I too had intermittent cranking, sometimes had to press start button a few times to crank.
Eventually it stopped cranking completely, new starter solved the issue.

When it did start intermittently just after engine fired into life I got an slight electrical burning smell through the heating vents no smoke just a whiff of something electrical burning.
Guess this was the solenoid contacts on there last legs.

When I took the original starter off, checking it with some jumper cables revealed a dead / jammed solenoid.

Starter relay is part of the starter motor it is normally the live terminal inside the relay that gets burnt. This leads to the clicking as the ignition key activates the solenoid but the power connection is not made so starter motor does not activate. At first it will normally work after several attempts and may work for a short period before failing again. Using a booster pack increases the voltage which helps overcome the burnt terminal and gives enough oomph to jump over and activate the starter. Only long term solution is to replace the starter 2012 tdv8 Westminster arrived Jan 19 gone Dec 23

200 TDi discovery bobtail gone
RR classic v8 bobtail gone
300 tdi Discovery 3 dr gone

GraemeS wrote:

A known issue is the trigger wire from the starter relay to the starter solenoid not being able to carry enough current to cause the solenoid to be operated with sufficient force to hold less than perfect contacts closed. The wire is over 6m long, half of which is 4mm2 and the other half 2.5mm2. People have found that installing a replacement wire between the relay and solenoid overcomes the starter malfunction. A new starter will also overcome the problem while the contacts are in good condition.

What Graeme said.

Long term solution is to keep the electrics happy in the path, from JBB > BCU/JBC > JBE. I think the culprit might be the resistance developed over time causing supply drop. This is the case for me. Starter solenoid could be a side effect due to poor contact over time.

Now with all the electrical clean, my car feels like it starts differently ..assured. ..even with low battery voltage.

Note: I may still have a drain someplace that i am chasing, I going from corner to corner stripping modules etc. I have also cleaned all the blade /mega fuses.

BTW JBC is the BCU 2010~12 cars, where car keeps master CCF etc ..keep is happy with clean juice  SOLD | Tuned MY 2011.5 Range Rover Autobiography 4.4 TDV8 Orkney Grey | e-diff | ACC

New Toy: Unimog U1550L/37
New : G350D

GraemeS wrote:

A known issue is the trigger wire from the starter relay to the starter solenoid not being able to carry enough current to cause the solenoid to be operated with sufficient force to hold less than perfect contacts closed. The wire is over 6m long, half of which is 4mm2 and the other half 2.5mm2. People have found that installing a replacement wire between the relay and solenoid overcomes the starter malfunction. A new starter will also overcome the problem while the contacts are in good condition.

Finally made my way into the engine/starter circuit, removed and cleaned trigger wire form starter relay to starter seem ok. Can do with thicker wire.

Following "interesting observation made"

Voltage drop to the starter relay coil from ECM it self .5v~.75v. This will still work when the battery is charged, but a weaker battery will result in this relay staying open and "no crank". Appreciate ideas to nail down the voltage drop/resistance pls

 SOLD | Tuned MY 2011.5 Range Rover Autobiography 4.4 TDV8 Orkney Grey | e-diff | ACC

New Toy: Unimog U1550L/37
New : G350D

Stop swapping starters folks, I think the issue is with the starter relay which is badly pitted and burnt over time. What
V8 Bob said.

Click image to enlarge