Power steering failure
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 35,046
Likes: 12,412
From: NE South Carolina
^^^
With high peak flow amps to handle a quick move can see why our BMW has a small battery next to the large AGM in the rear! It's in series with the main battery for the steering so current is cut in half! Fewer ground issues!
With high peak flow amps to handle a quick move can see why our BMW has a small battery next to the large AGM in the rear! It's in series with the main battery for the steering so current is cut in half! Fewer ground issues!
Instructor
Joined: Apr 2008
Posts: 196
Likes: 32
DC versus AC motors. The Power Steering Motor its self is probably the most robust part of the electronics. It's just a copper wire stator and a permanent magnet rotor. The parts that will most likely fail are the sensors, specifically the torque sensor (which is located on the input shaft, it's the reason for the cable coming out of that side of the gear) that reads your torque (the driver torque) or the motor/rotor sensor which is inside the electronics but measures the movement of the motor (and thus allows for closed loop control of the motor).
Both of those failures are pretty permanent though, you won't recover from them. These failures all are of the type where the system either recovers during the cycle or on the next cycle suggesting they are either temporary (temp or voltage related) or are latched.
If anything were to "burn out" in an AC motor system it would be the power electronics which convert DC to AC. They consist of 6 MOSFETs in a bridge configuration with 3 high side and 3 low side drivers. The MOSFETs are switched on and off in a variable duty cycle to create 3 AC signals which using a space vector control the motor (since it's a 3-phase system not a single phase, think the AC on the power pole versus the AC in your house).
Both of those failures are pretty permanent though, you won't recover from them. These failures all are of the type where the system either recovers during the cycle or on the next cycle suggesting they are either temporary (temp or voltage related) or are latched.
If anything were to "burn out" in an AC motor system it would be the power electronics which convert DC to AC. They consist of 6 MOSFETs in a bridge configuration with 3 high side and 3 low side drivers. The MOSFETs are switched on and off in a variable duty cycle to create 3 AC signals which using a space vector control the motor (since it's a 3-phase system not a single phase, think the AC on the power pole versus the AC in your house).
Thank you again
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
Two More PS Failures Today
Driving in stop/go traffic on hot morning, 90+ degrees, after 5 miles PS failed. Pulled into parking lot and parked in shady spot, then raised hood and waited 10 minutes. Restarted with no problems and tried to get out of traffic but couldn't and PS failed again after another 5 miles.
Same procedure: pulled into parking lot and found shade to park. Lifted hood, waited 10 minutes and restarted with no problems. Got out on open road and sped up to 60 mph. No problems for next 30 minutes until got home.
So clearly this is an overheating problem probably messing up the software controlling the PS motor. Until the overheating is fixed, nothing is going to fix this.
Driving in stop/go traffic on hot morning, 90+ degrees, after 5 miles PS failed. Pulled into parking lot and parked in shady spot, then raised hood and waited 10 minutes. Restarted with no problems and tried to get out of traffic but couldn't and PS failed again after another 5 miles.
Same procedure: pulled into parking lot and found shade to park. Lifted hood, waited 10 minutes and restarted with no problems. Got out on open road and sped up to 60 mph. No problems for next 30 minutes until got home.
So clearly this is an overheating problem probably messing up the software controlling the PS motor. Until the overheating is fixed, nothing is going to fix this.
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
I am writing as a lawyer
[QUOTE=VistaVette;1595181879][QUOTE=LT1 Z51;1595181757]Just because you never saw a failure doesn't mean it didn't happen.
If I don't notice it, I don't care. If it happens when I'm driving and I don't have power steering, or any system for that matter, it's not acceptable.
I really appreciate the explanations on these systems, it's valuable and interesting but I think you're writing as an engineer, not as a consumer/end user. I won't put up with any system in my car failing, intermittently or otherwise, nor should I have too. GM can either get it right or buy it back.
I will guarantee to you or GM that this problem is going to result in massive legal liability. PS going out suddenly and without warning is just completely outside legal norms -- res ipsa loquitur. GM needs to fix this now!
If I don't notice it, I don't care. If it happens when I'm driving and I don't have power steering, or any system for that matter, it's not acceptable.
I really appreciate the explanations on these systems, it's valuable and interesting but I think you're writing as an engineer, not as a consumer/end user. I won't put up with any system in my car failing, intermittently or otherwise, nor should I have too. GM can either get it right or buy it back.
Pro
Joined: Mar 2005
Posts: 638
Likes: 192
From: Las Vegas NV
Two More PS Failures Today
Driving in stop/go traffic on hot morning, 90+ degrees, after 5 miles PS failed. Pulled into parking lot and parked in shady spot, then raised hood and waited 10 minutes. Restarted with no problems and tried to get out of traffic but couldn't and PS failed again after another 5 miles.
Same procedure: pulled into parking lot and found shade to park. Lifted hood, waited 10 minutes and restarted with no problems. Got out on open road and sped up to 60 mph. No problems for next 30 minutes until got home.
So clearly this is an overheating problem probably messing up the software controlling the PS motor. Until the overheating is fixed, nothing is going to fix this.
Driving in stop/go traffic on hot morning, 90+ degrees, after 5 miles PS failed. Pulled into parking lot and parked in shady spot, then raised hood and waited 10 minutes. Restarted with no problems and tried to get out of traffic but couldn't and PS failed again after another 5 miles.
Same procedure: pulled into parking lot and found shade to park. Lifted hood, waited 10 minutes and restarted with no problems. Got out on open road and sped up to 60 mph. No problems for next 30 minutes until got home.
So clearly this is an overheating problem probably messing up the software controlling the PS motor. Until the overheating is fixed, nothing is going to fix this.
Pro
Joined: Mar 2005
Posts: 638
Likes: 192
From: Las Vegas NV
An update on my issue: The dealer has ordered a new complete power steering rack and module and will install it once it arrives. Until then I have my car to drive. Of course, it failed as soon as I pull out of dealership.
Advanced
Joined: Jul 2016
Posts: 82
Likes: 14
From: Lake Mary Florida
I've just had a PS failure on my 2017 Z06 - was traveling at 70mph about 10 minutes into journey. Pulled off at next junction and turned car off and straight back on again - issue was cleared and was ok for rest of journey home.
Car was built in September 2016 and currently has 10,000 miles on it with this being first instance of issue
Car was built in September 2016 and currently has 10,000 miles on it with this being first instance of issue
Pro
Joined: Mar 2005
Posts: 638
Likes: 192
From: Las Vegas NV
I've just had a PS failure on my 2017 Z06 - was traveling at 70mph about 10 minutes into journey. Pulled off at next junction and turned car off and straight back on again - issue was cleared and was ok for rest of journey home.
Car was built in September 2016 and currently has 10,000 miles on it with this being first instance of issue
Car was built in September 2016 and currently has 10,000 miles on it with this being first instance of issue
What drive mode we're you in?
What was the ambient temperature and humidity?
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Le Mans Master
Joined: Oct 2005
Posts: 7,002
Likes: 2,679
Originally Posted by PCMIII
I will guarantee to you or GM that this problem is going to result in massive legal liability. PS going out suddenly and without warning is just completely outside legal norms -- res ipsa loquitur. GM needs to fix this now!
The only legal body of work is the previous recalls ordered by NHTSA.
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
LT1 Z51
You couldn't be more wrong about GM's legal liability here. This is a matter of tort and contract law, not statutes or regulations.
Do you not remember what happened to Toyota and the sticking accelerators? Were there any statutes regulating that?
You couldn't be more wrong about GM's legal liability here. This is a matter of tort and contract law, not statutes or regulations.
Do you not remember what happened to Toyota and the sticking accelerators? Were there any statutes regulating that?
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
So a software issue on the motor control?
I lost my power steering today however I can't imagine it was heat related - I was driving at 70mph on the interstate and had only been running the car for 10 minutes with no spirited driving at all.
Got off at the next junction and turned car off and on again and issue solved.
Seems Lots of people with early 17 builds are having same issue.
Got off at the next junction and turned car off and on again and issue solved.
Seems Lots of people with early 17 builds are having same issue.
Advanced
Joined: Jul 2016
Posts: 82
Likes: 14
From: Lake Mary Florida
Ambient Temp was 78 and humidity 90% - central FL
Pro
Joined: Mar 2005
Posts: 638
Likes: 192
From: Las Vegas NV
Le Mans Master
Joined: Oct 2005
Posts: 7,002
Likes: 2,679
And if I remember about Toyota they only paid a fine, and otherwise have civil actions against them. However there are things in FMVSS relating to ETC.
Le Mans Master
Joined: Oct 2005
Posts: 7,002
Likes: 2,679
Problem with the power steering system is unless you know the actual fault codes (DTCs) you really can't diagnose the problem.
Instructor
Joined: Apr 2008
Posts: 196
Likes: 32
My steering is always in track mode. Suspension is usually touring.
Had 2 drives with no issues recently. was hot and humid both days.
I tried pushing on the wiring connections that go to the EPS motor, but could not get anything to happen. Was wondering if it may have been a fault in the wiring.
Last edited by NYVette2112; Jul 21, 2017 at 10:22 AM.
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
Failure happened to me in Tour Mode
My steering is always in track mode. Suspension is usually touring.
Had 2 drives with now issues recently. was hot and humid both days.
I tried pushing on the wiring connections that go to the EPS motor, but could not get anything to happen. Was wondering if it may have been a fault in the wiring.
Had 2 drives with now issues recently. was hot and humid both days.
I tried pushing on the wiring connections that go to the EPS motor, but could not get anything to happen. Was wondering if it may have been a fault in the wiring.
Instructor
Joined: Apr 2008
Posts: 196
Likes: 32
Russia is probably hacking our cars
Funny I just received my On-Star monthly report.
They are ok with telling me how much air is in my tires, but not if faults were detected with my steering. (if a fault was detected)
Melting Slicks
Joined: Nov 2013
Posts: 2,705
Likes: 986
From: Annandale VA
Power Steering has been reliable for over 60 years
GM quality control is seriously failing.
Team Owner
Joined: Aug 1999
Posts: 20,318
Likes: 1,905
From: Huntingdon Valley Pa/ Town of Webb NY
Yep happened to me, my 26 miles 4 hour old 2017 Z06/Z07 lost all power steering, as the message was being displayed on my dash, TG no one was coming the other way. Turns out mine seemed to be a connector that was bad