Cruise control disengaging up hills

[muzza_ Junior Member Find all posts View Profile Close muzza_]

Hi there I have an issue with my cruise control disengaging when i'm towing my caravan going up hills.
If its a long climb up a steep hill when the vehicle speed slows from 100 to about 80 km/h the cruise control disengages when the transmission should be kicking down a gear . This only happens when towing, going up the same hill with the car only the cruise stays on and accelerates up the hill.
any thoughts
muzza

[slimf Senior Member Find all posts View Profile Close slimf]

It's normal for cruise to disengage when there is a dramatic change in speed... 20k is a stack of speed reduction. What gear were you in to start with?

[muzza_ Junior Member Find all posts View Profile Close muzza_]

[QUOTE=slimf;451064]It's normal for cruise to disengage when there is a dramatic change in speed... 20k is a stack of speed reduction. What gear were you in to start with?[/QUOTE

was in 4th gear . I would have thought it would kick down transmission and try to return to the set speed when possible.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

[QUOTE=muzza_;451069]

It's normal for cruise to disengage when there is a dramatic change in speed... 20k is a stack of speed reduction. What gear were you in to start with?[/QUOTE

was in 4th gear . I would have thought it would kick down transmission and try to return to the set speed when possible.

On my 150SX cruise control only works in 4th and 5th.

Maybe it disengages cruise when it tries to go to 3rd gear and as the throttle returns it decides you really don't want to be in third and accelerating and the end result is you just roll to a stop.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

That all sounds normal to me, if its going to shift back into third; then 3rd gear and 100km/hr isn't going to work so the cruise turns itself off. Certainly not an issue that needs anything done to rectify, unless you want to trade up to a 200 series with a lot more power, that would fix your issue I reckon

Cheers Andrew

[Justo77 Senior Member Find all posts View Profile Close Justo77]

My 120 does the same when towing the boat, when speed drops to 20km/h below the set speed it disengages.

I do recall looking it up in the owners manual and from memory it does make mention under the cruise control section that it will automatically disengage when the speed drops 20km/h but it has been a while since I looked so I may be mistaken.

[muzza_ Junior Member Find all posts View Profile Close muzza_]

That all sounds normal to me, if its going to shift back into third; then 3rd gear and 100km/hr isn't going to work so the cruise turns itself off. Certainly not an issue that needs anything done to rectify, unless you want to trade up to a 200 series with a lot more power, that would fix your issue I reckon

Cheers Andrew

if it's normal to do that its fine. It took me by surprise as it was going up hill ok then disengages and I've lost all the momentum going up the hill. I'll have to put the foot on the accelerator on the hills.
Andrew 200 series would be nice but i'm happy with the way the Prado performs just a touch slower up some hills.

[discoveraus Member Find all posts View Profile Close discoveraus]

Hello Muzza,

It apears that you have read the owners manual, did you see the section where cruise control should not be used when towing. The vehicle sounds like it is doing its best under an extreme load and operating to save it self from damage. Dont be surprised if something gives up and dies bigtime soon.

You are asking a lot from a 3 litre diesel engine and its transmission.

Read the handbook again and be more sympathetic to the mechanicals under the bonnet.

regards

Ross

[K & M McF Senior Member Find all posts View Profile Close K & M McF]

My 90 series cancels the cruise control when the speed drops 15 km/h. Also agree that it should not be used when towing (unless a very small box trailer).