OK I picked up my 2008 TDv8 today.

Driving back on the motorway after some time the gearbox seemed to give some hesitation/jerking and soon after the power dropped (limp mode?). Messages on dash included: HDC inactive,

I stopped on the hard shoulder and called a friend who suggested trying to drive using tiptronic (thought it was a gearbox fault). All working fine and covered about 6 miles when power was lost again but this time it cut outq and would not restart.

I must also mention that the trip was reading 17 miles when I joined the motorway and I thought it would go up with motorway driving and services were only approx 12 miles away. Not sure if relevant but recovery guy said it could just be out of diesel.

Recovered back to garage and the following fault codes have been read:
P0501 VEHICLE SPEED SENSOR A RANGE/PERFORMANCE
P0629 FUEL PUMP A CONTROL CIRCUIT HIGH
P0087 FUEL RAIL/SYSTEM PRESSURE - TOO LOW
P0191 FUEL RAIL PRESSURE SENSOR SENSOR RANGE PERFORMANCE

Any ideas?

hmm, smacks of a dodgy battery  Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey

Sounds like you simply ran her out of fuel sir

Obviously your gauge is not too accurate

HDC inactive and vehicle speed sensor could be related as the speed sensor for the speedo is the rear left abs sensor this would also play havoc with your trip recorder, and the abs sensors are used to control speed whilst using HDC , low fuel pressure then as your recovery bloke says it may just be out of fuel , I'd check the battery as well because as soon as the battery starts playing up it can throw up all sorts of weird and wonderful faults one of the main ones being HDC inactive .

Seems a lot of problems for dodgy battery! Also the garage connected a fully juiced up booster pack when reading the codes and trying to start her. £20.00 diesel also added.
I wish your battery analysis was right but I dont think so

I used to get hill descent inactive message on my old TD6 if I left it parked up a few days.
Will check the above suggestions but am fearing the worst.

as Craig says^^^

get some go go juice in it

you have run out of fuel

+1 for no diesel.. I done exactly the same thing the second day I had mine.. The car hadn't been used much before I got it, and One of the sensors in the tank was sticking on full, the gauge told me I had half a tank all the time, next day I took it out,car started shunting, and then boom, car stopped, spec prog off, HDC inactive, wouldn't start ... Confused me when it happened, I'm sitting there thinking it seems like no fuel, but the gauge says I have half a tank.. After a bit of research, I found out there is a valve like a tyre valve under the plastic engine cover, fuel bleeder , my friend spun the car over whilst I held the valve down with a door key, and no fuel came out.. Got a can, filled it, diesel in, then held the valve down whilst turning it over, 15 secs later and fuel started coming through, and car started..

When it's running again, take car back if it's not too far away, and get them to clean the fuel level sensors.. Diesel is oily, and makes the one of both of the sensors stick.. Or, do what I did, brim the car, run it by the trip computer down to about 450 miles, then brim it again.. Hopefully this should unstick the sensor..

OK Day 2 update.
Car is still not starting even with £40,00 diesel. Battery has been charged up also.
High pressure pump is ok. Is it possible I have crap from the bottom of the tank block something like the in tank
filter pick up or worse still destroyed the in tank fuel pump(s)
Has started a couple of times for a split second but cuts out straight away.

As last post.. You need to bleed the system.. Air in a diesel system is bad news.. Ya can't get away with it like you could a petrol..

Pop the hood, take off the plastic engine cover.. As you're looking at the engine from the front, there will be a small black cap, looks like a tyre valve, on the right hand side, near the engine oil cap, at the front of the engine.. You need to hold this valve in, then turn the car over to bleed the system.. When fuel starts coming out of the valve, you're good..

As the car now wants to start, confirms this, but diesel is inherently heavy and oily, and thus relies on a pressurised system to work, ie no air in system..

Last edited by iKushtyy on 30th Jul 2015 10:45pm. Edited 1 time in total

Do you have a picture by any chance?

I can get one now if you'd like, but it's dark, not sure how good the picture would be..

Gimme 15 mins, I'll take one and put it up for ya..

Thank you so much.

OK, I've circled the bleed valve in red, just next to the oil cap.. You don't even have to take the engine cover off, just lift the front up.. Have someone hold the valve down and turn the car over to purge the system of air.. When fuel comes out, let it go, you're good for takeoff ..

Click image to enlarge

Thanks again. I owe you big time if this works. Thanks for the effort at this time of night.