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Hyundai Kona convert...
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I've just been to collect my Ampera from Thurlow Nunn Milton Keynes where the driver's door button was being fixed under warranty. 2 miles into the 12 mile trip home, going round a roundabout (you've been to MK then?), there was a 'warning bong' from the car and 2 x error lights came up: 'Service Stabilitrak' (traction control?) and 'Service Brake Assist' they said.
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Anyone had any experience of these ailments?

I parked up and locked / unlocked a couple of times to see if it was an 'over-eager' sensor, but to no avail. I was wondering if these errors self-correct after a couple of charges, or will I need to take it back to MK again? The car seems fine: same pedal feel, no vagueness on corners etc..

It's ironic really: After 32 months and 62K miles the car has been SO reliable. it's almost as if a sneaky mechanic pushed a screwdriver somewhere he shouldn't....but they wouldn't do that would they?
 

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Haven't seen that one on the forum, but it sounds like a wheel speed sensor, if you check the error codes it should poin to one of the wheels. They are not expensive and are usually a DIY job to change unless they get corroded in then it's a nightmare best left to someone else.
My VW does the same thing on a regular basis as I don't drive it enough a quick clean ususallly sorts it out.
 

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Hyundai Kona convert...
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Discussion Starter #3
Thanks @black amp, the Volt forum supports the theory of Wheel Speed Sensor fault. Not sure if this is a Vauxhall or a local garage fix tho...
 

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Happened to me once when the 12v battery was over drained, you might want to check the output of the battery, maybe it's not accepting charge
 

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Hyundai Kona convert...
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Discussion Starter #6
Checked the 12v battery - 12.6V. Mine is one of the 2014 models and (touch wood), doesn't appear to have been victim of the battery gremlins. Wheel Speed Sensor being investigated end of this week: fingers crossed it'll be sorted.
 

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Hyundai Kona convert...
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Discussion Starter #9
I had 2 new (rear) tyres fitted on Thursday: they'd done 63K miles in 33 months - still plenty of tread but one had a bulge...
I took the opportunity to check out the Wheel Speed Sensors. Spot anything?
upload_2017-3-5_15-39-22.png


Questions:
1) Could this really have taken 63K mile to show itself as a problem?
2) The car is 3 months inside it's 3 yr warranty. Warranty claim yes or no?
Frustrations:
Despite the obvious fault - Thurlow Nunn (Milton Keynes) insist on having the car for a whole day - and advised me that they will charge me £78 for diagnostics if they don't think it's a warranty issue. When I pointed out the obvious fault - they insisted, saying it was 'their process'. Car now booked in on 24th March.....the first date they had a courtesy car free. Not impressed!
 

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I had 2 new (rear) tyres fitted on Thursday: they'd done 63K miles in 33 months - still plenty of tread but one had a bulge...
I took the opportunity to check out the Wheel Speed Sensors. Spot anything?
View attachment 24257

Questions:
1) Could this really have taken 63K mile to show itself as a problem?
2) The car is 3 months inside it's 3 yr warranty. Warranty claim yes or no?
Frustrations:
Despite the obvious fault - Thurlow Nunn (Milton Keynes) insist on having the car for a whole day - and advised me that they will charge me £78 for diagnostics if they don't think it's a warranty issue. When I pointed out the obvious fault - they insisted, saying it was 'their process'. Car now booked in on 24th March.....the first date they had a courtesy car free. Not impressed!
Answer -1 - yes
Answer -2 - definitely, it should have been adequately secured at the point of manufacture, and definitely picked up on any of the previous 2'services.

Dealers are almost always looking to cover their backsides financially, the joys of franchises, they always get left holding the baby if the manufacturer pushes back.
 

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Had the same symptoms.
Abs sensor cable.
I buyed the sensor cable original one for 30Eur. But after two days the car has fixed by it self.
Just erased with diagnostic those faults
 

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I'm not crazy, the attack has begun.
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Go to the person you bought the car off, and show them that it was not of fit quality when you bought it. They are liable for 6 years and should pay for this.

It is a design defect. The vendor is responsible.

If you used a credit card for a deposit, and/or loan, then also tell them and ask for them to fund the diagnosis and repair.

Thanks for the flag. I guess you've just made us all responsible to go check this for ourselves now, lest we be accused of not preventing this damage. (Thanks! :rolleyes::sneaky:)
 

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I'm not crazy, the attack has begun.
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...Of course the other thing to say to them, assuming you used them to service the car previously, is "Why did you not warn me of this issue when you serviced it last and gave it a clean bill of health?"

It wouldn't be like they had no chance of avoiding it. They're the ones under the car, on a ramp. Why should YOU have to spot this?
 

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I've just been to collect my Ampera from Thurlow Nunn Milton Keynes where the driver's door button was being fixed under warranty. 2 miles into the 12 mile trip home, going round a roundabout (you've been to MK then?), there was a 'warning bong' from the car and 2 x error lights came up: 'Service Stabilitrak' (traction control?) and 'Service Brake Assist' they said.
.
Anyone had any experience of these ailments?

I parked up and locked / unlocked a couple of times to see if it was an 'over-eager' sensor, but to no avail. I was wondering if these errors self-correct after a couple of charges, or will I need to take it back to MK again? The car seems fine: same pedal feel, no vagueness on corners etc..

It's ironic really: After 32 months and 62K miles the car has been SO reliable. it's almost as if a sneaky mechanic pushed a screwdriver somewhere he shouldn't....but they wouldn't do that would they?

We had a complete brake failure a couple of weeks ago when my wife was driving our 2014 Ampera. Pedal to the floor and "The Service Brake Assist" MIL on. Only stopped by applying the parking brake. Very Scary!!!
Turned the car off, left it for a few hours, and fault disappeared when she turned it on again.
Car put on a recovery vehicle and taken to dealer waiting for a response from Vauxhall.
Goggle Chevy Volt brake failure and you will see that this appears that Chevy know this to be a problem as they have had numerous examples of the same fault.
It's a shame because the car has been terrific up to the incidence of brake failure and now my wife is terrified of it.
Be careful!!!
 

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Hyundai Kona convert...
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Discussion Starter #15
Fixed under the Lifetime Warranty (now over 65K miles and approaching 3 years). That's one example of where the Lifetime warranty worked! Anyone think of another?
 

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We had a complete brake failure a couple of weeks ago when my wife was driving our 2014 Ampera. Pedal to the floor and "The Service Brake Assist" MIL on. Only stopped by applying the parking brake. Very Scary!!!
Turned the car off, left it for a few hours, and fault disappeared when she turned it on again.
Car put on a recovery vehicle and taken to dealer waiting for a response from Vauxhall.
Goggle Chevy Volt brake failure and you will see that this appears that Chevy know this to be a problem as they have had numerous examples of the same fault.
It's a shame because the car has been terrific up to the incidence of brake failure and now my wife is terrified of it.
Be careful!!!
Sounds like a faulty Electronic Brake Control Module that has been noted on US Volts. Scary that this fault can be allowed to happen. I thought all brakes had a fallback to fail in a safe mode.
 

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Sounds like a faulty Electronic Brake Control Module that has been noted on US Volts. Scary that this fault can be allowed to happen. I thought all brakes had a fallback to fail in a safe mode.
Hi thanks for your feedback.
The Vauxhall Ampera/Opel/Chevrolet Volt has a "brake by wire" system designed and manufactured for GM by ZF TRW in the US.
It is a very advanced "Slip Control Boost" system specifically designed for EV's and Hybrids that do not have a vacuum boost generated from the ICE.
This Slip Control Boost system utilises an Electro-Hydraulic power pack, linked to an accumulator, and throttle simulator module.
The actual Electronic Control Brake unit you refer to (ECB 460 premium architecture electronic brake control module) looks at all the input from these systems and also from the regenerative braking traction motor, several accelerometers, wheel speed sensors, etc. and it decides how to best distribute the hydraulic forces to each wheel cylinders dependant on its imbedded algorithms.
The ECB provides simulated feed back to the driver via the foot pedal unit.
Although the drivers pedal is also connected to the twin cylinder master cylinder, it only acts as a displacement transducer. Should a catastrophic failure of the hydraulics within the SCB systems occur there is a final fail safe via the 4/2 wheel push through which comes in at the very end of the stroke of the master cylinder.
Recognising that there would be no hydraulic or other attenuation one would have to apply enormous pressure right at the end of the pedal travel to it to try and stop the car. (Try driving a modern car without the power steering working!)
The failsafe may well have worked but my wife certainly would not have had the strength to apply sufficient pressure to stop the car and would certainly had the impression that the pedal "went all the way to the floor" .
Eden Branksome, and the Technical team at Vauxhall Amprea have been excellent, recognising that this is a very complex braking system to diagnose, and that the vehicle reset itself immediately after the incident and now appears to behave normally. However, that did manage to lift a retained OBDII DTC fault code to substantiate the brake failure.
Several parts within the Slip Control Boost hydraulics system are being replaced as is the whole ECB unit.
I agree that this is a safety critical fault and that GM should be seriously considering issuing a product recall as they have plenty of evidence in the States of the same failure that we have recently experienced.
However well done Vauxhall UK.
 

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What's of more concern is that there is a combination of inputs into the system that can force it to this failed state from which it recovers once the inputs are removed / reset by a restart. Replacing the system components won't necessarily fix the problem as the exact root cause can't be determined from a DTC fault code.
Given the systems behaviour of working normally immediately following a reset suggests a problem with the systems response to a soft error condition that it's not handeling correctly. finding a root cause and fix very very difficult if not impossible given the relatively small number of events compared to the millions of sucessful brake applications every day across the world the chances of getting to this state must be several million to one.

I think a recall is unlikely simply because there is no fix to apply at the moment.
 

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Hi thanks for your feedback.
The Vauxhall Ampera/Opel/Chevrolet Volt has a "brake by wire" system designed and manufactured for GM by ZF TRW in the US.
Great informative description of the braking system @Lynx IV
Do you work for ZF TRW or are you spawn of the @donald ? :p
 

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Great informative description of the braking system @Lynx IV
Do you work for ZF TRW or are you spawn of the @donald ? :p
Hi Russ and no I do not work for ZF or GM but I was the UK Systems Manufacturing Manager for the largest hydraulics company in the world a few yeas ago before building my own successful precision component manufacturing business.
I have been involved in many diverse projects and can normally understand and interoperate complex integrated systems used in many of todays industries.
Mike
 
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