Scary Experience - Renault Z.E. Forum
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post #1 of 30 (permalink) Old 12-25-2014, 04:49 AM Thread Starter
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Scary Experience

Well, after a year of motoring with my replacement Fluence she did the dirty on me. What happened bears an uncanny similarity to some of the bad behaviour of my white car - which I returned before it killed me. As we have had several new members who probably haven't read my earlier posts I will briefly recap.

Car No.1, the white car, bought before prices came crashing down, started off (300 miles on the clock) in its first week of ownership by refusing to brake when I needed it to at a busy roundabout. It just ploughed on regardless. Several weeks later and it was returned to me and the very next day as I left home I got the "brake failure" message and parked it up. At the second attempt at repair more parts were replaced and I was back motoring again.

The next braking episode was while I negotiated a busy village street and needed to slow to avoid a dustcart. Foot on the brake and electric motor failure" appeared in front of me and the car ACCELERATED towards the obstacle! Several weeks later and I was told the car was ready for collection. On enquiring what had been done I was informed that they had not found the cause. i was unprepared to accept an unrepaired car and rejected it. Much discussion by all concerned and the supplying dealer provided my current car as a replacement.

Now to Car No.2, blue. This apparently had impeccable history over 2700 miles of usage by Renault management. The dealer felt this was the safest bet! Apart from not going as far to a charge as the earlier car (some 10% down, I reckon) it has behaved itself - until last Sunday. Gently negotiating a tricky bit of road with blind bends at no more than 25mph I needed to avoid an oncoming car so I eased off the throttle and gently applied the brake. Once again I felt a shove in my back as the car lurched forward, ACCELERATING. I stamped on the brake and the car did respond and I stopped in time.

I have to ask how can applying the brake make a car speed up? Everything's fly by wire so it's not going to be a mechanical fault. So it's either electronics or software. Either way I am terrified that the car will do something similar at speed and there will be an almighty crash.

My plans for Christmas have been put on hold as my intention of bringing my 90 year old aunt out for the day have been scrapped. I shall spend Christmas pondering what my next step is. Is it a matter for a towtruck to the nearest specialist again? Or a pleasant chat with the oh so helpful folk at Customer Services who have no answers? Or straight to the supplying dealer who Renault last time would not allow the car to go back to to be sorted - their excuse, "There's a nearer specialist, they've got to learn how to sort these cars", to paraphrase.
Maybe an identical letter to all three and see what results.

Of course, I could continue to use the car until the next event, then park it up if I can stop it and walk off. Or drive it into the nearest river? I have given Renault's EV's two years of my time and considering the catalogue of events (more that I've outlined here) I reckon I've been remarkably patient. But enough is enough. I'm 75 and rather fancy reaching at least 76, Renault.

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post #2 of 30 (permalink) Old 12-25-2014, 06:25 AM
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RE: Scary Experience

I've never had anything approaching an unusual occurrence like this - although I did hear about someone with a Vauxhall (can't remember the model) who found he had braking anomalies displayed - not regularly - but on certain occasions during the winter months. The car always checked out fine, but the log did store the failure event.

Speculation ranged from RF interference (MoD, CAA Radome, microwave link etc) as the error, which could never be recreated on demand, appeared to show itself near the summit of a hill that could have glowed in the dark with the amount of technology sired upon it.

My blue one has been flawless, but I'm aware of these hot-spots and have never had any need to go past them. I think your issue is one of external interference acting to the detriment of the Fluence. But what?

We all the remember the stories of not using mobiles on planes or near hospital ICU departments. Some had flawed reasoning, but there remains a modicum of doubt.

The recent wayward Glasgow bin lorry is a case in point - was it driver error that caused it career up Queen Street and smash into a hotel killing pedestrians on the way? There's been conjecture that the driver was slumped over the wheel, whilst others say he was frantically trying to manoeuvre it through the first junction.

Cold comfort - but I'd watch the results of the finding with interest.

Oh - and Merry Xmas to all!
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post #3 of 30 (permalink) Old 12-25-2014, 09:04 AM
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RE: Scary Experience

Is it actually accelerating or is it just a drop in braking that gives the impression of acceleration?

The reason I ask is that what you describe sounds very very similar to the Prius braking anomaly that caused all the recalls in early 2010. That seemed to happen on wet, damp roads or wet grate covers etc. It was hard but not impossible to replicate for the dealers and eventually it turned out to be the transition between regen and friction brakes in a situation when the ABS kicks in. If the car was on regen only braking (as the original programming allowed regen only braking in certain circumstances above 7 mph) and the ABS kicked in because of a slippery road etc, there was a hesitation/gap/surge between regen being switched off and the friction brakes having to suddenly 'wake up' or engage. This transition has been measured in the milliseconds but is still noticed by the occupant and feels like a surge. Engineers on the Priuschat forum showed charts with accelerometers etc that there is no acceleration, despite it feeling very much like that; just a flat spot in deceleration.

Since all that trouble the braking has been reprogrammed to allow an element of friction braking and regen at all times (other than below 7 mph where it is friction only), so that if there is a slippery moment the friction brakes are there to take over much quicker. The down side of this is that the Prius now uses it's brake pads at the same rate as a traditional car (almost). It has been a significant balancing act and has resulted in a number of software updates to make it much more acceptable/smoother.

I wonder if something similar is happening with the Fluence? I wonder if you're being gentle on braking and just using regen that when the ABS kicks in (esp now in winter with wet roads) you experience the surge as reported above. When lead footed dealers mechanic stomps on the brakes, they can't reproduce it as the car is immediately using friction brakes and regen?

I could be on the wrong track but it does seem very similar to the Prius issues. Obviously if this is the case it could be totally new to Renault, whereas Toyota have had 5 years to investigate.

Just a thought?

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post #4 of 30 (permalink) Old 12-25-2014, 02:43 PM Thread Starter
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RE: Scary Experience

Thanks for the responses so far. I do hope, Busby, that you are wrong or my experience will become ever more commonplace as cars get more electronic. My long ecperience of electronics and computers does not give me the faith to trust them in the way that earlier technology performed. Their root problem is that failures are often catastrophic and, with increasing complexity, unpredicatble. You try getting any bit of electronic kit repaired! It's cheaper and easier to chuck it for another. Is this what cars are coming to? Incidentally I have a giant MOD base in my village and antennae on top of the hill up the road. But my failures so far have all been away from home.
Grumpie cabbie, I get your point too but all instances have been at comparatively low speed on good roads in good weather. What I noticed this time was a shove in the back as the car's torque pushed the car forward violently. I note that Leaf owners can suffer from mis-match between regeneration and braking that causes them to jolt to a stop, but that's another story.

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post #5 of 30 (permalink) Old 12-25-2014, 03:01 PM
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RE: Scary Experience

The one thing that makes me wonder if it's a software and/or programming issue similar to the Prius problems is that, and I say this with the greatest respect, only one driver has had a problem with two cars.

Is that really bad luck or coincidence?

Or does he drive carefully and slowly, using the regen to slow the car? All very worthy but is this what's catching the car out?

The Prius has had this regen/friction issue, as has the Leaf and as has the Volt (US Ampera). It would appear logical that Renault would too, especially as the Leaf is similar in some ways.

And I just don't get why one owner has had the issue on two cars unless the problem is there on all cars and it's that his driving style is picking it up more often? I have had the Prius braking anomaly occur about 3 times (before the recall) and it is scary and does feel like you've been rear ended, but the graphs and detailed explanations pointed out that it is just a slowing of deceleration. Difficult to describe without the graph, but imagine you're slowing from 30 mph over 2 seconds as follows; 30, 29, 27, 24, 22, 21, 19, 19, 19, 19, 19, 19, 17, 15, 12, 9 etc. That constant 19 mph would feel like a surge.

Or it might be nothing like this at all. But sounds logical and very feasible to me - though I would say that
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post #6 of 30 (permalink) Old 12-25-2014, 06:59 PM
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RE: Scary Experience

Hi Paul,

Merry Xmas. Yep, I've had brake failure twice in the Fluence.

Both times were after driving through pools of standing water and getting the red brake warning sign on the dash. If you ignore the warning and carry on (knowing that the sensors are flooded with the drenching) your brakes are fine for about 20 mins. But then watch out - you suddenly aint got hardly any brakes at all. I've not had the feeling of acceleration you describe - just no brakes.

Once everything has dried out all is back to normal - the moral is take the red brake warning light very seriously - I have about 20 mins grace after it comes on, and both failures have been sub 7 mph. Previous posts seem on the money there. But scary - yes, you just keep rolling forward.... I reached for the handbrake on both occasions.

Never mind- still love the Fluence (hec, I must do...) and now on 19,000 miles.

All best to you all for 2015, keep the faith,

Chris (number 6, or was I 5? )
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post #7 of 30 (permalink) Old 12-26-2014, 05:50 AM
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RE: Scary Experience

The interference issue cannot be discounted as a valid potential cause - as you say, our vehicles have become things that no mechanic (without a laptop) can ever hope to diagnose, and even then such diagnoses may be invalid or show nothing.

The MoD site I referred to did not become a problem simply by being nearby - that would be too easy. The issue depended on a number of factors coming together at the same instance to create the RF required to cause a particular effect... Like getting three bells on a one-arm bandit.

We've recently had stories of RF key blocking and cloning - not an issue for the Fluence as a physical key blade is still required before any forward motion can be engaged, but since insurers already accept this as a non-force entry to a vehicle, ignoring the effects of other external interference that can cause the effects described may well be unlikely, but certainly not impossible!
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post #8 of 30 (permalink) Old 12-26-2014, 06:18 AM
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RE: Scary Experience

I would always go the newspaper/magazine route for the simple reason that Renault won't care about individual complainants turning up at dealerships but they will care about a PR trainwreck in the national press.

Give Renault a chance to respond but then take your story and backstory to someone like Haymarket (What Car? et al).

Having said that I would be inclined to wonder if GC might have put his finger on the problem here, in that a total lack of regen when lifting your foot from the throttle and gently applying the foot brake - my car's done it on numerous occasions, leading me to start a thread here wondering if the regen levels were dynamic - can feel like the car is getting faster, whereas it is in fact merely not slowing as quickly as your brain is expecting.

You can see how your senses might get confused, particularly in an instance when you've had the same sort of vehicle misbehave previously. And I can totally see how you no longer trust it.
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post #9 of 30 (permalink) Old 12-26-2014, 07:54 AM
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RE: Scary Experience

Quote:
Originally Posted by Eep
Having said that I would be inclined to wonder if GC might have put his finger on the problem here, in that a total lack of regen when lifting your foot from the throttle and gently applying the foot brake - my car's done it on numerous occasions, leading me to start a thread here wondering if the regen levels were dynamic - can feel like the car is getting faster, whereas it is in fact merely not slowing as quickly as your brain is expecting.
You've had experience with BEVs and/or hybrids I believe.

The issue seems to be regen only braking and how it is completely incompatible with ABS as the pulsing on,off,on,off can cause damage to the regen system/inverters etc. The car has to 'switch' to friction braking in ABS situations.

If a driver is easy on the friction brakes by gently slowing 90% of the time with just the regen, then the friction brakes are cold, possibly rusty or mildly corroded or even just wet. When the car suddenly needs them in an ABS situation, they're just not there to the degree they should be or would have been if there was no regen or if the two systems (regen & friction) had been blended more.

Renault haven't had a hybrid or much experience with regen brakes and will have to be learning from the beginning. This sort of issue, assuming it is the above, has been known about since the early days of hybrids 13 years ago.
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post #10 of 30 (permalink) Old 01-02-2015, 03:41 PM
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RE: Scary Experience

I have to agree that this could well be an EMC issue if you have had the same experience in a similar location before.

It is not unheard of. In the early days of electronic accelerator pedals there were several such incidents. We're seeing a change of technology here so (at the risk of sounding overly casual about such a terrifying experience) it will probably happen from time to time.

I think you should describe the experience in detail and post it to Renault in France, directly. You could email a copy to UK Renault if you like but they are concessionaires and cannot really influence the technology. Your experiences could be very important and if it goes through to the right person then it should get an appropriate, active response.

If you have any problems getting through to someone sufficiently high up in Renault that is responsible for EMC issues, then PM me and I could see if I can find a way to forward your letter on appropriately if you like (my company has representatives who sit along side Renault representatives on EMC committees).

It may not be an EMC issue, of course, but it sounds plausible and it could be a dangerous issue that needs to be bottomed out.
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