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Random power cuts and kicked out of Sport / Race, brake pedal switch?? - Ride/Handling/Suspension/Brakes/Wheels/Tyres - The Lotus Forums - Lotus Community Partner #ForTheOwners Jump to content


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Random power cuts and kicked out of Sport / Race, brake pedal switch??


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Hi folks,

Hopefully you can shed some more light on the problem I'm experiencing. Over the last month (and shortly after an ECU reset disconnecting the battery, but I guess it was a mere coincidence) the following is happening to my Exige 410:

-Most of the time right after breaking or after a few seconds of braking and pressing quickly and gently the throttle pedal (almost fully) the car simply:

1) Cuts power off for 1-3 seconds, similar to when you hit the rev limiter

2) Kicks me out of sport/race mode

3) After those 1-3 seconds everything goes back to normal, no dash lights and no OBD errors are logged 

It is not happening all the time, it is quite random, but it at least happens 1 or 2 times every time I use the car, after reading a lot in the forum apparently there could be 2 culprits, the infamous brake pedal switch or the steering wheel sensor, I've noticed that my brake pedal is extremely sensitive, when I have the cruise control on simply by putting my foot on the pedal (maybe moving it 1-2 mm) the cruise control gets disconnected

Next steps:

-I've ordered silicone grease to put it on the pedal switch plunge

-Moving the plunge one click in, in order to make it less sensitive??

-Replace the switch itself?

-Take it to the dealer ??? I would like to avoid this one as the closer dealer is 400 km away, and on top of that no error is being logged in the ECU

 

Any hits or help would be much appreciated 

Regards

Edited by cuprapw
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Upgrade today to remove Google ads and support TLF.

Ok today I got the dreaded TCS light plus a wrench icon in the dash

later, the car even went into some sort of limp mode (P2104 Throttle actuator control system - Forced idle)

I also read the codes:

P1106 and the more specific P0571 Cruise control/brake switch A circuit 

So 99% a faulty pedal switch brake sensor, I've ordered a new one from elise-parts

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More to the story

I reset yesterday the switch as per the service notes instructions, and so far so good (20 miles with hard braking and accelerations, no heel and toe tho).

With 5 "clicks" the brake pedal is not that sensible to kick you out of cruise mode simply by putting the foot on the pedal

Another interesting data-point is that it also started to misbehave as I stared to use more and more heel and toe....to me that is insane in a car like a Lotus Exige 

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4 minutes ago, cuprapw said:

With 5 "clicks" the brake pedal is not that sensible to kick you out of cruise mode simply by putting the foot on the pedal

I'm sure that pretty much every car is meant to cancel cruise control when you depress the brake pedal. It's one of the ways to turn it off. 

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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2 minutes ago, Bibs said:

I'm sure that pretty much every car is meant to cancel cruise control when you depress the brake pedal. It's one of the ways to turn it off. 

Yes, definitely, but not just literally when you put your foot on the brake and move it 1 mm, at least that is not the behavior in my other car with CC, you need a bit more than 1 mm for it to kick you out of CC

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  • 2 months later...

Its definately the brake pedal switch. Mine did the same thing in first 1000kms of ownership. I also had a problem with the earth cable coming lose on body causing electrical faults. A new brame switch and reconnection if earth cable and trouble free driving since

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  • 2 weeks later...
  • 2 months later...

My 390FE does this too less than 1k km's on it  My car does not have cruise control but it does have the kt powersteering on it....

with over half a tank of gas it cut revs on me and wouldn't allow me to rev higher than where it cut.

With a little over 1/4 tank and someone else driving it did this kick out of sport/race mode multiple times.

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I can tell you that my Exige kicks out of SPORT to TOUR in case gas and brake pedal are presses simultaneously. Haven't tested it in RACE mode. Based on that, I would say occasionally faulty brake switch?

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I seem to recall that's programmed into the ECU for legislation reasons. 

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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5 hours ago, DangerousDave said:

What so you can't heel toe?

Lowest common denominator. Can't remember if it was our govt or the EU that said if both pedals are pressed at once to cut power. It's for those will less cognitive power who press the brake and throttle fully rather than clutch and brake, to stop them slamming into a wall. 
 

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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You categorically can heel and toe in any Exige. Some are easier than others, and most require some learning and that you are VERY good at heel and toe (ie, can adapt to variances in timing required to other cars).  I've driven several Exiges where the owner says it's impossible to heel and toe in it, when actually you just need to learn the slightly weird timing required to do so, and it is in fact possible.  They've all been possible, and in all modes.

What you cannot do is left foot brake and accelerate at the same time as this will cut the throttle.  I assume there is a sensor on the clutch that allows the ECU to differentiate this.

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Wow really? Need to test this, thanks 🙂 I was driving it straight (as said, testing brakes) and it threw sport mode to tour. When I think what it was… Left foot was off the clutch, steering wheel was straight. But pressure to the brakes was way higher than what would be needed for the heel and toe. Could be that it takes into account brake pressure and steering wheel position. I can’t imagine how clutch sensor would recognize heel and toe situation. Do you mean some kind of a sensor that recognizes that the foot is on a clutch pedal ready to kick in?

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  • Gold FFM

The car can't measure brake pressure. It knows the brake is being depressed, and there are two stages for this. But both of these stages are operated well in advance of 'heavy' braking. The AIM dash data logging allows you to see both brake switch traces. I think one is called Brk Switch Light, and the other other is Brk Switch ECU (Or something like that)

With regards to the clutch pedal, I believe this is just a single stage switch which operates when the clutch is fully depressed. 

As for my personal experience, no matter what I've done on the road or track I've never had the car take itself out of Race mode.  

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My car had similar issues with around 1000km done.  Power cut out (out of blue) when on highway, kicks out of full traction off and into tour mode with TCFAULT displayed but car still drivable.  Fault was P0571 for the brake switch and apparently with my car, the sensor was faulty and thinks brakes are on hence the errors (e.g. it thinks Im left foot braking whilst on the accelerator).  Time will tell if this has completely fixed my issue.

On the topic of heel and toe, can definitely H&T in every mode (tour, sport and race) I have had no issues.  Like GFWilliams was saying, just need to learn to modulate your foot pressure on the pedal.  However, you do need to be more precise otherwise it could throw off the balance of your car due to the jerky changes especially if you H&T late into a corner. 

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16 hours ago, theplanner said:

My car had similar issues with around 1000km done.  Power cut out (out of blue) when on highway, kicks out of full traction off and into tour mode with TCFAULT displayed but car still drivable.  Fault was P0571 for the brake switch and apparently with my car, the sensor was faulty and thinks brakes are on hence the errors (e.g. it thinks Im left foot braking whilst on the accelerator).  Time will tell if this has completely fixed my issue.

On the topic of heel and toe, can definitely H&T in every mode (tour, sport and race) I have had no issues.  Like GFWilliams was saying, just need to learn to modulate your foot pressure on the pedal.  However, you do need to be more precise otherwise it could throw off the balance of your car due to the jerky changes especially if you H&T late into a corner. 

Sounds like a recipe for a wreck. Time to go full retard and bite the bosch m5 abs with motec bug.

Even without braking on the straight i was at around 4k and wot when car at more than half tank rev hung on me and i couldn't get any higher, did a cool down lap shut car off and it was ok after restart but just weird...

I guess this wasn't a kick me out of sport/race into tour tho

 

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Not sure that would fix the issue in my case as a sensor was faulty therefore sending signal to ecu to play it safe. Beats me tho that this is a known fault, yet it has not been fully rectified years ago. How so many brand new cars can hv this same issue keep recurring? 

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