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Traction/ stability control oversensitive

4855 Views 40 Replies 15 Participants Last post by  smokie
Recently I've noticed my Ampera is jabbing the nearside brakes on and off during left hand cornering. This is occuring even at quite slow cornering speeds and far from helping the handling it is actually making the car feel quite unstable with bucking bronco like handling.
I first noticed it a couple of months ago when I enabled the sound in My Green Volt app for when the mechanical brakes are applied. It was playing the tune nearly every time I went round a left hand bend and then I noticed the traction control light was coming on at the same time. This can't be doing the tyre/ brake life or economy much good! Has anybody else noticed this? Is it just a badly tuned system and normal for the Ampera/ Volt or is it a problem with my particular car?
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I've not noticed this myself, unless there is actually bad traction (fast cornering or cornering over a grid/pothole)
Not noticed it but will certainly be scaring a few people on roundabouts over the next couple of days to make sure it's all okay.
Mine does this but only on one particular corner:confused: Its a 90 degree right that is slightly up hill and heavily cambered. The TC light also flashes and I have no power for a second while it sorts itself out. My Dads Ampera on the same corner is OK. As I have never been able to reproduce it on any other corner in my 23000 miles I have never complained as I know the dealer would not be able find a fault:cool:
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@PRO-AMPERA it's interesting that yours and your dads Ampera behave differently on the same bend.
I don't remember mine behaving like this when it was 'new' last October apart from when the inside front wheel lifts when pulling out of RH junctions like most other modern cars.
I think I will double check my tyre pressures with a different gauge as the onboard pressures are reading 37 -39 psi v 38 all round on the pump. I might even swap the wheels & tyres around left to right and back to front when I get time to see if that makes any difference. I wonder if there is a way to reset the system?
Never had anything like that, but will try pushing left handers with accel to check. (I drive like a grandad, or slower, not sure I have ever got anywhere near traction control, excepting perhaps a couple of deep accels to test the car does deliver on its 150hp!)

Noting the delta between two Amperas .... what model years do you have? Clue;- MY2012 no rear armrest, MY2013 with rear armrest.
Have only had that once when throwing the car into a left hander too fast.... Could feel it struggling not to continue in a straight line.
Otherwise, I drive too slow for that to happen ;)
I found it quite a bit on one particularly rough surfaced corner, then more recently on other corners when the weather was really hot. Never had it since the rough road was resurfaced and the weather hasn't yet been hot enough again.
I first noticed it a couple of months ago when I enabled the sound in My Green Volt app for when the mechanical brakes are applied.
Wish I had known about this sound earlier, I hope it is interesting!.........Then again maybe not, I don't want to be tempted to force it.
There's always someone that has had the same problem! Ditto!
Mine also cuts in a rear brake through the stability control on just one corner on the way home from work, it's a off camber weirdly shaped lefthander. If I tip it in at 42 it will bong the brakes on mygreenvolt and the dash light will flash. If I do 40, it usually does not. Turn the stabilitrak and traction off though and it is fine.
errr.... is MGV the common feature here?

A cheapo unapproved CAN sender can interfere with the CAN singals and cause all sorts of problems. Maybe your MGV dongles are causing the problems?

FWIW I was just about to get one for me to use MGV, but decided against it. Couldn't really see the benefit, for the possibility of bricking the car.
worth a double check on monday on the way home from work, but it still did it with the adapter out last week and again today on a similar left hander on a road I don't use often. I am not bothered, it's nice to know it works. wonder if it puts the brake lights on as it does it though?
I dare say running the higher tyre pressures does not help, as after last weeks dealer visit where they let them down to 37 all round, it was less susceptible to it until I pumped them back up the day after.
Yes, I have had this yesterday and today.

My LH front tyre is under-inflated relative to the RH front, and I am 95% sure this is the reason.

As the car rolls, the weight comes off the less inflated LH tyre making it roll slower whilst at the same time it takes the shorter line in the bend, while the RH tyre compresses and also follows the longer line making it rotate quicker.

Do these things together, and squirt the accel at the same time, and the car thinks the RH is losing grip.

I shall confirm in the next few days when I get around to re-inflating the tyres correctly.
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LF was 37 psi and RF was 39psi. Not much in it really.

Put LF to 43psi and RF to 42psi, trying to reverse the bias, and I could still get the traction control to 'light up' but needed a more aggressive pull, and also was much more mild when it did cut in, barely noticed in fact.

Also to note, I have recently had the rear tyres replaced and noted that they had a noticeably larger rolling radius, so maybe there is a front-rear size difference effect too. Will have to wait for the winter tyres to go back on before I am back to same tyre rolling radius front-back for any further tests.

I know my Subaru had to have tyres within 5mm same diameter else the VDC system started to flag up issues too.
I know my Subaru had to have tyres within 5mm same diameter else the VDC system started to flag up issues too.
That's better then Volvo's XC70 (first model, 2000-2007?) where the middle differential would be damaged if I remember correctly...

EDIT: or was it the transfer case?
If I tip it in at 42 it will bong the brakes on mygreenvolt and the dash light will flash. If I do 40, it usually does not. Turn the stabilitrak and traction off though and it is fine.
Thats very similar speeds to where mine gets in a knot. I have a 270 degree snail shell shaped off ramp from my local motorway with slightly negative camber and a rough surface. The Ampera will go round smoothly at 40 mph but will jab the inside rear brake quite viciously at 42 mph. The Leaf however will take the same bend very comfortably at about 55 mph without any sign of traction control intervention.
I checked the tyres last week and N/S front was 37psi and all others 39psi. I adjusted them all to 39 psi with a separate gauge but the traction control still throws a fit on the same off ramp.
The Ampera is in for it's first service on Friday so I'll mention it, but don't expect any solution.
I have noticed mine still doing this, after a slight improvement from increased and adjusting tyre pressures.

I have never noticed this before, and the only change has been the rear tyres.

Be interested to hear from folks with this phenomenon what the tread depth is, front-to-rear, and if they are the same tyres. I'll make a guess that folks noticing this have less tread at the front than the back. If the car is picking up road speed from the rear wheels then it makes sense; it is already calculating the front tyres as 'running fast' and add in a sudden increase in turn circumference for the outer front, plus some sidewall compression, computer has a fit!
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I have a 'standardised' curve on one routine route I take, which, with the new Goodyear to the rear and old Michelin to the front, will trip the skid control at as low as 25mph on a dry road. This morning with the winter tyres on. matched all around, and a greasy cold road, I went around that same bend at 30mph with not a murmur of complain from the skid control.

I'm currently convinced this is an issue with the relative size of the rear tyres to the front. I never saw this with worn Michelins all around, and it was instant when I put the larger rolling radius GYs on the back. Now it's gone again with matched tyres.
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The initial symptoms sound a lot like when the NSF shock started to go on my old Focus. Worth getting checked if it persists.
We all seem to have the same symptoms, which go away with different tyres, so it seems to be a characteristic than a 'fault'.
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