does this switch have a separate dedicated circuit for the N/P possition ?
I have just discovered that I can trigger the no start symptoms if I try to start the Discovery in Drive.
The realy strange thing is that putting the lever back into park does no allow the car to start. There is no gearbox fault light it, but the car will restart if I have the ignition switched on in possition II and move gear level over whole range then back into P.
So it looks like I may have a faulty gear possition switch unless the gearcontrol unit has complex logic that locks the car from starting - I may try a further slight adjustment of the selector switch, but does anyone have any idea why once triggered the car wont start until I have run the gearbox over the whole range with the ignition in possition II?

Have reviewed some threads on gearbox switch so am going to clean gbx switch connector - I am guessing that this is a sealed unit so no point in spraying WD40 or contact cleaner onto the switch.
Will also check harness for any wear when underneath the Landi and transfer box switch.

@sierrafery any thoughts on above?
Well I dismantled the gear selector possition indicator connector - looks as clean as a whilstle and the switch looks relatively new - previous owner said it had been replaced. I sprayed the connector contacts with contact cleaner, polished the connections, greased with battery terminal grease and reassembled.
It is a fiddley job but OK once you have removed the connector from the metal support clip.
Also checked the wiring harness - this is encased in plastic ducting and looks fine.
The fault reoccurred, but was cleared by me moving the gear shifter over the whole range with the ignition in possition II. So on the down side I still have not issolated the fault, but the good news is that I seem to have a relatively simple fix for clearing the fault, without jumping out of the car and pulling a relay out of the fuse box.
Plan is to check the gearbox control connectors under the passenger seat, as this section of carpet had been damp when I had the water leak, then monitor over the next week.

ManxDisco said:

@sierrafery any thoughts on above?

Click to expand...

IMO it's a frigging bad contact somewhere.... if it was the XYZ switch itself it should have brought on the M+s warnings and log a specific fault code for that

Thanks guys.
I will keep on hunting. Have also ordered two replacement fuse boxes so I will change these over if the the fault persists.

Change the engine bay fusebox first

@ManxDisco ... have your new fuse boxes arrived yet? Got the engine bay one fitted yet?

Hi Jason
Fuse boxes have arrived but the Landy has not misbehave since!!!. I am planning to inspect the connections to the gear box controls for any corrosion first but wait till the weather calms down.

So you think the problem has fixed itself? Never liked those sort of issues... they have a high tendency of re-occurring when you least expect them.

Hi Jason
You are right of course .
I will put the Landy in the barn and rip out the old fuse box. Thanks for the encouragement. Mike

Hi guys I thought I would let you know that the Disco has behaved faultlessly over the last month.
In summary I had a water ingress problem - fixed by resealing windscreen.
Found a connector which had been saturated with water - dismantled it cleaned the contacts, protected it with electrical contact grease and reassembled. XYZ switch on the auto gearbox was intermittent - I initially got this working by adjusting the switch possition, but I think it may have still been giving spurious signals causing the car not to start. So I replaced it. Top tip if your XYZ switch is intermittent causing the car not to start - turn the ignition switch to possition 2 and go from P to 1 then back again before trying to start. If the gearbox ECU is locked out from a previous switch possition error then this may clear it allowing the car to start, but ultimately a new switch is needed.
Thanks to all on the forum who helped me and encouraged me to fix the root problems.