It would be nice if our cars we're just a software update (which is what I think is the real problem).

 

Different supplier, different software, different problems, totally irrelevant to Corvette.

 

I'll accept your judgement on that, but...

When you add the surprise factor to a sudden increase in steering effort, there will be accidents.
Some people are dolts and can't handle anything unusual.
Others are very sharp but get caught at the wrong moment or under the wrong conditions, and it gets them.

Anything mechanical can and will fail when you have hundreds of thousands of items being produced. But if GM or any other auto maker thinks that steering assist failures aren't a big deal, the courts will straighten them out big time.
They didn't think ignition switches that occasionally turned themselves off were a big deal.

 

Don't get me wrong. It's a HUGE customer dissatisfaction issue (loss of assist). It's just not a safety/regulatory issue.

My post above was more inline that just because the K2XX trucks are getting a software fix in their Nexteer gear, this doesn't mean anything about the Y1XX/A1XX (Corvette being Y1XX) since it's a Bosch gear.

Different suppliers use totally different EVERYTHING. I know people buy cars and all and expect the OEM to be responsible for parts, but in the chassis systems (Brakes, Suspension, and Steering) you are more likely to find things be cross OEM (due to supplier) than cross supplier (due to OEM).

So the K2XX issue should worry F-150 and Ram owners more than Corvette owners, because it's the same supplier (Nexteer supplies ALL the light duty pickups for the Big 3). Corvette owners should be worried about M-Class (BR166) and a multitude of BMW products (which all use similar ECUs and underlying software) since they are all Bosch.

 

I had this on the DIC I just hit the dismiss button and finished my last 500 miles of my trip. Will have a dealer check for codes next time I bring it in. I was going 65-70 mph when it went off. Didn't notice any change in the steering.

 

I'll try as I did in post 116 to suggest NOT A SOLUTION but a Temporary Software Patch! Perhaps I didn't explain what was used in a microprocessor pulsed MIG welder properly.

As stated this is NOT a solution but a temporary patch so you're not having to drive a car that all of a sudden doesn't have power steering. Would not work for all situations but many posted here say when they restart the Vette the steering works for a while. This is obviously a transient failure of some type BUT if it can fix itself after starting at least for a short time they can change the software so whatever is shutting the system completely off, turns it back on and then displays go to the dealer as soon as possible! It they think folks might not do that indicate this "patch" will only work for 4/5 more starts etc.

SIMILAR ISSUE:
We had an unexpected problem occur with a microprocessor based Pulsed MIG welder in the 1990's. We sold two systems making spot welds in an automated line producing food freezing belts. It occurred once every day or so but the arc would flare and destroy a belt link, stopping the assembly line and requiring several hours to repair and get going.

Watched as our engineer, who designed the system, duplicated the problem in our Lab. It was occurring randomly once in ~thousand welds. He could not understand how it happened and went through his software and documentation many times.

He was a good friend and very frustrated, kept telling me what he observed can't happen! I asked, "If you can't find it, can you put in code that if it ever happens (even though your software says it can't) will shut the system down instead of having the power spike that creates a hole in the belt link?" He did! He never understood why it was happening in the first place but prevented a destroyed part the occasional time it did and most important the hours it took to get the line restarted after a section had to be removed. They just hit the green start button again!

Therefore, for the Vette power steering, if it's an intermittent issue in whatever component or ground, why not turn the system back on and have a warning message but not leave it with no power? Just Sayn'.

Also reminded of a recent tour of a power company sub station. The engineer mentioned why occasionally, when you get a power outage you'll get a spike a few seconds after the outage and sometimes the power stays on sometimes not! If there is a current surge, the system will shut down. But if it was caused by a tree branch or squirrel getting across a line they try to re-energize the line and perhaps burn the branch or dead squirrel to a crisp! They may do that two times before shutting it down if that doesn't clear whatever created the short!

 

Where we disagree is that I think sudden loss of steering assist is a safety problem under some conditions. Not as bad as having a wheel fall off or something like that, but most of the motoring public has a difficult enough time paying attention to driving, so any sudden problem won't even get full brainpower applied for several seconds. Traffic sometimes doesn't allow much time before solving the problem. Usually, either skill or dumb luck will prevent disaster. Sometimes, they won't.

Going back to my ignition switch example, it took a long time for the full ramifications of that problem to be properly recognized. Depending on how often the steering problems occur, we may be in the same condition.

Time will tell. I'd like to be wrong.

 

The first time it happened was a bit of a shock but it happened in a parking lot, low stress environment. Now that it's a regular occurrence (2-3 times/day) it's a non issue (safety wise). I can say however, that the car is a total pain to steer. It takes some serious effort to get it pointed in the correct direction taking right angle turns etc in my daily commute. Someone with less upper body strength (my wife for example) would not be able to drive the car in this condition and could certainly be the cause of a crash when it occurs unexpectedly.

 

Doesn't have to be regulatory! I'm sure the first person who hasn't been lifting for 35 years turns a corner and the assist stops there will be a lawyer involved. They are probably waiting for enough to happen so they can make it a class action suit or when someone gets really hurt before they line up clients!

As I posted in #186, since many start to work when they restart the car, NOT A FIX but they should try to restart the system and post a warning message to see a dealer, etc. At least for some it may avoid an accident!

Even though I have been lifting for 35 years, when I drive my street rod with a higher ratio, none assisted rack and pinon it takes much more strength. But there I am anticipating and don't make fast turns!

 

I think you mean to say, could become a safety issue.

Technically until the ignition switch recall that wasn't a safety issue either.

It's a nuanced difference but an important one.

 

Jerry,

Tons of cars have already lost assist, from tons of manufacturers already. Some have been recalled, but none of them have been deemed unsafe or driven new regulations.

Not going to say that won't change, but as of now, government seems ok sitting around doing nothing. The lawsuits aren't moving the needle either, typically due to mitigating factors (lots of legal liability evaporates for an OEM if you as a driver admit to being inattentive.)

 

Understand but the "government' wasn't concerned about manganese in welding fumes until there was a class action suit by the folks who did asbestos class action suits. I consulted as an expert witness defending these and now the ACGIH has manganese fume (which is all steel) classified at such a low allowable level in an 8 hour day it's 4 times lower than Phosgene the WWI poison gas! Frankly to weld steel for an 8 hour day really requires a helmet that filters air (similar to car painters.) It's that way now in Canada but OSHA takes a bit more time to implement the latest max fume levels!

Just saying lawyers will be the driver! In any case my post #186 is a simple way to patch the issue for some where the power comes back on after an engine restart. Won't fix the problem but may help avoid, for some cases, someone making a turn and having the power steering fail!

 

I just updated the thread that I started originally but since so many people are on this one too I figured I'd update here as well:

The new rack finally came in and they replaced it yesterday; only time will tell if its a bad design or a group of bad parts that caused the issues for all of us. I've included the diagnosis portion of my repair order showing the code C0545-3a and GM telling the mechanic that there is a short in the torque sensor....I may have to go back though as it seems like my steering wheel is just a little off center...maybe.

 

Ditto:

Glad you finally got yours replaced. Mine has been working flawlessly so far and I DD it. I got an alignment after the replacement because I also lowered the car on the factory bolts and also took the opportunity to dial out some negative camber. Hopefully that will improve the lifespan of these tires.

 

NOT A PROBLEM!!! REALLY!!!
Maybe you better take a look at some of the complaints about the electronic PS on the Chevy Pickup trucks.
People stating they were turning when all of a sudden the steering wheel jerked out of their hands and they went up and over the side walk stopping just short of hitting a retaining wall!!!
What if someone had been walking on the side walk?

What is happening is if the voltage gets below 9 volts on the PS the whole electrical systems shuts down and resets, which can cause a whole host of problems especially if you are not expecting it.

The reason this usually happens a lower speed is because the alternator is turning slower and providing less current.

GM's solution (JOKE) is to reprogram the control module.

Well what happens when down the road the alternator goes out! or the battery shorts?

This is an accident just waiting to happen.

GM recalled over 700,000 thousand trucks because of this issue.

You better believe it is a problem!!!

 

The truck recall is due to a loss of steering assist due to low vehicle voltage, specifically going under 9 volts.

The steering wheel wouldn't jerk out of your hand, anyone who says that is exaggerating. What does happen is assist gets very heavy, very quickly. If the suspension is wound up (you are in a turn) and you don't have a firm grip on the wheel the suspension will unwind a little (which probably surprises most people). However as you go faster the windup is less because you don't load up your suspension as much (notice your steering angles at various speeds). That's physics, and can't be changed.

GM cars in general have voltage issues due to "undersized" alternators (my technical opinion). So in that regard it's not a steering problem, but an electrical system problem. Slap a larger alternator on your car if you don't like that.

Basically, people should not be one fingering their steering wheel and driving while multi tasking. If you can't transition to one hand firmly on the steering wheel quickly at any speed then yea it's probably surprising and the vehicle might behave weirdly. But in that instance it is entirely driver inattentiveness which is the problem. The expectation that you don't need to actually drive your car while you are driving is the problem, not the part failure. I say this as a customer and an engineer.

If you can't pay attention to driving then don't drive. We need to start taking people's licenses away for being distracted. End of story. The car cannot drive its self and all failures assume an attentive driver in the loop who can take control of the vehicle and safely stop it.

 

What d YOU think should be done? I assume you want a hydraulic system retro fitted?


Well what happens when down the road the alternator goes out!
- You will lose assist. Do you think you are the only one who has thought of this failure condition? You think they have not tested to make sure that the majority of people can still steer with the force required?


or the battery shorts?
- No sure what this has to do with anything but if the battery shorts and there is no fuse in the current path...loss of power steering will be secondary to the explosion.

 

I think many people are under the impression that everything in a car is manual and mechanical. It's not. If you have power supply issues from the battery and the alternator lots of stuff starts to go wrong. the days of saying oh my battery is bad so I have dim headlamps are long gone. Those electrons are very important.

 

The steering wheel wouldn't jerk out of your hand, anyone who says that is exaggerating. What does happen is assist gets very heavy, very quickly. If the suspension is wound up (you are in a turn) and you don't have a firm grip on the wheel the suspension will unwind a little (which probably surprises most people). However as you go faster the windup is less because you don't load up your suspension as much (notice your steering angles at various speeds). That's physics, and can't be changed

There are several people that have complained that when the electrical system reset the wheel jerked violently. Of course violent is subject to opinion, but this is not just one person saying this.

I agree 100% about putting a better alternator on.

"If you can't pay attention to driving then don't drive. We need to start taking people's licenses away for being distracted. End of story
Basically, people should not be one fingering their steering wheel and driving while multi tasking."

Ok, that is a nice pipe dream, but we all know that is never going to happen. Lets stick with reality.

Most folks cruising down the road do not constantly have their hands at 10 and 2 on the steering wheel. They are barley touching the wheel especially cruising on the interstate. If the car suddenly turns off, some are going to over react, and I hope you, me or anyone else is not beside them when they do.

 

If you don't at least keep one hand on the wheel "relaxed" then you aren't in control. Switching from "relaxed" to one hand gripped is very simple (involved closing the hand over the rim). People who do not have one hand visibly on the wheel should be ticketed, if this happened more often driving habits would change.

Suspension wind up would cause the wheel to wind backwards in your hand, slightly (unless at full lock, then it could be a 1/4 of a turn). Torque wind up (in the steering gear) would contribute to this at ramp down but you'd see a more significant jerk is when assist ramps back in, this is because you are placing 5-10 Nm on the wheel and then assist comes in and if ramped too quickly will "over gain" your intent (as in a working system you rarely put in more than 4 Nm of torque). This would cause a "jerk" in the wheel as you all of a sudden get way more angle than you anticipated (due to the sudden increase in gain).

The torque sensor "issues" can be solved by proper ramping in and out assist and controlling it that way (as your torque input would relax as gain slowly comes back in).

Steering works on a simple phenomenon, your input torque is measured and a gain is applied (based on your torque and vehicle speed), this gain is then transmitted to the rack (or column) by the motor (thru a reduction gear, on rack usually a belt and ball nut). The total system force is therefore the driver torque plus the assistance torque. As assistance torque is ramped out driver torque increases, if there is a sudden drop of assistance torque the drivers torque will increase suddenly. This would not feel like a jerk, rather it would feel like a "wall" or as people used to call a "catch." The reverse as I explained above happens when assist comes back in, the driver torque is reduced and the assistance torque is increased. If this is again done suddenly the driver is "requesting" too much torque and you get a giant "step input" on the gain. This leads to a sudden "jerk" in the wheel as the steering speed (which is the 2nd derivative of the system, the first being angle, the original being torque) increases at a very fast rate. Once the drive compensates (by lowering torque) the system stabilizes and returns to normal.

These sort of things applied to hydraulic as well, however since fluid flow couldn't be a step input unless you had a cut line the resulting ramp rate was always very slow, and therefore of little surprise to the driver. The surprise factor of a sudden loss is the unnerving part to most customers, but if you are paying attention (even with a relaxed hand on the wheel) then it shouldn't be an issue.