rover 75 auto-kickdown
 

I have a 2005 rover 75 auto 2.0 v6 petrol. Kickdown works but will not disconnect, very frightning - only way to get it off is to switch off ignition. Can anyone suggest what may be the reason. Gearbox oil changed 2 months ago, garage diagnostics shows no faults.

How do you mean 'will not disconnect' - Take your foot off the throttle? Someone who has an auto will hopefully come along, but as I understand it in the 75 kick down will activate when you 'stomp' (technical term) the accelerator pedal to the floor and then hold that lower gear until you let up on the pedal a bit.


If you are saying that once pedal is to the floor that releasing the accelerator pedal doesn't release the throttle then it's more likely a throttle sensor issue I would have thought? I don't see how else it could be 'frightening' being stuck in a low gear - as long as you have throttle control.

I was thinking the same thing.

If it is related to kickdown and gear changes, perhaps selecting sport/snow mode, the latter likely being more suitable, or even selecting one of the other maximum gear modes on the selector.

I wonder if the scary part is a running away with the power. Perhaps something to do with the inlet system. I have read of blockages somewhere within the V6s that can cause the engine to surge and accelerate unexpectedly.

Do you 'kick down' whilst in 'cruise' to increase speed temporarily? If you do that and then take your foot off the accelerator the additional speed will fall back to the pre-set 'cruise'. That can then be disengaged by braking or the reset button. Just a thought.

Sorry if I didn,t describe problem correctly. In normal mode or in sport mode when sharply pressing pedal to floor the kickdown comes into operation & car drops down to low gear & speeds up rapidly(as it should). It should then slow down & stop reving so highly once you take your foot off the pedal and/or brake. However it does not, it continues to rev high & speeds the car forward uncontrollably. You then end up with the throttle sticking open to its full extent & the only way to stop the car is to switch off the ignition key & brake heavily.With normal(non kickdown) driving the throttle acts as it should & operates without any sign of sticking.

Sounds to me like something is fouling the throttle assy or kickdown cable causing it to jam open.
Another option is in sub zero temps the positive crankcase pressure gases contain moisture which can freeze when they reach the cold throttle assy and freeze the throttle flap.

I would suggest you don't use the car under the conditions you mention without a visit to an expert. Switching the ignition off also cancels out the power steering and the brakes servo assist. Highly disadvantageous.

found the previous post HERE. Whilst it mentions cold weather, I imagine there could still be issues due to blockages.

Hi Walter,

I would start with a detailed inspection of the accelerator cable at its connection to the throttle butterfly. Release it and check the mechanism for free mechanical movement over its whole range then refit and adjust the cable's free play according to the manual.

Simon