Thread: Cruise Chaos (vs Control)

Not sure if this is related, but....
Have just moved from Qld to WA, including a long haul (with trailer) around the East and South Coasts! I have a MY10 D4 SE 3.0.

When in Brisbane, had some work done (Lower Control Arms and Park Brake). When I got the car back, the cruise control was haywire. It used to be perfect, maintaining correct speed even in moderately hilly country. It now exhibits the following traits:
1. when setting (press Set/+ button), immediately accelerates to 2+km/hr above setpoint. Setpoint displayed on dash is correct according to the speed when the Set button was pressed.
2. when set, slowing using cruise control (- button) has almost no effect. Not until the setpoint is ~10km/hr below actual speed, will the car start to slow. It will never slow down to new setpoint tho.

I took it back to the (reputable) 3rd party LR dealer, who looked at any possibility they could think of, particularly around the items they 'touched'. Could not find anything. Performed reset with diagnostic module, checked all sensors (speed, steering etc) all working perfectly.
I performed a hard reset myself, all to no avail.

So, I now have a non-(poorly) functioning cruise control, which was particularly annoying given we drove ~8000kms immediately after this event!

Any clues???
Could a software update have caused this? They said they updated the software when they did the work in Brisbane....???

Not sure if it's the same issue or not... Sorry to hijack the thread if it's unrelated...

Rob

I too have an issue.

Occasionally looses speed the accelerates, then continues to repeat this action.

Won't do it when Southerns takes it for a spin. I even videoed the instant fuel readout showing the surge occurring.

Bugger.

Brett....

Originally Posted by Ghost-Who-Walks

1. when setting (press Set/+ button), immediately accelerates to 2+km/hr above setpoint. Setpoint displayed on dash is correct according to the speed when the Set button was pressed.
2. when set, slowing using cruise control (- button) has almost no effect. Not until the setpoint is ~10km/hr below actual speed, will the car start to slow. It will never slow down to new setpoint tho.


Could a software update have caused this? They said they updated the software when they did the work in Brisbane....???

Just like mine, although originally reducing the set speed would never result in fuel cut-out resulting in a lot less slowing on down-slopes. At least now if set-speed is lowered enough then fuel is cut.

Mine still has a logic fault whereby if on throttle over-run going down-hill but over set-speed that has been reduced trying to reduce actual speed then the + button is pressed, the + button is treated as being a new activation of CC rather than incrementing by 2 kph. Because the throttle is always opened as a result of CC being set (same symptom as your post), the vehicle accelerates significantly because its still going downhill. Shoddy programming!

In regards to the OP - My 05 D3 has similar issues with the cruise buttons not working on occasion. I decided to have a quick look when it first occurred to see if any faults had been logged with my IID tool - that's when I discovered that the cruise buttons where not working to navigate through the IID menu on the instrument cluster. A bit of internet research and I found this thread, which I believe to be the cause of the issue I'm getting :
DISCO3.CO.UK - View topic - cruise fault
Good news is the bit of wiring harness is fairly cheap to get hold of

Still at a loss. My cruise has not worked at all from purchase, and vehicle history is largely unknown, making diagnosis more difficult.
It has a new cruise switch-pack, which came with a new wiring harness, so we can rule that out.

The rotary coupling / spiral cassette / clock-spring has audible continuity through all plugs, and the socket pins are properly aligned. Some of the signals are weaker, but still audible, don't know why. Possibly cause?

The brake lights work. (Can the brake switch still cause cruise problems if the brake lights work? Guessing not.)

Still no feedback on the "mystery" inverter as possible cause.

It will probably end up being a simple wiring continuity problem, (which is not always simple to locate!) Please keep thoughts coming.

Wasa