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Discussion Starter #1
Hey Everyone,

My power steering has recently started giving some strange issue. Basically if i turn left or right at a T junction, as i straighten up the steering wheel kind of fights back. It not hugely noticeable, no noise or anything, its just not smooth like it used to be. I put the car up on jack stands and turned it on. move the steering full lock bothways and the steering is fine, no kick back. Also at speed its not really noticeable either. No warning lights or codes either.

Wondering if its potentially failing, early signs...

Any ideas?
 

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Apparently you haven't completed your profile, so we don't know anything about your vehicle possibly apart from you having posted in the 4.3 section. It would help if we knew more including such items as your vehicle's year, mileage, model, engine, 2 wheel or all wheel drive, etc.
 

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How new is the battery? A marginal one can cause all sorts of odd issues.
 

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Discussion Starter #5
Battery I replaced 3 years ago. I checked it recently, it is ome if those maintenance free ones with the little round window. If it shows green its good, which it does. I will put a multimeter on and see what the battery voltage is as well as when its running the engine. It has no issues starting. Where I live it is down to 2 or 3 deg C at night, which can prematurely kill a battery quicker than usual. Will check the above today. Thank you for the suggestion.
 

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I think if your battery or alternator was not supplying enough power to operate the electric motor, your chief symptom would be a lack of power assist when turning the wheel.

Your description of the problem sounds like the power assist continues pushing the wheels into a turn after you release the pressure on the steering wheel. The wheels, when aligned properly, want to return to a straight ahead position all by themselves. It seems that your EPS continues to apply enough steering force to counter-act that natural tendency.

So, my guess would be that your steering is not aligned properly, or the sensor that detects your hand pressure on the steering wheel is not working properly.

Since you said the problem does not occur at highway speeds (i.e. very little steering movement) I believe you may have a bearing on the MacPherson strut which is not moving freely. Once the wheels are turned, the bad bearing prevents them from returning to straight ahead easily. This problem is usually intermittent in the beginning and may only occur when the bearings are moved past a certain point (i.e. only on sharper turns). Another symptom of this problem is when the wheels are being held in a turned position , the sticky bearing will release suddenly and as a result the wheels will straighten suddenly as well. You may also hear a "twang" sound as the coil spring releases it's tension.
 

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From what I've read, the EPS is not active at highway speeds.
 

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Discussion Starter #8
Battery test:
12.6v when engine off. 14.16v when engine running, but after about 5 minutes this has dropped to 13.98v. This is with no accessories on. I turned lights on, higb beam and fan full blast. It drops a but more to 13.96v

I thought it should be about 14.2 to 14.7 under alternator charge, and of couse drop when accessories are running.

I am not sure if this is a failing battery and or alternator/regulator... Battery does seem right at 12.6v with engine off. In fact this is the reading after the car has stood for 2 days without running, and out in the open.
 

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In the winter 14.2 to 14.7 is fine but in the summer it is better to keep the voltage below 14.0 and a good regulator or ECM will do that.

Frank 2015 XLE AWD with 20K+ miles
 

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Your voltage readings seem perfectly normal, and as I said before, the failure of the wheels to return to straight ahead is not a symptom of a lack of power assist.

If you still think the battery and/or alternator is at fault, then test them under the conditions that you experience the problem. Measure the voltage when the wheels are being turned.

If the problem is intermittent, then get a voltmeter that plugs into the cigarette lighter and look at the readings when the problem is occurring.

Edit: pull the fuse to disable EPS and see what happens. NOTE: it will be difficult to turn the wheels without power assist, but they will straighten by themselves.
 

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Battery voltage is normal, both after having sat unused for several days and also with the engine running. When the alternator is charging the battery after the vehicle has sat unused and after starting, the regulator increases the voltage until the battery is fully charged and then decreases it. If concerned about the battery it would be worthwhile to have it load tested, and many auto parts stores will do that at no cost.


Also the EPS increases the load upon the electrical system by quite a lot while it is active and that will momentarily decrease battery voltage until the charging system (alternator and regulator) can generate enough power to recharge it, and that ability increases with increased engine RPM and decreases with decreasing RPM.
 

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Discussion Starter #12
I will try pull the EPS fuse and see if there is any mechanical resistance in returning the wheel to a strait line. That should eliminate any electrical issues. Thanks for that Ricki.
 

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I think the EPS fuse one of those large 60A fuses that are bolted on from underneath. Not easy to remove.
 

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The service manual lists the following possible causes for your symptoms of "failure of the wheels to return properly".



 

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Discussion Starter #16
Hey Guys,


After many hours of trying to figure out what the issue was, it all came to light recently. The problem became worse all of a sudden. At the same time I could hear a rumbling noise from my right front tire, to the point where I pulled over to see if I had a flat. It was not. I drove a further 45km and pulled into a tyre shop to get them to check. The tyres are cooper cs3's. They have been on for ~60k km and still have plenty tread left. However, the guy at the tyre shop immediately spotted the issue and said, your tyre has delaminated...
He also said, don't drive like that for very far, once they start doing that, they blow out. Put the spare on to drive back home and all of a sudden the power steering was 100%, smooth as silk.


I had never though to check the tyres, well, not from a defect perspective. I check pressure and tread depth and rotate front to back every 10k. In fact the power steering problem started shortly after I had rotated last, and got progressively worse, then severe.


I have attached some photos for others that may come across this. The delamination has happened mid tread, and as a result the tread no longer runs in a straight line, it kind of goes left then right then straight, also a bulge can be seen. Some delamination can be seen on the tyre wall.


Hope this helps someone else. I am just happy its not mechanical/electrical and a new set of tyres (not coopers this time) will be had.


Cheers!
 

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Good that you've discovered that the problem apparently is because of tires, and not because of a defect in the power steering. I've never had that tire problem happen in more than 50 years of driving. If it did take place I would get another brand of tires, as you are doing.
 

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The first and last picture you can tell there is a defect for sure. The tire defect is not obvious at a glance but I have seen a friends car that had a more obvious bulge on the sidewall. Just over a month ago I was driving next to a car on the highway and I see smoke from the front tire. The driver was trying to control the vehicle as debris was flying every where. As I passed the car I can see that the entire tire and wheel cover had disintegrated down to the wheel. Luckily the driver made it safely to the shoulder without incident. You were lucky this was not the scenario for you.
 

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I've seen this type of tire failure on my trailer tires and and old truck tire or two but wouldn't expect it on a good brand like Cooper. I've got Cooper SRXs on the RAV4 and CS5s on the Odyssey.

When it happens some internal cording fails causing a bulge in the tread so the tire becomes mildly egg shaped. But at least it gives some warning that something's not right before failing.

That wasn't the case when I had a sidewall bulge that I didn't notice develop on the inside sidewall of the rear tire on my F-250. Apparently it kept getting bigger until it hit the leaf spring and instantly blew out at 70 mph while I was towing my trailer. I got it stopped safely but there wasn't enough left of the tire to tell for sure how it happened. The truck has only had Goodyear or Michelins since.
 
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