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Discussion Starter · #1 ·
Returning from a camping trip in Zion National Park, my van popped up "Power Steering Malfunction. See Owners Manual" on display between the Odo and Tach. It's a bear to drive without any power assist.

Ironically, almost exactly a year ago, as I was returning from a camping trip in Zion, within 50 miles of today's issue, I had the same thing happen. This was on highway US95 in Nevada northbound between Tonopah and Hawthorne. Out in the middle of nowhere. I had no real options but continue. Last year, I stopped at rest stop, and when I restarted the van, the power steering had returned. 10 minutes later, same thing. I stopped in Hawthorne for gas, and again, when the van was restarted, the power steering was back and continued doing is job for the 200 miles left to home.

I took the van into the dealer, and they replaced the entire steering rack assembly - the rack, the electric motor, and the control electronics.

Today, in the same stretch of US95, about 30 miles south of Hawthorne, same thing! I stopped at the exact same gas station in Hawthorne, and when I restarted, the power steering was back, and remained functional for the rest of the drive home.

With that long introduction, I have a suspicion/theory/guess as to a contributing factor. This stretch of road has grooves (rumble strips) cut into it along the center line, just as many roads do on their outer edge, to warn drivers that they are out of their lane. The grooves on this stretch are very aggressive. The speed limit is 75. It's two lanes, pretty straight, with a decent number of trucks and campers/RVs doing less than the speed limit. The grooves are so aggressive, that passing on that section definitely requires two hands on the wheel as the van's tires cross. The steering components take a beating as one front tire and then the other cross over a few seconds of very rough road at 60 to 80 miles per hour.

I'm wondering/guessing/theorizing/pulling things out of dark orifices that the pretty violent rapid "chatter" of one or the other of the front tires crossing over these things is causing the power steering controller to be confused into thinking there is some sort of failure in the power steering unit. Last year, I'm pretty sure the 'malfunction' message appeared while I was cruising along in my lane, but today, the message occurred as the left tire hit the rumble strip when I was pulling left to pass a semi.

It seems like too much of a coincidence to have this same reported malfunction a year apart, 15k miles later, on two different steering racks, on the same section of road under similar conditions.

I don't think I'm going to take it into the dealer this time. Last time, the replacement was $4100 list price. I'm not sure anything's actually broken other than confused firmware in the power steering controller and/or stability control and/or lane assist and/or all of the other computers monitoring the van's dynamics. I think some module is observing readings it wasn't programmed for and is shutting down the power steering with a false alarm fault.

Or, am I just kidding myself.
 

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I think this has been reported by others where going over very rough road or vibration causing roadway patterns causes the steering system to shut down. It most likely is the computer thinking there's a problem from the rapid small movements continuously as its sensor system is extremely precise/sensitive.
 

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It happened to us almost 2 years (January. 2018). We went over an expansion joint on a curving on ramp. That message popped up and the power assist shut off. We drove for another hour or so on the freeway, then stopped for gas, and everything cleared up. It has never returned. We took it to the dealer a couple days after it happened. They were unable to find anything either They did mention another customer who had the same problem after crossing a cattle grate. Sounds like the comment above is correct.
 

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Returning from a camping trip in Zion National Park, my van popped up "Power Steering Malfunction. See Owners Manual" on display between the Odo and Tach. It's a bear to drive without any power assist.

Ironically, almost exactly a year ago, as I was returning from a camping trip in Zion, within 50 miles of today's issue, I had the same thing happen. This was on highway US95 in Nevada northbound between Tonopah and Hawthorne. Out in the middle of nowhere. I had no real options but continue. Last year, I stopped at rest stop, and when I restarted the van, the power steering had returned. 10 minutes later, same thing. I stopped in Hawthorne for gas, and again, when the van was restarted, the power steering was back and continued doing is job for the 200 miles left to home.

I took the van into the dealer, and they replaced the entire steering rack assembly - the rack, the electric motor, and the control electronics.

Today, in the same stretch of US95, about 30 miles south of Hawthorne, same thing! I stopped at the exact same gas station in Hawthorne, and when I restarted, the power steering was back, and remained functional for the rest of the drive home.

With that long introduction, I have a suspicion/theory/guess as to a contributing factor. This stretch of road has grooves (rumble strips) cut into it along the center line, just as many roads do on their outer edge, to warn drivers that they are out of their lane. The grooves on this stretch are very aggressive. The speed limit is 75. It's two lanes, pretty straight, with a decent number of trucks and campers/RVs doing less than the speed limit. The grooves are so aggressive, that passing on that section definitely requires two hands on the wheel as the van's tires cross. The steering components take a beating as one front tire and then the other cross over a few seconds of very rough road at 60 to 80 miles per hour.

I'm wondering/guessing/theorizing/pulling things out of dark orifices that the pretty violent rapid "chatter" of one or the other of the front tires crossing over these things is causing the power steering controller to be confused into thinking there is some sort of failure in the power steering unit. Last year, I'm pretty sure the 'malfunction' message appeared while I was cruising along in my lane, but today, the message occurred as the left tire hit the rumble strip when I was pulling left to pass a semi.

It seems like too much of a coincidence to have this same reported malfunction a year apart, 15k miles later, on two different steering racks, on the same section of road under similar conditions.

I don't think I'm going to take it into the dealer this time. Last time, the replacement was $4100 list price. I'm not sure anything's actually broken other than confused firmware in the power steering controller and/or stability control and/or lane assist and/or all of the other computers monitoring the van's dynamics. I think some module is observing readings it wasn't programmed for and is shutting down the power steering with a false alarm fault.

Or, am I just kidding myself.
I just ran on rumble strip along highway maybe 200 ft— steering malfunction happened— was in middle of nowhere Arkansas — pulled over, found your post— so, I shut off engine waited for dash message to go off—started van and steering was back!!!!! THAMKS SO MUCH for posting this ! Sure would like to know why it does this!!
 

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Discussion Starter · #6 ·
Two weeks ago in a construction zone on I80 outside of salt lake city, there was a lane shift across uneven concrete, and the steering failed. That was a bit scary
 

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It does it because the sensors that monitors the electric power steering movements are extremely precise, along with extremely precise software tolerances. The vibration causes repeated fast small movements of the steering over a continuous period of time which is triggering a fail safe in the software so it shuts down the motor assist. It probably thinks something is malfunctioning and the driver is fighting it (small constant back and forth movements) so it disables the motor. Makes sense, but obviously such a sensitive system will not be fool proof in the right conditions.
 

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Designed by the folks who brought you the 737 MAX? I mean, it seems like very, very poor systems design to misinterpret routine road conditions as a failed component, and even worse to design the system to shut down a critical component regardless of occupant safety. What the heck do these beasts do on cobblestones? "Precision" is no excuse for poor design. I haven't experienced this "feature" myself, so I appreciate the forewarning.

"DOS ain't done 'til Lotus won't run."
 
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The Metris steering system is “intelligent” (quotes are important) in that it automatically corrects your steering to maintain a straight line, particularly with regard to road crown; under some circumstances you can actually observe the van steer itself along certain types of gentle curves on deeply crowned roads. It is not an autonomous driving system; it’s an anti-fatigue system that works incredibly well in that function.

However, the system IS capable, under certain malfunction conditions, of attempting to steer in a direction the driver does not intend to go; it has to do with lane keeping assist, a feature the rack can accommodate but the hardware for it is not otherwise installed in the Metris. It is designed to shut down the system entirely (pawo is correct) in a fail safest manner when it is detecting what appears to be a fight between the driver and the self-correction system, without a clear reason why.

Power steering failing entirely is a superior safety condition verses the system attempting to steer heavily in a direction the driver does not want to go (which could cause the van to veer sharply off the road or even blow apart the front suspension given the 50ish degree cut angle this rack is capable of). It is obviously a poor design choice; the system should simply can the self correction system and operate manually until restart. I am not so familiar with the technical working of the rack; it is possible that simply hard shutting off The correction system is not technically possible.
 

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I wonder if it also has to do with the firm suspension on these vans vs sedans. My GLK has a very similar (if not the same) electric steering system with assist functions and it has never had any errors. Though my van has not either so far. Perhaps these rumble strips and cattle grates people keep mentioning are just above and beyond rough road/vibration levels than were designed into the tolerances of the system. I've gone over some plenty rough roads in both of my vehicles and zero problems so far, including normal rumble strips. Almost 40,000 miles worth between the two vehicles.
 

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The sterness of the suspension may have something to do with it. It might be the condition of the cattle grates or the specific rumble strip might simply confuse the system to the point of convincing itself that a potential failure of the correction system may have occurred. User error is also a possibility- perhaps I should say user contribution- in either spending too long on a rumble strip or the way they react to it. It is also possible that these specific vans have some minorly defective component or sensor. It is most likely a combination of several of these frankly- or all four.

I’ve put 123k miles on mine and so far it hasn’t happened, and god willing it won’t. It is important to understand that the system of fail “safe” would be weighted to responding to any hint of the system going haywire; the potential danger of it it failing and NOT shutting off the system is massive.

If I was to take a guess, these specific rumble strips and cattle grates are very very North America specific, rare even here, and therefore not something whose dynamic with the steering system was programmed for or thought of.
 

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Discussion Starter · #12 ·
Earlier this month, while driving I80 west of Salt Lake City, traffic lanes were diverted left in a construction zone. While crossing uneven concrete pavement, I heard the warning beep, saw the "Power Steering Malfunction" message, and lost power assist. That was scary as the lanes diverted right again quickly, and I was struggling to steer the van.

I filled out a complaint at the National Highway Traffic Safety Administration website today detailing the four failures on two different steering racks. I also included links to this thread and a similar one started by @Vanz Power Steering Malfunction

Maybe something will come of it. Maybe not.
 
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