fault codes and limp home mode

[petesh]

I have a 2008 RRS with 91000 on clock. Recently it has started raising random faults and going into limp home mode. These errors include - HDC failure; transmission failure not all gears available; engine fault; park brake fault. I do mostly long distance work on bitumen with the car and can go several hundred km without a problem or break down 5 times in 6km.. yesterday it broke down 5 times in 4 km after driving 600km. It then did a further 150km with no problem.
I took it to the dealer a couple of weeks ago and was told it was the battery so bought new battery. then next trip same problem. back to dealer and told battery terminal was loose. next trip replaced all tyres with new top of range Michelins. next trip (900km) no problems. next trip after 600k broke down 5 times took to dealer and told that there is no codes in the system showing any problem. Have left with dealer and told them to fix it. They have told me they cannot find a problem.
I drive highways only and pull a 3000km caravan and have serious concerns about it happening on the highway with the van on.
Any suggestions?

[Graeme]

Look for loose connections at an earth stud where the nut is not tight. Near the brake master cylinder there is a significant one.

[TDV6]

I've had my battery replaced three times, each time I got those cascading list of errors, so now know what to expect with low power etc.

I carry a test meter to check voltages etc. You say they reported a loose terminal clamp that needed tightening so has the earth strap connection to the body been checked as well?

Intermittent faults are a PITA as when it working there's no indication whats wrong.

Sorry to hear of your problems.

Ryall

[petesh]

I took it to the dealer and told him not to give it back till it was fixed as it is still under extended warranty - just. I trust they are smart enough to check all connections given they said it was a voltage issue.
They gave me a new Evoque to drive around in and I have now been four days whilst they try to locate the problem. they said there was no record of fault on the computer chip. They called me last night and said that they had found a fault in the high pressure fuel pump and that a senior mechanic there said he had heard of this causing these cascading faults, so they have ordered a new high pressure pump and will install it during the week.
I tow a caravan (3tonne) so cannot afford to have it happen in a bad area with the van on so they need to fix it. Hopefully We will see that they are right and the problem is fixed. I note on some of the old threads that D2s used to have a limp home problem caused by fuel issues, so maybe this is the problem. Will let you know in due course.

[jonesy63]

A faulty brake switch can also cause those errors.

[lt8x7]

A faulty high pressure fuel pump can cause these problems.

I had the same symptoms and replacing the pump (under extended warranty) fixed the problem.