Owner experiences steering and brake failure

[CyberGus]

Indeed it does but your criteria would leave probably 90% of drivers unable to own a vehicle. Vehicles have been generally easy enough to control even in failure modes that the average person can do so safely in most situations.

What happens when one of the 2M Teslas on the road has the HV pack fail? The screen blares "critical alert!" with instructions to pull over, the brakes get mushy, the steering gets mushy, propulsion loses power.

What happens in the Cybertruck? Same thing.

You think 90% of the population cannot handle that? Your opinion of mankind is even lower than mine lol

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[Stuck4ger]

@JBee …Airplanes quality check is insane. Imagine getting on a plane and seeing a panel gap or pilot screen completely going blank ….

I was told the Airbus 340 has 6 multifunction displays with redundant power and channels. There was NO WAY they could all fail at the same time and then one day in mid-flight that appeared to happen. It turned out that an engineer was told to program an automatic shutoff feature for if they were left on inadvertently. He didn’t want it to be annoying and simply picked a somewhat bizarre (and funny) 340 hours. Nobody realized the airline wouldn’t shut them off at the end of the day but simply turned their brightness down. So 340 hours later…

 

[BannedByTMC]

Your opinion of mankind is even lower than mine lol

I do find humans a generally disappointing species.

 

[Mini2nut]

If we could think of it, for these critical components, There's noway Tesla enginers would overlook it, otherwise it would be open for class action lawsuits.

Nearly impossible for owners to file a class action lawsuit against lawyered up Tesla. All Tesla buyers agree to arbitration for settling any issues.

"In the event of a concern or dispute between us, please send Tesla written notice to [email protected] describing the nature of the dispute and the relief sought. If it is not resolved within 60 days, Tesla and you agree that any dispute arising out of or relating to any aspect of the relationship between us will not be decided by a judge or jury but instead by a single arbitrator in an arbitration administered by the American Arbitration Association (AAA). This includes claims arising before this Agreement, including claims related to statements about our products. Alternatively, you may opt out of arbitration as described below."

https://electrek.co/2024/03/08/tesla-forces-another-class-action-customers-arbitration/

 

[CyberGus]

The original author of "catastrophe failure" has since deleted that Tweet, and followed it up with "no one was ever in the slightest danger".

While the facts of the incident remain unclear, it seems pretty obvious that the original post was laced with hyperbole, and the subsequent attempts to characterize the Cybertruck as "unsafe" are overblown.

 

[krispykreme]

I only joined this forum for this specific topic.

There is some basic mis conception here.

1. Both steering and brakes are consider ASIL-D system. Which means based on FIT calculation its shouldn’t fail in 10,000 year to 1.1M system (I can’t remember if brakes or steering is either class 1, class 2 or 3)

2. To have two independent ASIL-D system fail at same time is mathematically possible, but in reality highly unlikely.

3. I am not sure which suppliers provides the brake by wire for CT. But previous models I believe is Bosch- which did maintain mechanical connection to the brake booster with redundant loop to actual hydraulic pump. This system has been used for at least 10 years.

4. Tesla steering by wire has 2 redundant circuits and backup battery. So it’s highly unlikely that 48V system failure would simultaneously cut power to steering by wire as well as drain the backup battery.

Most likely is the OTA release bricked the vehicle control stack causing both brakes and steering system to fail. Highly doubt this is issue with both brake and steering subsystem.

I would be more concern with how the control software stack is tested, released, and what redudant check within the software stack as a whole.

 

[krispykreme]

The article was light on details and I haven't been able to follow if anything else has come out on this, but it does seem like there are a few posts about critical failures or system start issues that are concerning.

My take is that if the brakes (electric brake booster) and SbW system were heavy then the fault is in the 48 V system somewhere. In normal CANbus architecture systems, multiple ECUs will monitor the voltage system signal and trigger DTC errors for low or high voltage events but limited assist is only present when a fault is within the respective system itself. In the EPS that I work on, there can be three different kinds of faults due to internal diagnostics. Reduced performance, where overall operation is present, but some functionality is reduced or removed. Controlled shutdown, where there's a fast ramp down of EPS assist to zero, which can occur with torque sensor faults, and Immediate shutdown, where assist is taken away immediately. Steering fault feel is not an industry standard and is created as requested by the OEM, so I'm not sure what fault states Tesla is using, especially in the Cybertruck but it provide some information on what a steering internal fault would feel like.

Since the Cybertruck has a more centralized zonal system, the theory probably still applies. If the screen was still working, but throwing user visible errors to cease driving, I'm guessing the SbW went into limited assist mode due to some voltage fault and something similar happened to the electronic boost brake system. EPS steering systems can go into limited assist for any number of various reasons and that's just normal fault detection mitigation. The SbW hardware redundancies are present in case of SbW hardware component failures. Tesla said that each EPS powerpack is able to output enough torque to fully steer the vehicle, and under normal operation, each operates at half power. As JBee said, if both the brakes and steering to go into limited assist, then an anomaly is detected in the system outside of the steering or braking systems, and effectively "bypassing" the hardware redundancies.

For such safety critical systems, it would be nice if they were power isolated so this scenario wouldn't happen, but it can happen on a traditional 12V system. The only difference here is the SbW lack of physical redundancy. It would be nice to have a super cap or limited redundant battery on both systems that could provide full assist for a very short time when voltage faults are detected. I don't know that they don't exist, but this event suggests that something like that isn't present or the feature isn't implemented in this specific fault state.

The 48V system issue could be as benign as a BMS software issue affecting the charging cycle or something more serious like a bad wiring harness or traces in the board manufacturing. It's good that no one was hurt and the faults were detected and acted upon safely by the user, but it does warrant investigation and information dissemination to help bolster user confidence.

I doubt that 48V system failure would trigger both failure.

1. If CT still uses Bosch for the brake- there is mechanical linkage to the e-booster. And this system has been in use for at least over a decade.

2. CT steering by wire for it to fail- would also require the backup battery at steering to drain as well.

Both system shouldn’t fail simultaneously based on its ASIL-D certification. The only thing is control stack software.

While Tesla isn’t known to have backup power path to its ECU (anyone can go to Tesla store and see its HW 4 can verify that) I still find it nearly impossible to have the steering back up battery to also drain and fail.

 

[krispykreme]

We're going to hear every single story of every single cybertruck that has a hiccup or fault. The news agencies and negative folks out there won't have it any other way.

What have there been, maybe 10-15 that have had to be looked at by service? Less than 1%, that is for sure.

New cars have faults more often than folks think. It's just not normally plastered on the news, and customers typically are not tweeting at the CEOs of other car companies when their car needs service.

There is no story here.

I disagree.

Functional safety is a requirement for any vehicle on the road today.

Both ASIL-D system shouldn’t have failed simultaneously.

This isn’t how vehicle gets certified for road use.

 

[Dazureus]

I doubt that 48V system failure would trigger both failure.

1. If CT still uses Bosch for the brake- there is mechanical linkage to the e-booster. And this system has been in use for at least over a decade.

2. CT steering by wire for it to fail- would also require the backup battery at steering to drain as well.

Both system shouldn’t fail simultaneously based on its ASIL-D certification. The only thing is control stack software.

While Tesla isn’t known to have backup power path to its ECU (anyone can go to Tesla store and see its HW 4 can verify that) I still find it nearly impossible to have the steering back up battery to also drain and fail.

Do we know the full symptoms of the failure? I don't know the limp home conditions of a low voltage event to the brake booster, but I wonder if it could be something similar to a limited assist condition where the brake booster would still provide some boost, but less. Was it a total loss of assist to the brakes, and the user was only experiencing mechanical brake feel without the benefit of brake boost?

Likewise, was the SbW failure a complete loss of control or limited assist condition? It might not have been that the 48V system was completely drained and failed, but that the voltage monitor on the 48V system detected an anomaly and put 48V systems into limp home or fault, with each system providing whatever their low voltage fault states were.

Again, I couldn't determine if the user experienced complete dead stick or limited assist on the 48V systems. The Tesla patent for their SbW systems doesn't mention any power back up system independent of the main HV or mid volt system, but that also doesn't mean it doesn't exist. I think more details are needed and hope they're provided.

 

[krispykreme]

Do we know the full symptoms of the failure? I don't know the limp home conditions of a low voltage event to the brake booster, but I wonder if it could be something similar to a limited assist condition where the brake booster would still provide some boost, but less. Was it a total loss of assist to the brakes, and the user was only experiencing mechanical brake feel without the benefit of brake boost?

Likewise, was the SbW failure a complete loss of control or limited assist condition? It might not have been that the 48V system was completely drained and failed, but that the voltage monitor on the 48V system detected an anomaly and put 48V systems into limp home or fault, with each system providing whatever their low voltage fault states were.

Again, I couldn't determine if the user experienced complete dead stick or limited assist on the 48V systems. The Tesla patent for their SbW systems doesn't mention any power back up system independent of the main HV or mid volt system, but that also doesn't mean it doesn't exist. I think more details are needed and hope they're provided.

I do agree no one knows actual failure mode is.

But brakes does have mechanical linkage to e-booster. Hence the vehicle will still have full brakes.

I vaguely recall it does have a backup battery for the steering. I need to find where the article is.

 

[krispykreme]

Do we know the full symptoms of the failure? I don't know the limp home conditions of a low voltage event to the brake booster, but I wonder if it could be something similar to a limited assist condition where the brake booster would still provide some boost, but less. Was it a total loss of assist to the brakes, and the user was only experiencing mechanical brake feel without the benefit of brake boost?

Likewise, was the SbW failure a complete loss of control or limited assist condition? It might not have been that the 48V system was completely drained and failed, but that the voltage monitor on the 48V system detected an anomaly and put 48V systems into limp home or fault, with each system providing whatever their low voltage fault states were.

Again, I couldn't determine if the user experienced complete dead stick or limited assist on the 48V systems. The Tesla patent for their SbW systems doesn't mention any power back up system independent of the main HV or mid volt system, but that also doesn't mean it doesn't exist. I think more details are needed and hope they're provided.

https://www.autoevolution.com/news/...cybertruck-s-steer-by-wire-system-225607.html

This is where I got info from.

But no one knows for sure.

If Tesla does forgo power redundancy to both system, there is a serious problem with FMVSS and NHTSA that certified CT roadworthy.

Then again- nothing Tesla in terms of lack redundancy surprises me.

FSD will never reach L3 due to lack of redundancy in sensor suite, compute, software stack. Because by ISO26262- any system sits above brake/steering will also needs to be ASIL-D. The current HW 4 failed for lack of different power path, homogenous SOC, and on same PCBA.

Hopefully when I get my beast- I can take a look at the SBW.

 

[Jhodgesatmb]

We're going to hear every single story of every single cybertruck that has a hiccup or fault. The news agencies and negative folks out there won't have it any other way.

What have there been, maybe 10-15 that have had to be looked at by service? Less than 1%, that is for sure.

New cars have faults more often than folks think. It's just not normally plastered on the news, and customers typically are not tweeting at the CEOs of other car companies when their car needs service.

There is no story here.

Of course there is a story. The story is that a new design with many new technological advances will produce issues that need to be identified and fixed. By this time next year we will not have these problems anymore. The people who get the first 20,000 Cybertrucks really are on the vanguard and it is unfortunate that they (and the media) think that buying early like this entitles them to a perfectly running vehicle with all the software features, etc. Believing it doesn't make it real. Although I am champing at the bit to get my Cybertruck, there is a part of me that is happy to be a bit back in line. Is it enough? I don't know. I would not want to be stranded on a trip or to put my family at risk in any way so it is a tough call. Fortunately we have the Model Y that we can use.

 

[Jhodgesatmb]

https://www.autoevolution.com/news/...cybertruck-s-steer-by-wire-system-225607.html

This is where I got info from.

But no one knows for sure.

If Tesla does forgo power redundancy to both system, there is a serious problem with FMVSS and NHTSA that certified CT roadworthy.

Then again- nothing Tesla in terms of lack redundancy surprises me.

FSD will never reach L3 due to lack of redundancy in sensor suite, compute, software stack. Because by ISO26262- any system sits above brake/steering will also needs to be ASIL-D. The current HW 4 failed for lack of different power path, homogenous SOC, and on same PCBA.

Hopefully when I get my beast- I can take a look at the SBW.

I wonder about statements like "FSD will never reach L3 due to lack of redundancy" when we know that Tesla uses camera and that they are redundant and that they have 2 computers doing FSD that back each other up. If ISO26262 and FMVSS/NHTSA require redundancy in brake systems, and I have no reason to surmise otherwise, then they do.

 

[krispykreme]

I wonder about statements like "FSD will never reach L3 due to lack of redundancy" when we know that Tesla uses camera and that they are redundant and that they have 2 computers doing FSD that back each other up. If ISO26262 and FMVSS/NHTSA require redundancy in brake systems, and I have no reason to surmise otherwise, then they do.

1. That is because Tesla has been hiding under L2 in all of their legal disclaimer. In that sense- human driver sits above and final responsibility over the vehicle control. Hence its “FSD” is never have final responsibility and control.

2. ISO 26262 principle is very clear. Any system above an ASIL-D system will be to be ASIL-D.

For L3, the compute or vehicle control systems sits above brake and steering needs to be full ASIL-D compliant.

3. As I mentioned above- HW 4 failed due to same homogenous SOC, same PCBA, and common power source. That is a no no from compute point of view. Been there and done that.

4. Have multiple camera is not redundancy. Because same with homogeneous SOC above. Camera sensor have same failure mode- you can’t see in bad weather conditions. That is not how redundancy work.

5. Tesla was never certified for L3. Nor it has achieved any permit to test and collect data for L3 on public roads.

6. That is reason why both CA DMV and US department of justice is going after Tesla.

 

[Jhodgesatmb]

1. That is because Tesla has been hiding under L2 in all of their legal disclaimer. In that sense- human driver sits above and final responsibility over the vehicle control. Hence its “FSD” is never have final responsibility and control.

2. ISO 26262 principle is very clear. Any system above an ASIL-D system will be to be ASIL-D.

For L3, the compute or vehicle control systems sits above brake and steering needs to be full ASIL-D compliant.

3. As I mentioned above- HW 4 failed due to same homogenous SOC, same PCBA, and common power source. That is a no no from compute point of view. Been there and done that.

4. Have multiple camera is not redundancy. Because same with homogeneous SOC above. Camera sensor have same failure mode- you can’t see in bad weather conditions. That is not how redundancy work.

5. Tesla was never certified for L3. Nor it has achieved any permit to test and collect data for L3 on public roads.

6. That is reason why both CA DMV and US department of justice is going after Tesla.

It seems to me that Tesla is certified for L2 because it is not safe for L3 and not because of hardware. I am sure that you are right about the hardware systems and I am not arguing it. I do not see how whether the cameras render effectively in bad weather has anything to do with redundancy. If you look at the Tesla camera coverage diagrams (which may or may not be correct but that is what they publish) there is overlap on all of their camera coverage so there is some degree of redundancy.

I do not know why we are even talking about this. You are clearly not a supporter of FSD and maybe not even Tesla. I am a realist and not a blinded fanboy. I know that federal regulations must be adhered to and that if Tesla wants to do business it will adhere to them. You seem to have a conspiracy theory attitude that I just don't follow.

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