QuestionHi John, my Discovery 2000 cruise control has stopped working. This has been recent; since my last trip a few weeks ago.
At interstate driving speed, when cruise control is applied, it seems to want to engage but does not. It as though there is a slight hesitation then nothing.
My Disco 95 had similar issues, but was much easier for a novice owner/'mechanic' to fiddle with. Is there anything that I can do to see I can fix it without taking it to the dealer? Thanks for your help.
AnswerHi Tristan,
Even though the Disco II has an electric pump, it still relies on vacuum lines. Many times, the problem with CC (Cruise Control) is that either a vacuum line is cracked OR a brake sensor is interfering with the CC electronics.
A LR Testbook can be used to determine the fault codes (if any) that are present as well as the general status of the system.
Pneumatic actuator
The cruise control ECU controls the position of the throttle disc by regulating the amount of vacuum applied by the vacuum pump to the pneumatic actuator. The pneumatic actuator is an air tight bellow coupled to the pneumatic pump via a vacuum pipe. The pump evacuates the air inside the bellow and pipe, which collapses the bellow. This pulls on a cable, which moves the throttle disc to the desired position.
The good sign is that your CC is trying to work but not enough vacuum is being generated to hold the cable in place. Just a theory from where I'm sitting :)
The quick fix would be a trip to the LR dealership. If you know a good mechanic, perhaps he/she could check your vacuum lines.
At this point, it does not sound like a very serious problem (cost wise).
One other cause could be the brake pedal sensor...but this is easy to detect...just check your rear brake lights to see if they are always on.
Best of luck,
JohnMc
