Three times now my R53 has cut to idle while driving, and the accelerator pedal became entirely unresponsive. If I put it in neutral and pull over, the car idles perfectly, but the pedal does nothing.

All three times it was while climbing a gentle hill about 3-5 minutes after starting cold, under full throttle in 6th gear. Approximately 50-60 mph.

I discovered the third time, that clicking the key back one click, and then back to run, would instantly solve my problem.

It's been a month or so, and no issues since, but it has me a bit worried.

Am I alone? Any ideas?

 

Give us a little more info. What do you mean by "cut to idle"? Why would you be full throttle in 6th gear going up a hill around 50mph? Why wouldn't you downshift?

Tell us more about what happened each time: experience, symptoms, trial fixes, etc.

 

If restarting the car fix it, it sounds like the throttle body. Many had the issue of loss of power or unresponsive pedal and turning the car off and back on would solve the problem for a bit.

 

There were never any error codes or warning lights, the engine just instantaneously dropped to idle, as if the accelerator pedal had been fully released, but the accelerator was still fully depressed. This was confirmed by pushing the clutch and the RPM drops to idle rpm, even with the accelerator partially depressed and/or cycled. The engine is still running. After pushing the accelerator numerous times, with zero response, I shut the car off and restart, and now it works normally.

As noted above, I can click the ignition back one and again forward to run, and it solved the problem as well, even while still moving.

Maybe it's the throttle body, but I don't know that I'm convinced yet. I'll do more searching on throttle body failure symptoms.

 

UPDATE 7/22/2017:

This random issue is still happening, but I have some corrected and additional information.

I do not need to be under full throttle when it drops to idle. The failure can occur at any throttle setting. Also, in any gear.

This failure seems to occur approximately 3-5 minutes after engine cold start. It has only happened so far when it was sitting out in the sun on a hot sunny day. It has never (yet) failed when coming out of the garage.

In the failure state, the engine idles fine, but the throttle fails to respond. Clicking the key back one and forward again to run will fix the issue immediately.

 

Moving you to the Stock Problems/Issues area.

What year and how many miles?

 

2003 and around 110k miles. Manual transmission.

 

@ ChiggerPepi

i have same problem. Morning start, NO throttle response at all. No matter how i push hard on gas pedal and engine just idle. Have to restart and it will work fine. It happen to me while i stopped at traffic light.

R56 base model (2009) mileage 51,000 miles

Please share your solution if you get it.

 

I use to have this problem with my old R50, turns out my alternator was on its way out. If I could recommend I'd say check that, it seems if it is a momentary drop in voltage the car won't read an error but will throw itself into limp mode.

 

Howdy,
It's the cruise control brake sensor switch on the brake pedal assembly.
The issue is intermittent, and is a fail safe for the fly by wire throttle/cruise control. Just get a new switch.
Jeff

 

Does it do this under only heavy load, or just random times? It sounds like it is going into limp mode (especially if it does this under load).
The fuel filter may be clogged, or the fuel pump is failing and it is not leaving a hard code, so it will start again, with no issues.

 

hi,

I experienced this today, was in bumper to bumper traffic moving slowly and all of a sudden could not accelerate anymore, idle was under 1000 RPM and engine appeared to be on still. I slowed down to a complete stop, put the car in park (6 sp Asin auto), turned it off then back on again put it in drive and was able to continue my way home. I've had complete power loss many years ago typically turning at an intersection where I would lose complete power and have to put the car in park and start it up again and move along. This was completely different losing acceleration but no loss of power.

Any ideas should I be concerned, I don't want to invest too much more into my aging 2005 140k KM Cooper S. It doesn't have the power it used to but it still has plenty of life left in it. Had the valve body done at 100K km in 2012. The transmission seems pretty stable. Engine does have slightly low compression, back in 2016 it had misfired on me waiting in a car wash, dealer diagnosed it slight low compression in some cylinders like 135 psi, some 145 at best.

Thanks again

Anthony

 

Your cruse control brake switch on the brake pedal is faulty, had the exact same issue, replaced the switch, all good.
Jeff

 

I wasn't using cruise control, does that make a difference? is that expensive to change ?

Thanks

 

Wlkrod / Jeff, thanks for this information. As it happens, I have been having issues with cruise control intermittently not able to activate when I attempt to engage, instead the cruise light just blinks twice. This seems to point even more firmly towards your suggested fix. I will change that sensor, but it may be a while before I report back, as this uncommanded idle problem is a bit rare and infrequent, although I did have it happen once last month again.

 

you guys do know that this thread was over two years old before today, right??

Bryan

 

Hi,

Yes it was the only thread I could find related to the problem I had. I went out again to try to test cruise control as I haven't used it in a some time and it worked just fine. I could not reproduce the problem of loss of acceleration I had earlier today. I will monitor it and see how it goes.

Thanks

Anthony

 

A383Wing, yes, fully aware... (obviously as I'm the OP) and yes, my problem still rarely but intermittently exists. Thanks for reminding me it's been three years since I first posted this and it's still doing it? And yes, I never noticed the fix wilkrod posted like two years ago until today... shame on me. I'll work on it tomorrow.

 

Sorry to start an old thread, but I'm having the exact same issue as you had, and this is the only thing I can find on the internet... Did you manage to fix it? I've got not fault codes

Thanks

 

Mine hasn't got cruise control fitted, and it has this problem😳

 

You know, it’s such a rare problem, I keep forgetting about it, until it happens again of course. I click the key back one click and forward, drive home, and forget about it all over again until the next time a month or two later. I need to dig into the brake pedal cruise sensor switch thing. It sounds like the likely culprit.