Faulty cruise control

[Blue_Thunder]

I visited MRC over the weekend to get a remap. First off, thanks to Doug, it's made one hell of a difference!

Whilst down there, the car was treated to it's first Vagcom diagnostics since i've owned it. It came back with two faults, one with the ECT sensor which I knew about, but more interesting was an intermitent fault with the Cruise Control.

I've owned the car for a little over three months and unsuccessfully tried a few times to use the cruise control. A few weeks ago I gave up hope and thought that the stalk might not have ever been connected up.
Thought i'd give it a try on the long motorway journey on the way down on Saturday and miraculously it worked. Used it on and off for a large portion of the journey, then had to slow down to 40 for some road works(with SPECS cameras) and tried to engage the cruise control. Nothing. It then wouldn't work again even when back up to cruising speed.

Has anyone else ever had any similair issues with their cruise control?
Any ideas what could be going wrong?

[david7m]

Did you shift down before pressing resume? I've set cruise in 6th, slowed down and into fourth, then pressed resume. It got all confused and went into limp mode

Dave

[Blue_Thunder]

No, stayed in 6th even when I'd slowed down to 40. As I mentioned, Saturday was the first time in three months I even got it to work.
Does anyone know what actually controls the CC? Is it done within the ECU or does the CC have some kind of control module?

[andrewneaves]

Cruise control works entirely through the engine ECU on the drive by wire B5 there is no other control box. The loom for cruise runs directly from a six pin connector behind the stalk to the white connector on the multi-connector board visible when you access the engine ECU (4 wires connect through to the ECU and one other goes to the fuse board to power the sytem up). Your problem sounds like a poor connection somewhere in the system - the stalk itself, the six pin plug to it, or in the white connector underneath the ECU.
CheeRS,
Andrew

[andrewneaves]

Cruise control works entirely through the engine ECU on the drive by wire B5 there is no other control box. The loom for cruise runs directly from a six pin connector behind the stalk to the white connector on the multi-connector board visible when you access the engine ECU (4 wires connect through to the ECU and one other goes to the fuse board to power the sytem up). Your problem sounds like a poor connection somewhere in the system - the stalk itself, the six pin plug to it, or in the white connector underneath the ECU.
CheeRS,
Andrew