Greetings from the North Devon coast.
I would be grateful for any hints, advice or suggestions. I am away from home (Plymouth) at the moment and have no tools here with me: I can work on the car this weekend.A couple of weeks ago I jumped into the car (it is a D9 btw), threw the key into the ignition and turned it to find that the engine security light (a key in a box symbol) came on and the car would not start. It cranked over fine, but did not start. I was aware that I hadn't allowed any time for pre-heating, though I don't think lack of pre-heating was the issue. I removed the key, took a deep breath, reinserted it, turned ignition on, paused, and the car started normally, with no sign of the warning light.
About a week ago the car refused to start first turn of the key. There was no warning light. It started normally on the second turn.
The, on Monday it was a cold, cold morning. -3.5 according to the in-car display at 0730. Turned over normally, no warning lights but no ignition. I tried maybe eight or nine times. I had to leave it then. Today Wednesday at 1200; a warmish spring day and the car started first turn of the key.
I should add that the in-tank life pump makes the right sort of noises when the ignition is turned on.
My chum with the code reader found a key code fault, and believes this is why it would not start on Monday. No error codes related to glow plugs or relay. I am doubtful that the key code is related to non-starting on Monday as there was no dashboard warning light illuminated. I read a thread here about the code pick-up on the key barrel taking a little time to read the key, and wonder if that might have been the case on the first failure to start, a couple of weeks ago.
Question 1: I wonder, does the system actually monitor the health of the glow plug / relay? Perhaps there never would be fault codes for these items!
Question 2: Should I change the key battery in any case? I guess it is the original battery.
My diagnostic plan is:
1) Check power is reaching the glow plugs.
2) Check resistance of each individual glow plug (0.5 ohm I read on another post is normal)
3) ... er, that's it.
Any suggestions, hints and tips would be hugely welcome.
Regards
Springnuts
; it is +5. There is however no noise from the in tank pump 
... .
. I now get only a very faint humming from somewhere like a fan starting up - it happens whether or not the pump is connected, so is clearly not the pump! Pumps are not in stock anywhere locally, but ebay for £80 all in (PEUGEOT 206 406 2.0Hdi Diesel Fuel Pump FP5315) seems a bargain; I can get a secondhand one down the road for £40 which doesn't sound worth it. The securing ring looks hard to shift: access v poor - I will check I can get it shifted before ordering the part.
- am just about to start on a template.
Things that may go wrong .... wrong pump arrives; securing ring shatters; seal is perished; pump is the right pump but just 1mm bigger/smaller then the supposedly identical one it is replacing; pump fits but doesn't work; tank level sender gets knocked off ... 
)
