430 Cup, intermittent TC light + dangerous power cut

[Troyboy]

I spoke to an  ex Elise 220 Cup owner yesterday. He said he had the same problem with his Elise. He said he put WD40 on the switch which he reckons cured the problem. He said the brake switch was sticking. No idea if that is correct just what he said. 

[KIMUTAKU]

Wow believe it or not I just had the same issue today.

Super hot and stuffy weather, I went for spirited driving + hwy and all was fine.  Then I parked the car outside under shades and had lunch for about an hour.  Everything was normal up to this point.  Then as I was leaving going uphill, I came to the first left sweeper, turned my steering wheel and immediately felt something was not right: NO POWER! The car didn‘t stall or anything, just zero throttle response.  Extremely dangerous and nerve wrecking indeed.  Shut it off and started it still no throttle.  Repeated that 3-4 times and finally I got power back.  No CEL light or any tell-tale, dash was normal.

2-3 km later it happened again at a roundabout while I was in the middle of it!  This time power came back on after 2-3 secs… scary sh*t.  Still no CEL or any tell-tale.

After another 30-40km drive home, it did it again as I was at the top of a hill intersection with the steering wheel turned, no power!  After holding up traffic for 2-3 mins I had to roll down the hill 20-30 meters so I could let the traffic go.  After shutting it down and restarting for 4-5 times it finally worked.  I made it home and the TC light came on.

I will be pulling the code ASAP to see what’s up.  Finger crossed…

[KIMUTAKU]

So indeed I got the infamous P0571 brake switch A circuit code… fml…

The TC light actually disappeared before I pulled the codes and it hasn’t come back on since.  Car drives fine at the moment.  So I’m not sure if I should adjust the brake switch (seems to be what most people would do first thing in these situations) or outright replace it and calibrate it properly with the Tech Centre.  Either way, it doesn’t seem like a guarantee fix and the fear of the car losing all power again suddenly on the road is really bugging me.

I don’t understand how this little part can be the source of all sorts of problems with the DPM.  Ridiculous Lotus… *rant*…

[theplanner]

Well if it is any consolation, I experienced exactly the same issues as you….and my car had only done 500km from taking delivery….brand new car….

[Jcx]

Ok i can beat that... 130miles from new on my first Exige - a 350 Sport.  Same switch though... All sorted by Lotus in quick time with minimal fuss.  The 410 has been fine for 13500 miles and three years but i have just ordered a replacement to take on my upcoming roadtrip 'just in case'.

[Dark]

Pumping the brake pedal a few times quickly cleared the issue for me.

If buying a replacement switch I'd recommend getting a genuine one (about £60). There are a few people selling generic replacements for ~£30, I know at least two that didn't work properly.

What fault code reader did you use? Mine didn't show anything even when the TC & Spanner lights were lit.

[Jcx]

I do not know anything about the generic switches, but Elise Parts sell the Vauxhall switch which I believe is/was the same as fitted at Lotus. Elise parts charge approximately £25 plus shipping. It is from them that I ordered my spare switch.

[Dark]

Yes, the generic replacements were from EP and didn't work. Maybe just unlucky? Note they also had the manufacturer logo and part number scratch off so impossible to confirm if it was the correct part.

[Jcx]

Yes mine just arrived from EP and it too has the various numbers scratched off.  I dont understand why that would be done.

[Troyboy]

On 21/09/2022 at 08:29, Dark said:

Pumping the brake pedal a few times quickly cleared the issue for me.

If buying a replacement switch I'd recommend getting a genuine one (about £60). There are a few people selling generic replacements for ~£30, I know at least two that didn't work properly.

What fault code reader did you use? Mine didn't show anything even when the TC & Spanner lights were lit.

At the risk of sounding flippant and I'm not intending to be. I think Lotus have fitted a large number of useless brake switches at the factory judging by the quantity that are failing with not a lot of use. It'll be interesting to see how many Emira owners suffer the same problem. 

[Flaming June]

Add 2 more cars to the list.  Both 2021 Elise.  Sporadic, unexpected throttle cut out whilst driving and on one occasion on a Spanish motorway with no hard shoulder!  Occasional traction control warning light.  Several engine restarts usually required to get the throttle response back.  For however long it lasted (my own record was 7 cut outs in a single afternoon driving Portuguese twisties).  On the advice of Yvo Tuk at Elise Shop we reset the brake sensor and all seemed well again.  The issue didn't resurface for either of us anyway, but it blighted the first week of our driving holiday 😞 

[390ja]

I mentioned a few pages back that fully deactivating traction control cured the power cutting issue for me and made it drivable. Might help if it plays up on you again 👍

[Flaming June]

Thanks.  Not something we thought about doing, tbh, and also not something the dealer who I was in correspondence with mentioned - possibly for obvious reasons.  I'm not sure how we would have coped driving the roads we did with the esp turned off, but it's a good suggestion for those who might not have as many intended miles to cover as we did.  The sensor reset is a 5 mins procedure though and it worked for both cars and c.1000 more miles each.  I'll be heading to my main dealer soon for a new sensor. 

[Jcx]

What did it take to reset the sensor? Push in and pull out?

[Flaming June]

Yeah, pretty much but the other way around.  Extend the plunger as far as it will go (but don't actually pull it out of the switch housing as I did - doh!) then push it all the way in and then - carefully - extend it out slowly one notch at a time.  There's an audible 'click' per notch and 6 notches seems to be the adjustment for the Elise ie to work the brake lights as they should.  

[390ja]

7 hours ago, Flaming June said:

Thanks.  Not something we thought about doing, tbh, and also not something the dealer who I was in correspondence with mentioned - possibly for obvious reasons.  I'm not sure how we would have coped driving the roads we did with the esp turned off, but it's a good suggestion for those who might not have as many intended miles to cover as we did.  The sensor reset is a 5 mins procedure though and it worked for both cars and c.1000 more miles each.  I'll be heading to my main dealer soon for a new sensor. 

I tried it as a last ditch effort to just limp to the dealer for repair. It was dangerous to drive with the intermittent power cuts. It drove perfectly with the traction off, weather was glorious and only 50 miles so no worries about getting in a mess.

[Troyboy]

The 1st time it happened to me I switched the engine off counted to 10 and switched it back on. TC light went out and I switched the race button on. It never came back and hasn't done so while in race mode.

[390ja]

Same here with switching on and off again, but mine also coincided with a puncture the next day, so I assumed that was what triggered the TC warning. After fixing the puncture I had a couple more episodes, each time becoming more problematic, until it became dangerous to drive. 

[KIMUTAKU]

Dang wasn’t expecting so many newer cars to have this power cut issue!

The TC off mode only works if your TC light hasn’t come on.  Once the TC comes on you can’t switch to any mode at all.

I didn’t install a new switch and simply pulled the existing one out and adjusted it to 6 clicks (was at 5 clicks).  So far so good… 

[Flaming June]

Update - Bell & Colvill replaced my brake switch under warranty (with a part from stock) and in doing so found a fault with the factory fitted switch - P0571 Brake Switch A Circuit.  I'm still investigating, or rather I hope Lotus are as I have reported the issue, the specific cause of the fault (online research suggests it's the CC circuit) and why it led to the throttle cutting out without warning.

The OBD reader we used on our trip didn't detect any code - even immediately after a power loss episode - so if you've suffered this or a similar problem then probably a good idea to get your car checked over at its next workshop visit or simply fit a new switch. 

[Troyboy]

I've been using my car weekly and with regular use the problem never came back. After 2 and a half weeks sat in my garage I pulled the car out to my drive and the light came on. No issues with power. I did 40 miles with the light on. I switched the engine off and back on 2 minutes later and the light cleared itself and never came back on. Sticky switch that needs lubrication on my car. I hope. 

[ashtizadeh]

Hey guys, faced the same issue here. 
Was driving along one day and made a fast-ish long right turn and suddenly lost all throttle response. Very dangerous mid-turn as you can imagine. 
At first I suspected it was a throttle valve connection issue since it’s drive-by-wire so I cleaned out the throttle and cleaned out the throttle pins with throttle pin cleaner (I discovered that that’s a thing on that day). Did the whole throttle relearning dance with the key in the on position with the engine switched off - slow in all the way, hold for 3 seconds, slow out (x3).

Sadly that didn’t solve the issue cause it had nothing to do with the issue. I’d get a random CEL and/or service light (the spanner) and they’d go away after a couple of minutes, the suddenly the “traction off” light comes on followed by loss of throttle soon after. 
 

Bottom line is it was a faulty brake position sensor. Apparently these cars are very reliant on what this sensor tells them and if the sensor starts speaking gibberish, the car simply won’t have any of it and lock you out of fun times. 
 

Had the brake position sensor replaced at the dealer (stupidly expensive part for something that has “GM” written on it) and the car’s been running flawlessly ever since. Even took it to the track a couple of times and it was still good after. 
 

Anyway hope this helps cause I was stumped at the time.